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1
To, Chun-hung. "Stochastic model of daily rainfall." Click to view the E-thesis via HKUTO, 1989. http://sunzi.lib.hku.hk/hkuto/record/B31976098.
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Nie, Congling. "Wind/Rain Backscatter Modeling and Wind/Rain Retrieval for Scatterometer and Synthetic Aperture Radar." BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1632.
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Using co-located space-borne satellite (TRMM PR, ESCAT on ERS 1/2) measurements, and numerical predicted wind fields (ECMWF), the sensitivity of C-band backscatter measurement to rain is evaluated. It is demonstrated that C-band radar backscatter can be significantly altered by rain surface perturbation, an effect that has been previously neglected. A low-order wind/rain backscatter model is developed that has inputs of surface rain rate, incidence angle, wind speed, wind direction, and azimuth angle. The wind/rain backscatter model is accurate enough for describing the total backscatter in raining areas with relatively low variance. Rain has a more significant impact on measurements at high incidence angles than at low incidence angles. Using three distinct regimes, the conditions for which wind, rain, and both wind and rain can be retrieved from scatterometer backscatter measurements are determined. The effects of rain on ESCAT wind-only retrieval are evaluated. The additional scattering from rain causes estimated wind speeds to be biased high and estimated wind directions to be biased toward the along-track direction in heavy rains. To compensate for rain-induced backscatter, we develop a simultaneous wind/rain retrieval method (SWRR), which simultaneously estimates wind and rain from ESCAT backscatter measurements with an incidence angle of over 40 degrees. The performance of SWRR under typical wind/rain conditions is evaluated through simulation and validation with collocated TRMM PR and ECMWF data sets. SWRR is shown to significantly improve wind velocity estimates and the SWRR-estimated rain rate has relatively high accuracy in moderate to heavy rain cases. RADARSAT-1 ScanSAR SWA images of Hurricane Katrina are used to retrieve surface wind vectors over the ocean. Collocated H*wind wind directions are used as the wind direction estimate and the wind speed is derived from SAR backscatter measurements by inversion of a C-band HH-polarization Geophysical Model Function (GMF) that is derived from the VV-polarization GMF, CMOD5, using a polarization ratio model. Because existing polarization models do not fit the ScanSAR SWA data well, a recalibration model is proposed to recalibrate the ScanSAR SWA images. Validated with collocated H*wind wind speed estimates, the mean difference between SAR-retrieved and H*wind speed is small and the root mean square (RMS) error is below 4 m/s. Rain effects on the ScanSAR measurements are analyzed for three different incidence angle ranges using collocated ground-based Doppler weather radar (NEXRAD) rain measurements. Compared with the scatterometer-derived model, the rain-induced backscatter observed by the ScanSAR at incidence angles 44 to 45.7 degrees is consistent with the scatterometer-derived model when the polarization difference between HH and VV polarizations is considered.
3
To, Chun-hung, and 杜振雄. "Stochastic model of daily rainfall." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31976098.
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Faridhosseini, Alireza. "Evaluation of Summer Rainfall Estimation by Satellite Data using the ANN Model for the GCM Subgrid Distribution." Thesis, The University of Arizona, 1998. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0021_m_sip1_w.pdf&type=application/pdf.
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Ramdass, Indarjit. "Modelling forest dynamics and management of natural tropical rain forests." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/11890.
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Cardoso, Tamre Porter. "A hierarchical Bayes model for combining precipitation measurements from different sources /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/6372.
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SOUZA, RODOLFO SABOIA LIMA DE. "A RAIN INDUCED ATTENUATION PREDICTION MODEL IN TROPICAL AND EQUATORIAL REGIONS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1992. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9513@1.
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A propagação das ondas eletromagnéticas em freqüências
superiores a 10 GHz sofre uma degradação causada pela
chuva. O efeito da precipitação é particularmente
importante em regiões de clima tropical e equatorial
onde
se observam as mais elevadas taxas de precipitação. Este
trabalho apresenta resultados de um programa de medidas
de
propagação realizado no Brasil, desde 1987, utilizando
radiômetros operando na faixa de 12 GHz e pluviômetros.
A partir dos dados de atenuação e taxa de precipitação
medidos simultaneamente em 6 locais em diferentes
regiões
do Brasil, durante pelo menos 1 ano, que forneceram
distribuições estatísticas de 10 anos em 6 estações, foi
desenvolvido um modelo de previsão da atenuação causada
pela chuva em enlaces satélite.
Apresenta-se ainda resultados do estudo do comportamento
dinâmico da atenuação por chuvas.The rain attenuation is a major impairment on the radio wave propagation at frequencies above 10 GHz. The rain effect is particularly important in tropical and equatorial regions which experience the most severe rain rates. This work presents results of the propagation measurement campaign conducted in Brazil since 1987, using radiometers, operating at the frequency of 12 GHz, and raingauges. A rain induced attenuation prediction model for satellite- Earth links was developed from the data of 10 year- stations measured in Brazil. The results of the dynamic behaviour of rain attenuation are also presented.
8
DeSordi, Steven Paul. "Utah local area model sensitivity to boundary conditions for summer rain simulations." Wright-Patterson AFB, Ohio : Dept. of the Air Force, 1996. http://stinet.dtic.mil/cgi-bin/fulcrum%5Fmain.pl?database=ft%5Fu2&searchid=0&keyfieldvalue=ADA319136&filename=%2Ffulcrum%2Fdata%2FTR%5Ffulltext%2Fdoc%2FADA319136.pdf.
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Thesis (M.S.)--University of Utah, 1996. Thesis from the University of Utah's Department of Meteorology explores the sensitivity of the pecipitation-predicting model known as the Utah Limited Area Model (LAM) to the way that the lateral and upper boundary conditions are applied. The approach is different from most past studies of LAM boundary specification because it is founded upon a medium-range simulation using real data. Many other studies of boundary conditions have used idealized cases or short-term (a few days or less) predictions.Title from web page (viewed Oct. 30, 2003). "96-084." "August 1996." Includes bibliographical references p. [110]-112. Also available in print version.
9
Nielsen, Seth N. "A wind and rain backscatter model derived from AMSR and SeaWinds data /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1979.pdf.
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Nielsen, Seth Niels. "A Wind and Rain Backscatter Model Derived from AMSR and SeaWinds Data." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1410.
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The SeaWinds scatterometers aboard the QuikSCAT and ADEOS II satellites were originally designed to measure wind vectors over the ocean by exploiting the relationship between wind-induced surface roughening and the normalized radar backscatter cross-section. Recently, an algorithm for simultaneously retrieving wind and rain (SWR) from scatterometer measurements was developed that enables SeaWinds to correct rain-corrupted wind measurements and retrieve rain rate data. This algorithm is based on co-locating Tropical Rainfall Measuring Mission Precipitation Radar (TRMM PR) and SeaWinds on QuikSCAT data. In this thesis, a new wind and rain radar backscatter model is developed for the SWR algorithm using a global co-located data set with rain data from the Advanced Microwave Scanning Radiometer (AMSR) and backscatter data from the SeaWinds scatterometer aboard the Advanced Earth Observing Satellite 2 (ADEOS II). The model includes the effects of phenomena such as backscatter due to wind stress, atmospheric rain attenuation, and effective rain backscatter. Rain effect parameters of the model vary with integrated rain rate, which is defined as the product of rain height and rain rate. This study accounts for rain height in the model in order to calculate surface rain rate from the integrated rain rate. A simple model for the mean rain height versus latitude and longitude is proposed based on AMSR data and methods of incorporating this model into the SWR retrieval process are developed. The performance of the new SWR algorithm is measured by comparison of wind vectors and rain rates to the previous SWR algorithm, AMSR rain rates, and NCEP numerical weather prediction winds. The new SWR algorithm produces accurate rain estimates and detects rain with a low false alarm rate. The wind correction capabilities of the SWR algorithm are effective at correcting rain-induced inaccuracies. A qualitative comparison of the wind and rain retrieval for Hurricane Isabel demonstrates these capabilities.
11
Perales, Javier, Gianpierre Zapata, and Carlos Raymundo. "Energy model based on fluvial rainfall for the rural population with torrential rain." Springer Science and Business Media Deutschland GmbH, 2019. http://hdl.handle.net/10757/656264.
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El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.In Latin America, the lack of electricity has been a serious problem for over several years. To overcome this lack of supply in electricity supply, hydraulic energy is now being used in a greater proportion to fulfill the electricity needs in the rural areas. Investigations have been conducted to assess the environmental conditions of these rural areas to optimize the functionality of turbines used for hydraulic energy generation. However, there are very few focused on turbines of less than 0.5 kW generation. The proposed study aims to analyze the positioning of the blades of the cross-flow turbines and designing an electric generation system for rural dwellings. A simulation of each evaluated design was performed, and the power generated from these turbines was calculated. The results show that the power outputs initially were high and stabilized at a value of approximately 180 W, hence satisfying the minimum demands of a rural house.
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Goodrich, David Charles. "Basin Scale and Runoff Model Complexity." Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/614028.
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Distributed Rainfall-Runoff models are gaining widespread acceptance; yet, a
fundamental issue that must be addressed by all users of these models is definition
of an acceptable level of watershed discretization (geometric model complexity). The
level of geometric model complexity is a function of basin and climatic scales as well
as the availability of input and verification data. Equilibrium discharge storage is
employed to develop a quantitative methodology to define a level of geometric model
complexity commensurate with a specified level of model performance. Equilibrium
storage ratios are used to define the transition from overland to channel -dominated
flow response. The methodology is tested on four subcatchments in the USDA -ARS
Walnut Gulch Experimental Watershed in Southeastern Arizona. The catchments
cover a range of basins scales of over three orders of magnitude. This enabled a
unique assessment of watershed response behavior as a function of basin scale.
High quality, distributed, rainfall -runoff data was used to verify the model (KINEROSR). Excellent calibration and verification results provided confidence in
subsequent model interpretations regarding watershed response behavior. An
average elementary channel support area of roughly 15% of the total basin area is
shown to provide a watershed discretization level that maintains model performance
for basins ranging in size from 1.5 to 631 hectares. Detailed examination of
infiltration, including the role and impacts of incorporating small scale infiltration
variability in a distribution sense, into KINEROSR, over a range of soils and
climatic scales was also addressed. The impacts of infiltration and channel losses
on runoff response increase with increasing watershed scale as the relative influence
of storms is diminished in a semiarid environment such as Walnut Gulch. In this
semiarid environment, characterized by ephemeral streams, watershed runoff
response does not become more linear with increasing watershed scale but appears
to become more nonlinear.
13
Henkel, Arthur Frederick. "Regionalization of southeast Arizona precipitation distributions in a daily event-based watershed hydrologic model." Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_26_sip1_w.pdf&type=application/pdf.
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Sulistiyono, Heri. "Rainfall-runoff model calibration using experimental designs and response surface methodology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ42452.pdf.
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Matzoros, Athanasios. "A junction based model of air pollution from urban road networks." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291748.
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Ma, Bin-Bing. "Passive acoustic detection and measurement of rainfall at sea and an empirical ocean ambient sound model /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/11045.
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Driejana, Ir. "Wet and dry deposition in the Derbyshire Peak District, Northern England." Thesis, Manchester Metropolitan University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390785.
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Reed, Seann Mischa. "Use of digital soil maps in a rainfall-runoff model /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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SOUZA, RODRIGO MARTINS DE. "A SEMI-EMPIRIC CONSISTENT MODEL FOR RAIN ATTENUATION PREDICTION IN TERRESTRIAL AND SATELLITE RADIO LINKS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9528@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCom a crescente utilização de sistemas de acesso sem fio ponto-multiponto em banda larga, operando em freqüências cada vez mais elevadas, cresce também a necessidade do desenvolvimento de novos modelos, mais precisos e consistentes, para a previsão da atenuação por chuvas, principal efeito da propagação em freqüências superiores a 10 GHz. Este trabalho apresenta uma modelagem semi-empírica para a previsão do comportamento estatístico da atenuação por chuvas em enlaces rádio terrestres ponto-a- ponto e via satélite. Os modelos foram desenvolvidos com base em resultados de medições conjuntas de taxa de precipitação e atenuação por chuvas em diversas regiões do Brasil, realizadas no período de desenvolvimento deste trabalho, além de medidas de várias partes do mundo, disponíveis no banco de dados de propagação da União Internacional de Telecomunicações (UIT-R). Os modelos desenvolvidos permitem obter a distribuição cumulativa de probabilidades da atenuação por chuvas a partir da distribuição da taxa de precipitação medida ou estimada na região do enlace. Embora existam diversos modelos propostos na literatura para previsão da atenuação em enlaces terrestres ou em enlaces via satélite, duas características importantes não são encontradas, conjuntamente, na maioria deles: utilizar, como base para a previsão, a distribuição da taxa de precipitação em toda a faixa de percentagens de tempo de interesse, e não apenas em um ou dois pontos; e manter consistência entre os modelos para os casos terrestre e via satélite. Além não de atender a estes requisitos, os modelos propostos apresentam erros de previsão menores ou equivalentes aos dos principais modelos da literatura, quando testados contra os resultados disponíveis de medidas em enlaces reais.
The development of new technologies for broadband wireless access, using increasingly higher frequencies, points to the necessity of more accurate methods for rain attenuation, that represents the most serious impairment for radio systems operating in frequencies above 10 GHz. This work presents semi-empirical models for the prediction of rain attenuation in terrestrial and satellite links. The models were developed using data obtained in concurrent measurements of rain attenuation and point rainfall rate in different regions of Brazil. Some of these measurements were performed as part of this work and some were already available from previous measurements campaigns. Data available in the UIT-R data banks of propagation measurements were also used, in order to develop global methods. The models that have been developed allow the prediction of the cumulative probability distribution of rain attenuation from the cumulative distribution of point rainfall rate in the region of the link. Although several methods with these purpose can be found in the technical literature, the ones developed in this work present some important features that are not found, as a whole, in any of those models: they use the full rainfall rate distribution over the entire range of time percentages of interest; the terrestrial and satellite models are consistent, that is, the elements used in the terrestrial prediction model are kept in the satellite prediction model that involves a mor complex geometry. Besides that, the models proposed show an excelent performance in terms of prediction error, when compared with measured data.
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Hajjam, Sohrab. "Real-time flood forecasting model intercomparison and parameter updating rain gauge and weather radar data." Thesis, University of Salford, 1997. http://usir.salford.ac.uk/43019/.
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This thesis describes the development of real-time flood forecasting models at selected catchments in the three countries, using rain gauge and radar derived rainfall estimates and time-series analysis. An extended inter-comparison of real-time flood forecasting models has been carried out and an attempt has been made to rank the flood forecasting models. It was found that an increase in model complexity does not necessarily lead to an increase in forecast accuracy. An extensive analysis of group calibrated transfer function (TF) models on the basis of antecedent conditions of the catchment and storm characteristics has revealed that the use of group model resulted in a significant improvement in the quality of the forecast. A simple model to calculate the average pulse response has also been developed. The development of a hybrid genetic algorithm (HGA), applied to a physically realisable transfer function model is described. The techniques of interview selection and fitness scaling as well as random bit mutation and multiple crossover have been included, and both binary and real number encoding technique have been assessed. The HGA has been successfully applied for the identification and simulation of the dynamic TF model. Four software packages have been developed and extensive development and testing has proved the viability of the approach. Extensive research has been conducted to find the most important adjustment factor of the dynamic TF model. The impact of volume, shape and time adjustment factors on forecast quality has been evaluated. It has been concluded that the volume adjustment factor is the most important factor of the three. Furthermore, several attempts have been made to relate the adjustment factors to different elements. The interaction of adjustment factors has also been investigated. An autoregressive model has been used to develop a new updating technique for the dynamic TF model by the updating of the B parameters through the prediction of future volume adjustment factors over the forecast lead-time. An autoregressive error prediction model has also been combined with a static TF model. Testing has shown that the performance of both new TF models is superior to conventional procedures.
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Wallinder, Sol. "Skyfall över Västerås : en konsekvensstudie." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-255823.
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Skyfall kan leda till stora konsekvenser för samhället, framförallt i en stad då den urbana miljön är känslig för extrema händelser. Västerås stad har tidigare drabbats av skyfall där följderna har varit kostsamma. Den senaste forskningen pekar på att intensiva regnhändelser kommer bli allt mer vanligt förekommande, därför är det intressant att undersöka vilka konsekvenser dessa regn kan leda till. En analys har gjorts med utgångspunkt från SMHI:s lågpunktskartering över Västerås. Utifrån denna kartering undersöktes vilka förorenade områden, bostadsområden, exploateringsområden, infrastruktur, vårdcentraler, skolor, nätstationer och prioriterade pumpar som ligger i lågpunktsområden. Denna jämförelse har gjorts i ArcGIS. Där konstaterades att många viktiga objekt ligger i låga områden och då riskerar att översvämmas. Det gäller främst sjukhusområdet, mindre bostadsområden, cykel-underfarter och nätstationer. Resultaten från jämförelsen med lågpunktskarteringen låg därefter som grund för val av vidare studie där en fördjupad konsekvensstudie har gjorts över sjukhusområdet då detta är en samhällsviktig funktion som tidigare har översvämmats vid skyfall. En hydraulisk modell har byggts upp i programmet MIKE 21 Flow Model där ett regn med återkomsttiden 100 år har simulerats och dess konsekvenser över sjukhusets avrinningsområde har undersökts. Simuleringen visar att stora ytor vid främst sjukhusområdet och i bostadsområden med tät bebyggelse översvämmas. Stora vattendjup ansamlas bland annat vid sjukhusets akutingång och längs E 18 vid Korsängsmotet och Folkparksmotet. Känslighetsanalyser har även utförts i MIKE 21 Flow Model för att undersöka bland annat hur olika stora regn påverkar resultaten samt hur känslig resultaten är för val av Mannings tal (M). Resultaten visar att intensivare regn medför framförallt en större översvämmad yta och att ett konstant värde på M = 40 hade varit en rimlig förenkling för detta område. En kontroll har utförts där skyfallet som föll över Västerås 8 juli 2012 har simulerats i MIKE 21 Flow Model. Resultaten från de hydrauliska simuleringarna har även jämförts med SMHI:s lågpunktskartering där det konstaterades att många lågpunkter inte översvämmas, men samtidigt att flera områden som inte är lågpunktsområden översvämmas vid simulerade skyfall.Heavy rainfall can lead to large consequences for society, especially in a city since the urban environment is sensitive to extreme events. Västerås has earlier suffered heavy rains and according to the latest research, more intense future rainfall is to be expected. It’s therefore interesting to examine the possible implications of these rains. SMHI has produced a map of low areas in the city of Västerås. Based on this mapping, this study evaluated the occurrence of contaminated areas, residential areas, development areas, infrastructure, health centers, schools, power stations and prioritized pumps in low areas. This comparison has been made in ArcGIS. It could be established that many important objects are located in low areas and therefore have a risk of being flooded by heavy rain showers. This primarily concerns the hospital, smaller residential areas, underpasses and power stations. The results from the comparison with low areas were used as background information when the hospital was chosen for further studies. The hospital is an important public function that has previously been flooded by heavy rain showers. By using the program MIKE 21 Flow Model, a hydraulic model has been set up where a rain with a return period of 100 years has been simulated and its consequences on the catchment area has been explored. The simulation shows that large flooded areas will occur around the hospital and in residential areas. A large water depth is predicted to occur at the hospital's emergency entrance and along E 18 at Korsängsmotet and Folkparksmotet. Sensitivity analyses were also performed in the MIKE 21 Flow Model to investigate how different kinds of rain affect the results, and how sensitive the results are to the choice of Manning's M values. From the results it can be seen that intense rainfall means primarily a greater flooded surface and that a constant value of M = 40 had been a reasonable simplification for the simulated area. A simulation has been performed in MIKE 21 Flow Model with the heavy rain shower that fell over Västerås July 8, 2012. A comparison has also been made between the results from the hydraulic simulations and the mapping of low areas made by SMHI. It was found that many of the lower areas were not flooded, but also that several areas that were not found as low areas were flooded in simulated rainfalls.
22
Karnieli, Arnon 1952. "Storm runoff forecasting model incorporating spatial data." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/191138.
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This study is concerned with design forecasting of storm hydrographs with emphasis on runoff volume and peak discharge. The objective of the study was to develop, calibrate and test a method for forecasting storm runoff from small semi-arid watersheds using an available prediction model. In order to turn the selected prediction model into a forecasting model an objective procedure in terms of an API-type model was developed for evaluating the soil moisture deficit in the upper soil layer at the beginning of each storm. Distinction was made between the physically-based parameters and the other fitting parameters. The rainfall excess calculation was computed by solving the Green and Ampt equation for unsteady rainfall conditions using the physically-based parameters. For the physically-based parameters a geographic information system was developed in order to account for the variability in time and space of the input data and the watershed characteristics and to coregister parameters on a common basis. The fitting parameters were used to calibrate the model on one subwatershed in the Walnut Gulch Experimental Watershed while the physically-based parameters remained constant. Two objective functions were selected for the optimization procedure. These functions expressed the goodness of fit between the calculated hydrograph volume and peak discharge and the observed volume and peak discharge. Linear relationships between the effective matric potential parameter and the two objective functions obtained from the sensitivity analyses made it possible to develop a bilinear interpolation algorithm to minimize, simultaneously, the difference between the calculated and observed volume and peak discharge. The prediction mode of the model was tested both on different storm events on the same subwatershed and on another subwatershed with satisfactory results. In the prediction mode the effective matric potential parameter was allowed to vary from storm to storm, however, in the forecasting mode these values were obtained from the API model. Relatively poor results were obtained in testing the forecasting mode on another subwatershed. These errors were able to be corrected by changing the channel losses fitting parameters.
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Mwelwa, Elenestina Mutekenya. "The application of the monthly time step Pitman rainfall-runoff model to the Kafue River basin of Zambia." Connect to this title online, 2004. http://eprints.ru.ac.za/173/.
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Kruk, N. S., Peter Hoffmann, and Armin Raabe. "Modeling of orographic precipitation events in South America to couple hydrological and atmospheric models; part 1: The simulation of rain with the Mesoscale Model GESIMA." Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-222251.
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Globalmodelle sind aufgrund ihres groben Gitters (60 x 60 km) nur unzureichend in der Lage kleinskalige Prozesse (orographische Niederschlagsverstärkung) in der Atmosphäre aufzulösen. Mit Mesoskalenmodellen z.B. dem GESIMA (5 x 5 km) können deshalb die physikalische Grundlagen der Atmosphäre (Wolken- und Niederschlagsbildung) besser studiert und eine Kopplung mit hydrologischen Abflussmodellen erprobt werden. Zukünftig sieht dieses Projekt genau das vor, wobei der erste Teil, die Arbeit mit dem meteorologische Modell hier vorgestellt werden soll. Starkniederschlagserreignisse sind vielerorts auf der Welt mit charakteristischen Wetterlagen verbunden, die quasi über Tage unverändert ergiebigen Regen produzieren. Initialisiert mit den lokalen Vertikalprofilen aus Radiosondendaten, produzieren das prognostische Mesoskalenmodell GESIMA und das diagnostische Niederschlagsberechungsverfahren (MAXRR) maximale Regenmengen vergleichbarer GrößenordnungGlobal models are insufficient to solve small scale atmospheric processes (e.g. orographic precipitation) due to their gross resolution (60 x 60 km). With mesoscale models e.g. the GESIMA (5 x 5 km), the physical fundamentals of the atmosphere (formation of precipitation and clouds) can better be studied and a coupling with hydrological models be tested through. This project plans exactly, as a first step, the work with the cited meteorological model. Heavy rainfall events are connected with characteristic weather conditions in many places in the world which produce invariably rain quasi over days. Initialized with the local vertical profiles from radiosonde data, the prediction model GESIMA and the diagnostic model MAXRR produced rain quantities of comparable order of magnitude
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Gupta, Sujata. "Carbon dioxide abatement in an empirical model of the Indian economy : an integration of micro and macro analysis." Thesis, London Business School (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309510.
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Elsenbeer, Helmut, Daniel Lorieri, and Mike Bonell. "Mixing model approaches to estimate storm flow sources in an overland flow-dominated tropical rain forest catchment." Universität Potsdam, 1995. http://opus.kobv.de/ubp/volltexte/2008/1694/.
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Previous hydrometric studies demonstrated the prevalence of overland flow as a hydrological pathway in the tropical rain forest catchment of South Creek, northeast Queensland. The purpose of this study was to consider this information in a mixing analysis with the aim of identifying sources of, and of estimating their contribution to, storm flow during two events in February 1993. K and acid-neutralizing capacity (ANC) were used as tracers because they provided the best separation of the potential sources, saturation overland flow, soil water from depths of 0.3, 0.6, and 1.2 m, and hillslope groundwater in a two-dimensional mixing plot. It was necessary to distinguish between saturation overland flow, generated at the soil surface and following unchanneled pathways, and overland flow in incised pathways. This latter type of overland flow was a mixture of saturation overland flow (event water) with high concentrations of K and a low ANC, soil water (preevent water) with low concentrations of K and a low ANC, and groundwater (preevent water) with low concentrations of K and a high ANC. The same sources explained the streamwater chemistry during the two events with strongly differing rainfall and antecedent moisture conditions. The contribution of saturation overland flow dominated the storm flow during the first, high-intensity, 178-mm event, while the contribution of soil water reached 50% during peak flow of the second, low-intensity, 44-mm event 5 days later. This latter result is remarkably similar to soil water contributions to storm flow in mountainous forested catchments of the southeastern United States. In terms of event and preevent water the storm flow hydrograph of the high-intensity event is dominated by event water and that of the low-intensity event by preevent water. This study highlights the problems of applying mixing analyses to overland flow-dominated catchments and soil environments with a poorly developed vertical chemical zonation and emphasizes the need for independent hydrometric information for a complete characterization of watershed hydrology and chemistry.
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Baheru, Thomas. "Development of Test-Based Wind-Driven Rain Intrusion Model for Hurricane-Induced Building Interior and Contents Damage." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1127.
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Major portion of hurricane-induced economic loss originates from damages to building structures. The damages on building structures are typically grouped into three main categories: exterior, interior, and contents damage. Although the latter two types of damages, in most cases, cause more than 50% of the total loss, little has been done to investigate the physical damage process and unveil the interdependence of interior damage parameters. Building interior and contents damages are mainly due to wind-driven rain (WDR) intrusion through building envelope defects, breaches, and other functional openings. The limitation of research works and subsequent knowledge gaps, are in most part due to the complexity of damage phenomena during hurricanes and lack of established measurement methodologies to quantify rainwater intrusion. This dissertation focuses on devising methodologies for large-scale experimental simulation of tropical cyclone WDR and measurements of rainwater intrusion to acquire benchmark test-based data for the development of hurricane-induced building interior and contents damage model. Target WDR parameters derived from tropical cyclone rainfall data were used to simulate the WDR characteristics at the Wall of Wind (WOW) facility. The proposed WDR simulation methodology presents detailed procedures for selection of type and number of nozzles formulated based on tropical cyclone WDR study. The simulated WDR was later used to experimentally investigate the mechanisms of rainwater deposition/intrusion in buildings. Test-based dataset of two rainwater intrusion parameters that quantify the distribution of direct impinging raindrops and surface runoff rainwater over building surface — rain admittance factor (RAF) and surface runoff coefficient (SRC), respectively — were developed using common shapes of low-rise buildings. The dataset was applied to a newly formulated WDR estimation model to predict the volume of rainwater ingress through envelope openings such as wall and roof deck breaches and window sill cracks. The validation of the new model using experimental data indicated reasonable estimation of rainwater ingress through envelope defects and breaches during tropical cyclones. The WDR estimation model and experimental dataset of WDR parameters developed in this dissertation work can be used to enhance the prediction capabilities of existing interior damage models such as the Florida Public Hurricane Loss Model (FPHLM).
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Luckemeier, Richard Ewald 1948. "A rainfall-runoff model for an urban watershed in Tucson, Arizona." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277165.
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The U.S. Geological Survey and the City of Tucson, Arizona, have been collecting rainfall and runoff data on several watersheds in the Tucson area for several years. Among the purposes of this project is to use the data to test rainfall-runoff models in an effort to find one to successfully simulate flood flows in Tucson. One such model, the Distributed Routing Rainfall-Runoff Model (DR3M), was tested using data collected on Rob Wash in Tucson. It was found DR3M performs about as well as it does in other parts of the United States, although it tends to underestimate flood flows for large storms and overestimate flows for smaller storms. Unique features with regard to the hydrology of urban Tucson require special attention when using DR3M; these features are associated with the nature of dry washes and summer rainfall in Tucson. Experience indicates DR3M is not truly a deterministic model.
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Goodrich, David Charles. "Geometric simplification of a distributed rainfall-runoff model over a range of basin scales." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185051.
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Distributed rainfall-runoff models are gaining widespread acceptance; yet, a fundamental issue that must be addressed by all users of these models is definition of an acceptable level of watershed discretization (geometric model complexity). The level of geometric model complexity is a function of basin and climatic scales as well as the availability of input and verification data. Equilibrium discharge storage is employed to develop a quantitative methodology to define a level of geometric model complexity commensurate with a specified level of model performance. Equilibrium storage ratios are used to define the transition from overland to channel-dominated flow response. The methodology is tested on four subcatchments in the USDA-ARS Walnut Gulch Experimental Watershed in southeastern Arizona. The catchments cover a range of basins scales of over three orders of magnitude. This enabled a unique assessment of watershed response behavior as a function of basin scale. High quality, distributed, rainfall-runoff data were used to verify the model (KINEROSR). Excellent calibration and verification results provided confidence in subsequent model interpretations regarding watershed response behavior. An average elementary channel support area of roughly 15% of the total basin area is shown to provide a watershed discretization level that maintains model performance for basins ranging in size from 1.5 to 631 hectares. Detailed examination of infiltration, including the role and impacts of incorporating small-scale infiltration variability in a distribution sense, into KINEROSR, over a range of soils and climatic scales was also addressed. The impacts of infiltration and channel losses on runoff response increase with increasing watershed scale as the relative influence of storms is diminished in a semi-arid environment such as Walnut Gulch. In this semi-arid environment, characterized by ephemeral streams, watershed runoff response does not become more linear with increasing watershed scale but appears to become more nonlinear.
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EL-Nimri, Salem. "AN IMPROVED MICROWAVE RADIATIVE TRANSFER MODEL FOR OCEAN EMISSIVITY AT HURRICANE FORCE SURFACE WIND SPEED." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2523.
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An electromagnetic model for predicting the microwave blackbody emission from the ocean surface under the forcing of strong surface winds in hurricanes is being developed. This ocean emissivity model will be incorporated into a larger radiative transfer model used to infer ocean surface wind speed and rain rate in hurricanes from remotely sensed radiometric brightness temperature. The model development is based on measurements obtained with the Stepped Frequency Microwave Radiometer (SFMR), which routinely flys on the National Oceanic and Atmospheric Administration's hurricane hunter aircraft. This thesis presents the methods used in the wind speed model development and validation results for wind speeds up to 70 m/sec. The ocean emissivity model relates changes in measured C-band radiometric brightness temperatures to physical changes in the ocean surface. These surface modifications are the result of the drag of surface winds that roughen the sea surface, produce waves, and create white caps and foam from the breaking waves. SFMR brightness temperature measurements from hurricane flights and independent measurements of surface wind speed are used to define empirical relationships between microwave brightness temperature and surface wind speed. The wind speed model employs statistical regression techniques to develop a physics-based ocean emissivity model dependent on geophysical parameters, such as wind speed and sea surface temperature, and observational parameters, such as electromagnetic frequency, electromagnetic polarization, and incidence angle.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
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Kruk, N. S., Peter Hoffmann, and Armin Raabe. "Modeling of orographic precipitation events in South America to couple hydrological and atmospheric models; part 1: The simulation of rain with the Mesoscale Model GESIMA." Wissenschaftliche Mitteilungen des Leipziger Instituts für Meteorologie ; 37 = Meteorologische Arbeiten aus Leipzig … und Jahresbericht … des Instituts für Meteorologie der Universität Leipzig ; 11 (2006), S. 137-148, 2006. https://ul.qucosa.de/id/qucosa%3A15514.
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Globalmodelle sind aufgrund ihres groben Gitters (60 x 60 km) nur unzureichend in der Lage kleinskalige Prozesse (orographische Niederschlagsverstärkung) in der Atmosphäre aufzulösen. Mit Mesoskalenmodellen z.B. dem GESIMA (5 x 5 km) können deshalb die
physikalische Grundlagen der Atmosphäre (Wolken- und Niederschlagsbildung) besser studiert und eine Kopplung mit hydrologischen Abflussmodellen erprobt werden. Zukünftig sieht dieses Projekt genau das vor, wobei der erste Teil, die Arbeit mit dem meteorologische Modell hier vorgestellt werden soll. Starkniederschlagserreignisse sind vielerorts auf der Welt mit charakteristischen Wetterlagen verbunden, die quasi über Tage unverändert ergiebigen Regen produzieren. Initialisiert mit den lokalen Vertikalprofilen aus Radiosondendaten, produzieren das prognostische
Mesoskalenmodell GESIMA und das diagnostische Niederschlagsberechungsverfahren (MAXRR) maximale Regenmengen vergleichbarer Größenordnung.Global models are insufficient to solve small scale atmospheric processes (e.g. orographic precipitation) due to their gross resolution (60 x 60 km). With mesoscale models e.g. the GESIMA (5 x 5 km), the physical fundamentals of the atmosphere (formation of precipitation and clouds) can better be studied and a coupling with hydrological models be tested through. This project plans exactly, as a first step, the work with the cited meteorological model. Heavy rainfall events are connected with characteristic weather conditions in many places in the world which produce invariably rain quasi over days. Initialized with the local vertical profiles from radiosonde data, the prediction model GESIMA and the diagnostic model MAXRR produced rain quantities of comparable order of magnitude.
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Splawinski, Sophie. "An assessment of freezing rain processes in the Saint- Lawrence River Valley: synoptic-dynamic analysis and operational model verification." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121459.
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Freezing rain (FZRA), a hazardous meteorological phenomenon, poses a significant threat to the general public and can severely damage societal infrastructure. The phenomenon is well known throughout the St-Lawrence River Valley (SLRV), which is known to have one of the highest frequencies of FZRA in the world owing to its orography and spatial orientation. Our focus is to provide meteorologists with the means to better predict both the onset and duration of FZRA at Montreal (CYUL), Quebec City (CYQB), and Massena (KMSS) in a two-stage process: by introducing a new 2-dimensional elliptic regression statistical forecast model and to assess synoptic and mesoscale conditions associated with past events. Analysis of a 27-year period, from 1979 through 2005, was conducted with a total of 99, 102, and 70 FZRA events at CYQB, CYUL, and KMSS, respectively. Our statistical analysis provides meteorologists with the POZR (probability of freezing rain): the ability to input model forecasted temperatures at two pressure levels and determine the probability of the onset of FZRA based on a 30-year climatology of northeasterly related precipitation. Synoptic-dynamic analysis of past events acknowledges the need for a high-resolution forecast model to adequately resolve mesoscale processes crucial to FZRA maintenance. Tests performed using a verification dataset (2006-2011 ZR event data) show the accuracy and feasibility of the model, which could be implemented by forecasting offices. Furthermore, synoptic-dynamic assessment of events within the verification dataset and forecast model comparison provide insight into missed forecasts, great forecasts and false alarms. Utilizing these methods could provide meteorologists with the opportunity to produce more highly accurate forecasts of both the onset and duration of freezing rain events.La pluie verglaçante (PV) est une forme de précipitation qui pose un danger non seulement pour le secteur publique mais également pour le secteur aérien. Ce phénomène est particulièrement connu dans la vallée du fleuve St. Laurent (VFSL). L'orientation de la vallée ainsi que l'orographie explique ce nombre accru d'évènement. Le but vise est donc de fournir aux météorologues les outils nécessaires pour améliorer les prévisions de durée et de location de PV pour les villes de Montréal (CYUL), Québec (CYQB), et Massena (KMSS). Afin d'y parvenir, deux étapes sont requises : la première, introduire un nouveau modèle statistique de prévision et la deuxième, évaluer les conditions synoptiques et meso-échelle des évènements au cours des 27 dernières années. Pendant cette période, 99, 102, et 70 évènements de PV se sont produit à CYQB, CYUL, et KMSS, respectivement. Notre analyse statistique fourni aux météorologues une probabilité d'occurrence de PV (POZR). L'analyse est un moyen d'introduire les prévisions de température à deux différents niveaux et déterminer la probabilité de PV en utilisant un modèle baser sur les données provenant d'une climatologie de précipitations et de vents dans la VFSL. Les analyses synoptiques et dynamiques des évènements passés nous ont montré la nécessité d'incorporer un modèle de prévisions à haute résolution dans la vallée; nécessaire pour résoudre adéquatement l'orographie. Ceci est impératif pour la réussite de prévisions de PV. Ensuite, en utilisant un ensemble de données de vérification, on effectues des analyses de faisabilité et de précision du modèle, ce qui peut être utilise dans un bureau de prévisions. Finalement, une comparaison d'évènements de POZR variées démontre les forces et faiblesses dans les modèles de prévisions actuels. Ces derniers, couplés avec un nouveau modèle de prévision de PV, fourni au météorologues une opportunité de produire des prévisions de PV plus précises dans la VFSL.
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Rodgers, William N. "Land Cover Change and its Impacts on a Flash Flood-Producing Rain Event in Eastern Kentucky." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1363.
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Eastern Kentucky is a 35-county region that is a part of the Cumberland Plateau of the Appalachian Mountains. With mountaintop removal and associated land cover change (LCC) (primarily deforestation), it is hypothesized that there would be changes in various atmospheric boundary layer parameters and precipitation. In this research, we have conducted sensitivity experiments of atmospheric response of a significant flash flood-producing rainfall event by modifying land cover and topography. These reflect recent LCC, including mountaintop removal (MTR). We have used the Weather Research and Forecasting (WRF) model for this purpose. The study found changes in amount, location, and timing of precipitation. LCC also modified various surface fluxes, moist static energy, planetary boundary layer height, and local-scale circulation wind circulation. The key findings were the modification in fluxes and precipitation totals. With respect to sensible heat flux (H), there was an increase to bare soil (post-MTR) in comparison to pre-MTR conditions (increased elevation with no altered land cover). Allowing for growth of vegetation, the grass simulation resulted in a decrease in H. H increased when permitting the growth of forest land cover (LC) but not to the degree of bare soil. In regards to latent heat flux (LE), there was a dramatic decrease transitioning from pre-MTR to post-MTR simulations. Then with the subsequent grass and forest simulations, there was an increase in LE comparable to the pre-MTR simulation. Under pre-MTR conditions, the total precipitation was at its highest level overall. Then with the simulated loss of vegetation and elevation, there was a dramatic decrease in precipitation. With the grass LC, the precipitation increased in all areas of interest. Then forest LC was simulated allowing overall slightly higher precipitation than grass.
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Kapangaziwiri, Evison. "Revised parameter estimation methods for the Pitman monthly rainfall-runoff model." Thesis, Rhodes University, 2008. http://hdl.handle.net/10962/d1006172.
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In recent years, increased demands have been placed on hydrologists to find the most effective methods of making predictions of hydrologic variables in ungauged basins. A huge part of the southern African region is ungauged and, in gauged basins, the extent to which observed flows represent natural flows is unknown, given unquantified upstream activities. The need to exploit water resources for social and economic development, considered in the light of water scarcity forecasts for the region, makes the reliable quantification of water resources a priority. Contemporary approaches to the problem of hydrological prediction in ungauged basins in the region have relied heavily on calibration against a limited gauged streamflow database and somewhat subjective parameter regionalizations using areas of assumed hydrological similarity. The reliance of these approaches on limited historical records, often of dubious quality, introduces uncertainty in water resources decisions. Thus, it is necessary to develop methods of estimating model parameters that are less reliant on calibration. This thesis addresses the question of whether physical basin properties and the role they play in runoff generation processes can be used directly in the estimation of parameter values of the Pitman monthly rainfall-runoff model. A physically-based approach to estimating the soil moisture accounting and runoff parameters of a conceptual, monthly time-step rainfall-runoff model is proposed. The study investigates the physical meaning of the model parameters, establishes linkages between parameter values and basin physical properties and develops relationships and equations for estimating the parameters taking into account the spatial and temporal scales used in typical model applications. The estimationmethods are then tested in selected gauged basins in southern Africa and the results of model simulations evaluated against historical observed flows. The results of 71 basins chosen from the southern African region suggest that it is possible to directly estimate hydrologically relevant parameters for the Pitman model from physical basin attributes. For South Africa, the statistical and visual fit of the simulations using the revised parameters were at least as good as the current regional sets, albeit the parameter sets being different. In the other countries where no regionalized parameter sets currently exist, simulations were equally good. The availability, within the southern African region, of the appropriate physical basin data and the disparities in the spatial scales and the levels of detail of the data currently available were identified as potential sources of uncertainty. GIS and remote sensing technologies and a widespread use of this revised approach are expected to facilitate access to these data.
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Kussior, Zdeněk. "Realistický model oblohy." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2007. http://www.nusl.cz/ntk/nusl-412799.
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The paper describes a theoretical base and realization of realistic volumetric clouds visualization in an environment of real-time simulator. The first part is concerned with a meteorological background of this problem. I show international classification of ten basic cloud types including a short description and cases of occurence. The following part is concerned with an interaction between cloudiness and simulation core, which is based on the fact, that each cloud acts as a mechanical or an electromagnetic obstacle. This should be considered on some way in simulation. The next part describes technologies and practical implementations of visualization and evaluates their characteristics. Finally, the last chapter describes my implementation and tries to outline project advancement.
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GRYNSZPAN, HENRIQUE. "EXTENSION OF THE MISME AND FIMBEL MODEL FOR THE DETERMINATION OF THE CUMULATIVE DISTRIBUTION OF THE RAIN DIFFERENTIAL ATTENUATION BETWEEN TWO CONVERGING LINKS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=12458@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRONeste trabalho, desenvolveremos um modelo teórico baseado em extensão do modelo de Misme e Fimbel para a determinação da distribuição cumulativa da atenuação diferencial devida à chuva entre dois enlaces convergentes. Resultados do modelo desenvolvido serão comparados com medidas realizadas na cidade de São Paulo e no Japão. Adicionalmente, apresentaremos previsões do modelo para os efeitos das variações do ângulo entre os enlaces, assim como dos seus comprimentos, sobre a distribuição cumulativa da atenuação diferencial. Em seguida, calcularemos a indisponibilidade do enlace desejado sujeito à interferência de outro enlace convergente, indicando que a consideração da atenuação simultânea nos dois enlaces permite um dimensionamento capaz de utilizar o espectro eletromagnético de forma mais eficiente.
In this work, we will develop a theoretical model based on an extension of the Misme and Fimbel model for the determination of the cumulative distribution of the rain differential attenuation between two converging links. Results from the developed model will be compared with measurements performed in the City of São Paulo and in Japan. Additionally, we will present model predictions for the effects of variations in the angle between the links and in the path lengths on the cumulative distribution of the rain differential attenuation. Next, we will determine the unavailability of a link in the presence of interference from another converging link. It will be indicated that consideration of the possibility of simultaneous attenuation on both links leads to a more efficient use of the electromagnetic spectrum.
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Mwelwa, Elenestina Mutekenya. "The application of the monthly time step Pitman rainfall-runoff model to the Kafue River basin of Zambia." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1006171.
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This thesis presents a discussion on the study undertaken in the application of the monthly time step Pitman rainfall-runoff model to the Kafue River basin. The study constituted one of the initial steps in the capacity building and expansion of the application of hydrologic models in the southern African region for water resources assessment, one of the core areas of the Southern African FRIEND project (Flow Regimes from International Experimental Network Data). The research process was undertaken in four major stages, each stage working towards achieving the research objectives. The first stage was the preparation of spatial data which included the selection and delineation of sub-catchments and inclusion of spatial features required to run the Pitman model and transferring the spatial data into SPATSIM. The second stage was the preparation of input data, mainly rainfall, streamflow, evaporation, and water abstraction data. This information was then imported into SPATSIM, which was able to assist in the further preparation of data by assessment of the input data quality, linking of observed flows and spatial interpolation of point rainfall data to average catchment rainfall in readiness for running and calibration of the model. The third stage was the running and calibration of the Pitman model. Use was made of both the automatic calibration facility, as well as manual calibration by means of the time series graph display and analysis facility of SPATSIM. Model calibration was used to obtain the best fit and an acceptable correlation between the simulated and the observed flows and to obtain simulation parameter sets for sub-catchments and regions within the Kafue catchment. The fourth stage was the analysis and evaluation of the model results. This included verification of results over different time periods and validation and testing of parameter transfers to other catchments. This stage also included the evaluation of SPATSIM as a tool for applying the model and as a database for the processing and storage of water resources data. The study’s output includes: A comprehensive database of hydrometeorological, physical catchment characteristics, landuse and water abstraction information for the Kafue basin; calibrated Pitman model parameters for the sub-catchments within the Kafue basin; recommendations for future work and data collection programmes for the application of the model. The study has also built capacity by facilitating training and exposure to rainfall-runoff models (specifically the Pitman model) and associated software, SPATSIM. In addition, the dissemination of the results of this study will serve as an effective way of raising awareness on the application of the Pitman model and the use of the SPATSIM software within Zambia and the region. The overall Pitman model results were found to be satisfactory and the calibrated model is able to reproduce the observed spatial and temporal variations in streamflow characteristics in the Kafue River basin.
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Tancreto, Amanda E. "Comparison of Hydrologic Model Performance Statistics Using Thiessen Polygon Rain Gauge and NEXRAD Precipitation Input Methods at Different Watershed Spatial Scales and Rainfall Return Frequencies." UNF Digital Commons, 2015. http://digitalcommons.unf.edu/etd/584.
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As hydrological computer modeling software continues to increase in complexity, the need for further understanding of the value of different model input datasets becomes apparent. Frequently used precipitation model input include rain gauge data and next-generation radar–based (NEXRAD) rainfall data. Rain gauge data are usually interpolated across a model domain using various methods including the Thiessen Polygon methodology, which may be data-sparse in some areas and overly data-dense in others. However, rain gauge data are generally very easy to use in hydrologic model development, often requiring little to no data processing. NEXRAD data have the potential to improve hydrologic runoff estimates due to the increased spatial resolution of the data: but has its own issues regarding accuracy, false precipitation indications, and difficulties due to data processing. Previous studies have investigated the value of NEXRAD input versus traditional rain gauge data inputs for hydrologic studies; however, results are inconclusive as to which precipitation source provides more accurate results. Limited work has been done to compare the value of these datasets at multiple spatial scales, especially in Florida, a study area dominated by low topographic drive and sub-tropical weather. In addition, little to no research has been done regarding the value of NEXRAD versus rain gauge data inputs at different rainfall return frequencies. The proposed research will utilize a hydrological rain-runoff model (HEC-HMS) of the Upper St. Johns River Basin, Florida to compare the performance of the two precipitation data input types at various watershed spatial scales and rainfall return frequencies. Statistical analysis of the hydrological model “goodness-of-fit” results will be utilized to assess the watershed scaling and rainfall frequency requirements to xii which NEXRAD data provide little to no advantage over standard rain gauges using the Thiessen Polygon method for estimating rainfall totals across a model domain.
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Thomas, Dana Katharine. "Design and development of a unit model for integrated instruction." CSUSB ScholarWorks, 1992. https://scholarworks.lib.csusb.edu/etd-project/1050.
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Bardhipur, Seema. "Modeling the Effect of Green Infrastructure on Direct Runoff Reduction in Residential Areas." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1494345249222244.
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Kapangaziwiri, Evison. "Regional application of the Pitman monthly rainfall-runoff model in Southern Africa incorporating uncertainty." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1006178.
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Climate change and a growing demand for freshwater resources due to population increases and socio-economic changes will make water a limiting factor (in terms of both quantity and quality) in development. The need for reliable quantitative estimates of water availability cannot be over-emphasised. However, there is frequently a paucity of the data required for this quantification as many basins, especially in the developing world, are inadequately equipped with monitoring networks. Existing networks are also shrinking due mainly to shortages in human and financial resources. Over the past few decades mathematical models have been used to bridge the data gap by generating datasets for use in management and policy making. In southern Africa, the Pitman monthly rainfall-runoff model has enjoyed relatively popular use as a water resources estimation tool. However, it is acknowledged that models are abstractions of reality and the data used to drive them is imperfect, making the model outputs uncertain. While there is acknowledgement of the limitations of modelled data in the southern African region among water practitioners, there has been little effort to explicitly quantify and account for this uncertainty in water resources estimation tools and explore how it affects the decision making process. Uncertainty manifests itself in three major areas of the modelling chain; the input data used to force the model, the parameter estimation process and the model structural errors. A previous study concluded that the parameter estimation process for the Pitman model contributed more to the global uncertainty of the model than other sources. While the literature abounds with uncertainty estimation techniques, many of these are dependent on observations and are therefore unlikely to be easily applicable to the southern African region where there is an acute shortage of such data. This study focuses on two aspects of making hydrologic predictions in ungauged basins. Firstly, the study advocates the development of an a priori parameter estimation process for the Pitman model and secondly, uses indices of hydrological functional behaviour to condition and reduce predictive uncertainty in both gauged and ungauged basins. In this approach all the basins are treated as ungauged, while the historical records in the gauged basins are used to develop regional indices of expected hydrological behaviour and assess the applicability of these methods. Incorporating uncertainty into the hydrologic estimation tools used in southern Africa entails rethinking the way the uncertain results can be used in further analysis and how they will be interpreted by stakeholders. An uncertainty framework is proposed. The framework is made up of a number of components related to the estimation of the prior distribution of the parameters, used to generate output ensembles which are then assessed and constrained using regionalised indices of basin behavioural responses. This is premised on such indices being based on the best available knowledge covering different regions. This framework is flexible enough to be used with any model structure to ensure consistent and comparable results. While the aim is to eventually apply the uncertainty framework in the southern African region, this study reports on the preliminary work on the development and testing of the framework components based on South African basins. This is necessitated by the variations in the availability and quality of the data across the region. Uncertainty in the parameter estimation process was incorporated by assuming uncertainty in the physical and hydro-meteorological data used to directly quantify the parameter. This uncertainty was represented by the range of variability of these basin characteristics and probability distribution functions were developed to account for this uncertainty and propagate it through the estimation process to generate posterior distributions for the parameters. The results show that the framework has a great deal of potential but can still be improved. In general, the estimated uncertain parameters managed to produce hydrologically realistic model outputs capturing the expected regimes across the different hydro-climatic and geo-physical gradients examined. The regional relationships for the three indices developed and tested in this study were in general agreement with existing knowledge and managed to successfully provide a multi-criteria conditioning of the model output ensembles. The feedback loop included in the framework enabled a systematic re-examination of the estimation procedures for both the parameters and the indices when inconsistencies in the results were identified. This improved results. However, there is need to carefully examine the issues and problems that may arise within other basins outside South Africa and develop guidelines for the use of the framework.iText 1.4.6 (by lowagie.com)
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Guillot, Gilles. "Modélisation statistique des champs de pluie sahéliens : application à leur désagrégation spatiale et temporelle." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10226.
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La resolution couramment atteinte par les donnees pluviometriques derivees des mesures satellitales ou des sorties de modeles de circulation generale atmospherique (m. C. G. A) sur la zone sahelienne, est de l'ordre de 1 1, sur des pas de temps correspondant a la duree de vie des systemes convectifs. Ces echelles sont incompatibles avec les echelles de la modelisation hydrologique, particulierement dans cette region, ou les pluies principalement d'origine convective, presentent une forte variabilite spatiale et temporelle. Le travail presente a consiste a developper et valider un modele des champs de pluie saheliens, permettant d'utiliser l'information de grande echelle fournie par un satellite ou un m. C. G. A, pour simuler de champs de pluie a une plus haute resolution. Les bases de ce modele proviennent de l'analyse du jeu de donnees de l'experience epsat-niger. Il s'appuie sur trois composantes : (i) une representation geostatistique des champs spatiaux au pas de temps de l'evenement, (ii) un modele de la cinematique des systemes convectifs, (iii) un modele statistique a quatre parametres des hyetogrammes. Ce modele est developpe dans un cadre mathematique qui maintient une coherence entre les proprietes observees a differentes echelles. De ce fait, il peut etre utilise pour realiser des simulations conditionnees par des valeurs pluviometriques de grande echelle.
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Nobre, Andrezza Bellotto. "Chuva de sementes zoocóricas em uma floresta de Mata Atlântica em processo de restauração: caracterização e fatores de influência." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-26032013-165713/.
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Pela necessidade de reverter o atual quadro de degradação da Mata Atlântica, ações de restauração se fazem urgentes e devem ser pensadas a fim de restabelecer a biodiversidade nessas áreas, envolvendo as diversas formas de vida vegetal, animal e suas interações. O restabelecimento da relação planta-frugívoro e consequente dispersão de sementes certamente são essenciais não só para a conservação de uma floresta existente, mas também na aceleração do processo de restauração florestal. Portanto, a atração dos agentes dispersores de sementes deve fazer parte dos esforços empregados em ações restauradoras. Uma forma de avaliar a contribuição destes animais em áreas restauradas é através do estudo da chuva de sementes, mais especificamente aquela que é resultado dos eventos de dispersão pela fauna (zoocoria). Este estudo buscou caracterizar e comparar a composição da chuva de sementes zoocóricas em uma área em processo de restauração florestal na Mata Atlântica, submetidas a duas técnicas de manejo distintas, uma por meio de plantio de restauração em área total e outra, através da indução e condução da regeneração natural, originando uma área de capoeira. Ainda, utilizando a ferramenta de seleção de modelos pelo critério de Akaike, foram avaliadas se variáveis de estrutura e composição da vegetação arbustivo-arbórea influenciaram a riqueza e abundância da chuva de sementes zoocóricas total e imigrantes. O estudo foi conduzido em uma área em processo de restauração florestal, com seis anos de idade, que abrange 28,86 ha da Fazenda Intermontes (24°11\'17\" S, 42°24\'49\" O; 24°12\'47\" S, 42° 26\'15\" O), próximo ao município de Ribeirão Grande, SP. Propágulos depositados nos coletores foram retirados mensalmente pelo período de 1 ano. Utilizou-se um total de 100 coletores de sementes, de 1 m x 1 m. Para a caracterização da vegetação presente, foi realizado um levantamento dos indivíduos arbustivo-arbóreos, num raio de 5 metros no entorno de cada coletor de semente. Os resultados mostraram que a composição da comunidade da chuva de sementes zoocóricas diferiu entre os ambientes de capoeira e plantio, porém a riqueza e abundância médias das sementes não diferiram significativamente entre os ambientes. Apesar da composição da comunidade ter sido diferente, as categorias funcionais das sementes presentes na chuva, em ambas as áreas, foram semelhantes entre si. Avaliando se houve influência de variáveis relacionadas à estrutura e composição da vegetação arbustivo-arbórea na chuva de sementes zoocóricas, os modelos gerados e selecionados indicaram que as variáveis estudadas não influenciaram a riqueza e abundância da chuva de sementes zoocóricas total e imigrantes. O estudo concluiu também que o processo de chegada de propágulos alóctones a área já se iniciou, demonstrando um grande potencial de incremento de novas espécies, pertencentes a outras formas de vida e a diferentes funções ecológicas. Isto possibilita a aceleração do processo de restauração florestal, aumento da complexidade estrutural da vegetação e uma contribuição para a heterogeneidade da floresta implantada, fator este importante para o processo de retorno e incremento da fauna dispersora.The need to reverse the current degradation of the Atlantic Forest requires urgent restoration actions aimed at reestablishing biodiversity in these areas, involving various plant and animal life forms and their interactions. The reestablishment of plant-frugivore interactions and subsequent seed dispersal are essential not only for the conservation of an existing forest, but also for the acceleration of forest restoration processes. Therefore, seed dispersal agents should be employed in restoration actions. One way to assess animals\' contribution in seed dispersion is through the study of seed rain, more specifically through results of dispersal events by fauna (zoochory). This study aimed to characterize and compare the composition of animal-dispersed seed rain in an area of the Atlantic Forest undergoing a restoration process using two different management techniques. One area comprised of tree planting and another comprising a \"capoeira\" through assisted natural regeneration. We also used an Akaike information criterion of model selection tool to evaluate whether structure and composition variables of arbustive-arboreal vegetation influenced the richness and abundance of total and immigrant animal-dispersed seed rain. The study was conducted in an area undergoing a forest restoration process with six years of age, covering 28.86 ha of the Intermontes Farm (24°11\'17\"S, 42°24\'49\"W; 24°12\'47\"S, 42°26\'15\"W), near Ribeirão Grande city, São Paulo State, Brazil. Propagules deposited in traps were removed monthly for a period of one year. We used 100 seed collectors 1 m x 1 m. To characterize the vegetation in the region, we surveyed the arbustive-arboreal species in a 5-meter radius around each seed collector. The results showed that the community composition of the animal-dispersed seed rain differed between tree planting and \"capoeira\" environments; however, the richness and abundance averages of seeds did not differ significantly between the environments. Although the community composition was different, functional categories of seeds in the rain in both areas were similar. Assessing whether there was influence of variables related to structure and composition of arbustive-arboreal species on animal-dispersed seed rain, generated and selected models indicated that these variables did not influence the richness and abundance of total and immigrant animal-dispersed seed rain. The results also showed the presence of alien propagules in the region, demonstrating great potential for the growth of new species belonging to other life forms with different ecological functions. This allows the acceleration of forest restoration processes, increased structural complexity of vegetation and contribution to heterogeneity of deployed forest, which is important for the return and increase of animal dispersers.
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Vismara, Edgar de Souza. "Mensuração da biomassa e construção de modelos para construção de equações de biomassa." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-18052009-155116/.
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O interesse pela quantificação da biomassa florestal vem crescendo muito nos últimos anos, sendo este crescimento relacionado diretamente ao potencial que as florestas tem em acumular carbono atmosférico na sua biomassa. A biomassa florestal pode ser acessada diretamente, por meio de inventário, ou através de modelos empíricos de predição. A construção de modelos de predição de biomassa envolve a mensuração das variáveis e o ajuste e seleção de modelos estatísticos. A partir de uma amostra destrutiva de de 200 indivíduos de dez essências florestais distintas advindos da região de Linhares, ES., foram construídos modelos de predição empíricos de biomassa aérea visando futuro uso em projetos de reflorestamento. O processo de construção dos modelos consistiu de uma análise das técnicas de obtenção dos dados e de ajuste dos modelos, bem como de uma análise dos processos de seleção destes a partir do critério de Informação de Akaike (AIC). No processo de obtenção dos dados foram testadas a técnica volumétrica e a técnica gravimétrica, a partir da coleta de cinco discos de madeira por árvore, em posições distintas no lenho. Na técnica gravimétrica, estudou-se diferentes técnicas de composição do teor de umidade dos discos para determinação da biomassa, concluindo-se como a melhor a que utiliza a média aritmética dos discos da base, meio e topo. Na técnica volumétrica, estudou-se diferentes técnicas de composição da densidade do tronco com base nas densidades básicas dos discos, concluindo-se que em termos de densidade do tronco, a média aritmética das densidades básicas dos cinco discos se mostrou como melhor técnica. Entretanto, quando se multiplica a densidade do tronco pelo volume deste para obtenção da biomassa, a utilização da densidade básica do disco do meio se mostrou superior a todas as técnicas. A utilização de uma densidade básica média da espécie para determinação da biomassa, via técnica volumétrica, se apresentou como uma abordagem inferior a qualquer técnica que utiliza informação da densidade do tronco das árvores individualmente. Por fim, sete modelos de predição de biomassa aérea de árvores considerando seus diferentes compartimentos foram ajustados, a partir das funções de Spurr e Schumacher-Hall, com e sem a inclusão da altura como variável preditora. Destes modelos, quatro eram gaussianos e três eram lognormais. Estes mesmos sete modelos foram ajustados incluindo a medida de penetração como variável preditora, totalizando quatorze modelos testados. O modelo de Schumacher-Hall se mostrou, de maneira geral, superior ao modelo de Spurr. A altura só se mostrou efetiva na explicação da biomassa das árvores quando em conjunto com a medida de penetração. Os modelos selecionados foram do grupo que incluíram a medida de penetração no lenho como variável preditora e , exceto o modelo de predição da biomassa de folhas, todos se mostraram adequados para aplicação na predição da biomassa aérea em áreas de reflorestamento.Forest biomass measurement implies a destructive procedure, thus forest inventories and biomass surveys apply indirect procedure for the determination of biomass of the different components of the forest (wood, branches, leaves, roots, etc.). The usual approch consists in taking a destructive sample for the measurment of trees attributes and an empirical relationship is established between the biomass and other attributes that can be directly measured on standing trees, e.g., stem diameter and tree height. The biomass determination of felled trees can be achived by two techniques: the gravimetric technique, that weights the components in the field and take a sample for the determination of water content in the laboratory; and the volumetric technique, that determines the volume of the component in the field and take a sample for the determination of the wood specific gravity (wood basic density) in the laboratory. The gravimetric technique applies to all components of the trees, while the volumetric technique is usually restricted to the stem and large branches. In this study, these two techniques are studied in a sample fo 200 trees of 10 different species from the region of Linhares, ES. In each tree, 5 cross-sections of the stem were taken to investigate the best procedure for the determination of water content in gravimetric technique and for determination of the wood specific gravity in the volumetric technique. Also, Akaike Information Criterion (AIC) was used to compare different statistical models for the prediction o tree biomass. For the stem water content determination, the best procedure as the aritmetic mean of the water content from the cross-sections in the base, middle and top of the stem. In the determination of wood specific gravity, the best procedure was the aritmetic mean of all five cross-sections discs of the stem, however, for the determination of the biomass, i.e., the product of stem volume and wood specific gravity, the best procedure was the use of the middle stem cross-section disc wood specific gravity. The use of an average wood specific gravity by species showed worse results than any procedure that used information of wood specific gravity at individual tree level. Seven models, as variations of Spurr and Schumacher-Hall volume equation models, were tested for the different tree components: wood (stem and large branches), little branches, leaves and total biomass. In general, Schumacher-Hall models were better than Spurr based models, and models that included only diameter (DBH) information performed better than models with diameter and height measurements. When a measure of penetration in the wood, as a surrogate of wood density, was added to the models, the models with the three variables: diameter, height and penetration, became the best models.
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Morokawa, Tokitika. "Modelagem da din?mica de crescimento de uma Floresta Ombr?fila aerta do estado de Rond?nia." Universidade Federal Rural do Rio de Janeiro, 2009. https://tede.ufrrj.br/jspui/handle/tede/490.
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Previous issue date: 2009-02-05A model of the growth dynamics of forests was developed applying Bertalanffy growth model (BGM) y=a[(1 e bt)c] for individual trees. Based on linearized relationship with diameter and height equation LnH=b0+LnD and volume equation V=b0Db1Hb2 mutually compatible equations for diameter, basal area, height and volume were generated, adjusting parameters a and c of BGM. Additionally, it was developed a methodology based on DBH measurements in two occasions and the estimate value of parameter a to get the values of parameter c and b of BGM. The data of the inventory of 1,061 trees over 40cm DBH of 67.5 hectares of tropical rain forest of Aquariquara Extractive Reserve, located in State of Rondonia, Brazil, were used to test the developed model. These data were grouped in nine maximum diameter (Dmax) classes. The tree survival was estimated based on the frequency of trees by relative age class. The input and output of each tree was adjusted considering a closed and stable population with replacement of a dead tree by the ingrowth of the same specie of tree with 40cm DBH. Applying the model to such data and simulating the growth dynamics of the forest in a time frame of 1500 years (T1 → 1,500), the difference of simulated annual average, in relation to the observed values in the year T0 of the forest inventory was -2.09% in age, -0.33% in height, -0.96% in diameter, -3.41% in basal area, -3.81% in volume and +1.81% in merchantable trees value. The average values of T1→500, T501→1000 and T1001→1500 periods were equal for all variables by Kruskal-Wallis test (p=0.05). The simulation showed that one hectare of this forest maintains a total stock composed of 15.72 120-year-old trees, accumulated 4.35m2 of basal area and 37.98m3 wood volumes on average. The annual input flow of the system was 0.3457 88-year-old trees which accumulated 0.0441m2 of basal area and volume of 0.3265m3. The output of the system consists of 0.3459 132-year-old trees totaling 0,1127m2 of basal area and 0.9911m3 in volume. The annual input and output rates were, respectively, 2.20 and 2.20% in number of trees, 1.01 and 2.59% in basal area and 0.86 and 2.61% in volume. In addition, the simulation indicated that it is possible to sustain an average annual production of 0.5528m3 of merchantable timber generating R$5.50 (about US$1.49) annual income per hectare of forest. The simulation showed that the model developed describes growth dynamics of tropical forest. However, it needs to be properly adjusted based on real growth of each individual tree and flows of input and output of trees in the system.
Nesta tese foi desenvolvida a modelagem da din?mica de crescimento de uma floresta, aplicando-se o modelo de crescimento de Bertalanffy (MCB) y=a[(1 e bt)c] para ?rvores individuais. Baseando-se nas rela??es linearizadas entre o di?metro e altura da equa??o LnH=b0+LnD e do di?metro com volume V=b0Db1Hb2 foram geradas equa??es de crescimento reciprocamente compat?veis entre di?metro, ?rea basal, altura e volume, ajustando-se os valores dos coeficientes a e c do MCB. Adicionalmente, foi desenvolvida metodologia, baseando-se em medi??es de DAP de cada ?rvore em duas ocasi?es e com a estimativa do coeficiente a, para obter os valores dos coeficientes c e b do MCB. Para testar o modelo desenvolvido foram utilizados numa simula??o os dados de invent?rio de 1.061 ?rvores, com DAP≥40cm, de uma ?rea de 67,5ha de Floresta Omb?fila Aberta da Reserva Extrativista Aquariquara, localizada no munic?pio de Machadinho D?Oeste, estado de Rond?nia. Estes dados foram agrupados em nove classes de di?metro m?ximo (Dmax) compreendidas entre 50 e 240cm, mantendo-se uma amplitude entre elas de 10cm. A taxa de sobreviv?ncia da ?rvore foi estimada baseando-se na freq??ncia de ?rvores por classe de idade relativa. O sistema de entrada (input) e sa?da (output) de cada ?rvore foi ajustado considerando uma popula??o fechada e est?vel com substitui??o de uma ?rvore morta pela entrada de ?rvore da mesma esp?cie com DAP≥40cm. Em rela??o aos valores observados no ano T0 do invent?rio florestal, as m?dias anuais dos valores simulados da din?mica de crescimento dessa floresta num horizonte temporal de 1.500 anos (T1→1.500), apresentaram diferen?as m?dias de -2,09% em idade, -0,33% em altura, -0,96% em di?metro, -3,41% em ?rea basal, -3,81% em volume e +1,81% em valor da ?rvore em p?. As m?dias anuais dos valores simulados dos per?odos T1→500, T501→1.000 e T1.001→1.500 foram iguais para todas as vari?veis pelo teste de repetibilidade de Kruskal-Wallis (p=0,05), mostrando que o modelo ? est?vel no tempo. A simula??o mostrou que esta floresta mantem em m?dia um estoque total de massa em crescimento composta de 15,72 ?rvores.ha-1 com 120 anos de idade acumulando um total de 4,35m2.ha-1 de ?rea basal e 37,98m3.ha-1 de volume de madeira. O fluxo anual de ingresso no sistema foi de 0,3457 ?rvores com 88 anos de idade que somaram 0,0441m2 de ?rea basal e 0,3265m3 de volume, e de sa?da do sistema composto de 0,3459 ?rvores com 132 anos de idade que somaram 0,1127m2 de ?rea basal e 0,9911m3 de volume por hectare, resultando em taxas de ingressos e sa?das anuais, respectivamente, de 2,20 e 2,20% em n?mero de ?rvores, 1,01 e 2,59% em ?rea basal e 0,86 e 2,61% em volume. Al?m disso, a simula??o indicou que ? poss?vel sustentar uma produ??o m?dia anual de 0,5528m3 de madeira de valor comercial gerando renda anual de R$5,50 por hectare (a pre?o corrente de outubro de 2002) de floresta. A simula??o mostrou que o modelo desenvolvido descreve a din?mica de crescimento de floresta tropical, por?m ele necessita ser devidamente calibrado tomando os dados de crescimento real de cada ?rvore individual e dos fluxos de ingressos e sa?das de ?rvores do sistema.
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Chapman, Michael Alan. "Measuring the Effectiveness of a Green Infrastructure Pilot Program in Wyoming, Ohio." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1323547160.
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Acheampong, Josephine. "Green Financing: Financing Circular Economy Companies : Case Studies of Ragn-Sellsföretagen AB and Inrego AB." Thesis, KTH, Entreprenörskap och Innovation, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188677.
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The circular economy (CE) has been identified as a catalyst in sustainable development and economic growth that has the potential to move society from the traditional linear model of resource consumption in the form of take-make-waste to an innovative circular model in the form of reduce-reuse-recycle. Transitioning from the linear economy to the CE requires changes in four areas: material and product design, business models, global reverse networks and enabling business environments. This study considers the financing needs of CE companies as a result of business model changes. Through the case studies of Ragn-Sellsföretagen AB and Inrego AB, analysed with secondary data from ING Bank and primary data collected through semi-structured interviews with the case companies, this research sheds more light on the financing needs of circular economy companies and how they are financed. Findings from this research suggest that the financing needs of circular economy companies depend on the value proposition of the company. In accordance with the pecking order of capital structure, all financing needs of the companies studied are financed from internal sources, particularly retained earnings before external debt financing is accessed. Findings indicate the willingness of banks to finance circular economy companies. The results of this research suggest that the circular economy companies studied do not need financial support from the government or its agencies to succeed even though favourable laws are welcomed. They report that their long-term success depends on their ability to remain innovative in their business models, aligning with Schumpeter’s creative destruction model.
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Au, Siu-fung, and 區兆峯. "Inter-modal co-ordination of West Rail with other public transport modes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30123811.
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Knies, Alberto Eduardo. "Estimativa do escoamento superficial em diferentes níveis de dossel vegetativo e cobertura do solo." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/3612.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoThe soil tillage systems modify its water balance and for the correct irrigation management is fundamental to determining the runoff and effective rainfall, which helps to maximize the use of rainwater and minimizes the use of supplemental irrigation. The objective of this study was to determine, model and estimate the runoff and the effective rainfall during the development cycle of the common black bean and maize in soil with and without straw on the surface, in different land slope and rainfall intensities simulated, using the field experiments, multivariate equations, the Curve Number Method (CN) and the SIMDualKc Model. Two experiments were conducted in the field with crops of black beans and maize, where different intensities of simulated rainfall (35, 70 and 105 mm h-1) were applied at different times of the crop cycle (soil cover of 0, 28, 63 and 100% by the canopy beans; 0, 30, 72 and 100% by canopy of maize) and distinct land slope (1, 5 and 10%) in soil without and with (5 Mg ha-1) of oat straw on the surface. The runoff values observed were compared with those estimated by the CN method, suggesting new values of CN to improve the estimate. From the set of data collected from the field analysis of multiple linear regression to estimate runoff and simulations with SIMDualKc model to estimate runoff and effective rainfall were performed. The start time of the runoff, constant runoff rate, total runoff and the percentage of runoff in relation to the volume of rain were little influenced by the crops of beans and maize. Reductions in runoff were provided by the straw on the soil surface within 45 and 48% for the crops beans and maize, respectively. The CN method for the bean crop underestimated runoff by up to 10% for the soil without straw on the surface, and overestimated by up to 17% for the soil with straw. For maize, the method overestimated the runoff by up 32.4% in soil with straw and 12% in soil without straw. To improve estimation the CN, new values are proposed for CN, considering the crop, the presence or absence of straw on soil surface and intensity rain. The use of multiple linear regression analyzes indicated that the volume of precipitation (R2=0.52) and soil cover by straw (R2=0.18) are the variables with the greatest influence on runoff. Four multiple equations were generated, and the equation 2, whose input parameters are the volume of rain and amount of litter on the soil surface, was presented the best estimate of the runoff of a data set than the one that gave its origin. The SIMDualKc Model requires adjustments to estimate runoff and effective rainfall during the crop cycle of beans and maize, so consider the benefits of straw on the soil surface in reducing runoff. Thus, the suggested value of CN (CN=75) was changed to 71 and 87 to the black bean crop, and 56 and 79 for the maize crop for the soil with and without straw on the surface, respectively.
Os sistemas de manejo do solo modificam o seu balanço hídrico e para o correto manejo da irrigação é de fundamental importância a determinação do escoamento superficial e da chuva efetiva, o que contribui para maximizar o uso da água das chuvas e minimiza a utilização de irrigação suplementar. O objetivo do presente trabalho foi determinar, modelar e estimar o escoamento superficial e a chuva efetiva durante o ciclo de desenvolvimento das culturas do feijão e milho, cultivados em solo com e sem palha na superfície, em diferentes declividade do terreno e intensidades de chuvas simuladas, utilizando experimentos a campo, equações multivariadas, o método Curva Número (CN) e o modelo SIMDualKc. Foram realizados dois experimentos à campo, com as culturas do feijão e milho, em que foram aplicadas diferentes intensidades de chuvas simuladas (35, 70 e 105 mm h-1), em diferentes momentos do ciclo das culturas (cobertura do solo de 0, 28, 63 e 100% pelo dossel vegetativo do feijão; 0, 30, 72 e 100% pelo dossel vegetativo do milho) e distintas declividade do terreno (1, 5 e 10%), em solo sem e com (5 Mg ha-1) palha de aveia preta na superfície. Os valores de escoamento superficial observados foram comparados com os estimados pelo método CN, sugerindo-se novos valores de CN para melhorar a estimativa. A partir do conjunto de dados coletados a campo, foram realizadas análises de regressão linear múltiplas para a estimativa do escoamento superficial e, simulações com o modelo SIMDualKc para estimativa do escoamento superficial e da chuva efetiva. O tempo de início do escoamento, a taxa constante de escoamento, o escoamento total e a porcentagem de escoamento em relação ao volume da chuva foram pouco influenciados pelo crescimento do dossel vegetativo das plantas de feijão e milho. Reduções no escoamento superficial foram proporcionadas pela presença de palha na superfície do solo, em até 45 e 48% para as culturas do feijão e milho, respectivamente. O método CN para a cultura do feijão subestimou o escoamento superficial em até 10% para o solo sem palha na superfície e, superestimou em até 17% para o solo com palha. Para a cultura do milho, o método CN superestimou o escoamento superficial em até 32,4% no solo com palha e 12% no solo sem palha. Para melhorar a estimativa do método CN, foram propostos novos valores de CN, considerando a cultura, a presença ou não de palha na superfície do solo e a intensidade da chuva. A utilização de análises de regressão linear múltiplas indicaram que o volume da chuva (R2=0,52) e a cobertura do solo por palha (R2=0,18) são as variáveis com maior influência sobre o escoamento superficial. Foram geradas quatro equações múltiplas, sendo que a equação 2, cujos parâmetros de entrada são o volume da chuva e quantidade de palha na superfície do solo, foi a que apresentou a melhor estimativa do escoamento superficial de um conjunto de dados diferente daquele que lhe deu origem. O modelo SIMDualKc necessita de ajustes para estimar o escoamento superficial e a chuva efetiva durante o ciclo das culturas de feijão e milho, de modo que considere os benefícios da palha na superfície do solo na redução do escoamento superficial. Desta forma, o valor sugerido de CN (CN=75) foi alterado para 71 e 87 para a cultura do feijão e, 56 e 79 para a cultura do milho, para o solo com e sem palha na superfície, respectivamente.
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Bottomley, Gregory Edward. "Modeling the dynamic behavior of rain attenuation." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/90918.
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This thesis addresses the problem of predicting satellite path rain fade duration statistics for an arbitrary location, frequency, elevation angle and polarization. It summarizes the development of a dynamic stochastic model. From this model a technique is derived for predicting fade duration statistics for one site using measured attenuation data at another site. This technique is evaluated by comparing predicted and experimental results for several locations, frequencies, elevation angles and polarizations.M.S.