Dissertations / Theses on the topic 'Normalized Difference Water Index'
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Minas, Michael Getachew. "Characterization of plant-water interaction in Kilombero River Catchment in Tanzania using Normalized Difference Vegetation Index (NDVI)." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-110913.
Full textNeff, Kirstin Lynn. "Seasonality of Groundwater Recharge in the Basin and Range Province, Western North America." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/556969.
Full textGuo, Qi. "Bangladesh Shoreline Changes During the Last Four Decades Using Satellite Remote Sensing Data." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503258115717912.
Full textMuche, Muluken Eyayu. "Surface water hydrologic modeling using remote sensing data for natural and disturbed lands." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32609.
Full textDepartment of Biological & Agricultural Engineering
Stacy L. Hutchinson
The Soil Conservation Service-Curve Number (SCS-CN) method is widely used to estimate direct runoff from rainfall events; however, the method does not account for the dynamic rainfall-runoff relationship. This study used back-calculated curve numbers (CNs) and Normalized Difference Vegetation Index (NDVI) to develop NDVI-based CNs (CN[subscript]NDV) using four small northeastern Kansas grassland watersheds with average areas of 1 km² and twelve years (2001–2012) of daily precipitation and runoff data. Analysis indicated that the CN[subscript]NDVI model improved runoff predictions compared to the SCS-CN method. The CN[subscript]NDVI also showed greater variability in CNs, especially during growing season, thereby increasing the model’s ability to estimate relatively accurate runoff from rainfall events since most rainfall occurs during the growing season. The CN[subscript]NDVI model was applied to small, disturbed grassland watersheds to assess the model’s ability to detect land cover change impact for military maneuver damage and large, diverse land use/cover watersheds to assess the impact of scaling up the model. CN[subscript]NDVI application was assessed using a paired watershed study at Fort Riley, Kansas. Paired watersheds were identified through k-means and hierarchical-agglomerative clustering techniques. At the large watershed scale, Daymet precipitation was used to estimate runoff, which was compared to direct runoff extracted from stream flow at gauging points for Chapman (grassland dominated) and Upper Delaware (agriculture dominated) watersheds. In large, diverse watersheds, CN[subscript]NDVI performed better in moderate and overall flow years. Overall, CN[subscript]NDVI more accurately simulated runoff compared to SCS-CN results: The calibrated model increased by 0.91 for every unit increase in observed flow (r = 0.83), while standard CN-based flow increased by 0.506 for every unit increase in observed flow (r = 0.404). Therefore, CN[subscript]NDVI could help identify land use/cover changes and disturbances and spatiotemporal changes in runoff at various scales. CN[subscript]NDVI could also be used to accurately estimate runoff from precipitation events in order to instigate more timely land management decisions.
Roberson, Travis Leon. "Improving Soil Moisture Assessment of Turfgrass Systems Utilizing Field Radiometry." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/87391.
Full textMaster of Science in Life Sciences
Managed turfgrasses provide several benefits including filtering pollutants, cooling their surroundings, generating oxygen, preventing erosion, serving as recreational surfaces, and increasing landscape aesthetics. Intensively managed turfgrass systems, such as on golf courses and sports fields, require more inputs to maintain acceptable conditions. Freshwater use is often excessive on intensively managed turfgrasses to maintain proper plant growth. Drought conditions often limit water availability, especially in regions with limited rainfall. Turf managers tend to over-apply water across large acreage when few localized areas begin to show symptoms of drought. Additionally, turf managers sometimes wrongly identify stressed areas from other factors as ones being moisture-deprived. Advancements such as the use of soil moisture meters have simplified irrigation decisions as an aid to visual inspections for drought stress. While this method enhances detection accuracy, it still provides no solution to increase efficiency. Expanding our current knowledge of turfgrass canopy light reflectance for rapid moisture stress identification can potentially save both time and water resources. The objective of this research was to enhance our ability to identify and predict moisture stress of creeping bentgrass (CBG) and hybrid bermudagrass (HBG) canopies integrated into varying soil textures (USGA 90:10 sand (S), sand loam (SL) and Clay (C)) using light reflectance measurements. Dry-down cycles were conducted under greenhouses conditions collecting soil moisture and light reflectance data every hour from 7 am to 7 pm after saturating and withholding water from established plugs. Moisture stress was most accurately estimated over time using two vegetation indices, the water band index (WBI) and green-to-red ratio index (GRI), with approximately ninety percent accuracy to visible wilt stress. The WBI and GRI predicted moisture stress of CBG in all soil types and HBG in SL and C approximately 14 hours before the grasses reached 50% wilt. While light reflectance varies on exposed soils, our research shows that underlying soils do not interfere with measurements across typical turfgrass stands. This research provides a foundation for future research implementing rapid, aerial measurements of moisture stressed turfgrasses on a broad application of CBG and HBG on constructed or native soils.
Andersson, Jafet. "Land Cover Change in the Okavango River Basin : Historical changes during the Angolan civil war, contributing causes and effects on water quality." Thesis, Linköping University, Department of Water and Environmental Studies, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7152.
Full textThe Okavango river flows from southern Angola, through the Kavango region of Namibia and into the Okavango Delta in Botswana. The recent peace in Angola hopefully marks the end of the intense suffering that the peoples of the river basin have endured, and the beginning of sustainable decision-making in the area. Informed decision-making however requires knowledge; and there is a need for, and a lack of knowledge regarding basin-wide land cover (LC) changes, and their causes, during the Angolan civil war in the basin. Furthermore, there is a need for, and a lack of knowledge on how expanding large-scale agriculture and urban growth along the Angola-Namibia border affects the water quality of the river.
The aim of this study was therefore to develop a remote sensing method applicable to the basin (with scant ground-truth data availability) to carry out a systematic historic study of LC changes during the Angolan civil war, to apply the method to the basin, to relate these changes to major societal trends in the region, and to analyse potential impacts of expanding large-scale agriculture and urban growth on the water quality of the river along the Angola-Namibia border.
A range of remote sensing methods to study historic LC changes in the basin were tried and evaluated against reference data collected during a field visit in Namibia in October 2005. Eventually, two methods were selected and applied to pre-processed Landsat MSS and ETM+ satellite image mosaics of 1973 and 2001 respectively: 1. a combined unsupervised classification and pattern-recognition change detection method providing quantified and geographically distributed binary LC class change trajectory information and, 2. an NDVI (Normalised Difference Vegetation Index) change detection method providing quantified and geographically distributed continuous information on degrees of change in vegetation vigour. In addition, available documents and people initiated in the basin conditions were consulted in the pursuit of discerning major societal trends that the basin had undergone during the Angolan civil war. Finally, concentrations of nutrients (total phosphorous & total nitrogen), bacteria (faecal coliforms & faecal streptococci), conductivity, total dissolved solids, dissolved oxygen, pH, temperature and Secchi depth were sampled at 11 locations upstream and downstream of large-scale agricultural facilities and an urban area during the aforementioned field visit.
The nature, extent and geographical distribution of LC changes in the study area during the Angolan civil war were determined. The study area (150 922 km2) was the Angolan and Namibian parts of the basin. The results indicate that the vegetation vigour is dynamic and has decreased overall in the area, perhaps connected with precipitation differences between the years. However while the vigour decreased in the northwest, it increased in the northeast, and on more local scales the pattern was often more complex. With respect to migration out of Angola into Namibia, the LC changes followed expectations of more intense use in Namibia close to the border (0-5 km), but not at some distance (10-20 km), particularly east of Rundu. With respect to urbanisation, expectations of increased human impact locally were observed in e.g. Rundu, Menongue and Cuito Cuanavale. Road deterioration was also observed with Angolan urbanisation but some infrastructures appeared less damaged by the war. Some villages (e.g. Savitangaiala de Môma) seem to have been abandoned during the war so that the vegetation could regenerate, which was expected. But other villages (e.g. Techipeio) have not undergone the same vegetation regeneration suggesting they were not abandoned. The areal extent of large-scale agriculture increased 59% (26 km2) during the war, perhaps as a consequence of population growth. But the expansion was not nearly at par with the population growth of the Kavango region (320%), suggesting that a smaller proportion of the population relied on the large-scale agriculture for their subsistence in 2001 compared with 1973.
No significant impacts were found from the large-scale agriculture and urbanisation on the water quality during the dry season of 2005. Total phosphorous concentrations (with range: 0.067-0.095 mg l-1) did vary significantly between locations (p=0.013) but locations upstream and downstream of large-scale agricultural facilities were not significantly different (p=0.5444). Neither did faecal coliforms (range: 23-63 counts per 100ml) nor faecal streptococci (range: 8-33 counts per 100ml) vary significantly between locations (p=0.332 and p=0.354 respectively). Thus the impact of Rundu and the extensive livestock farming along the border were not significant at this time. The Cuito river on the other hand significantly decreased both the conductivity (range: 27.2-49.7 μS cm-1, p<0.0001) and the total dissolved solid concentration (range: 12.7-23.4 mg l-1, p<0.0001) of the mainstream of the Okavango during the dry season.
Land cover changes during the Angolan civil war, contributing causes and effects on water quality were studied in this research effort. Many of the obtained results can be used directly or with further application as a knowledge base for sustainable decision-making and management in the basin. Wisely used by institutions charged with that objective, the information can contribute to sustainable development and the ending of suffering and poverty for the benefit of the peoples of the Okavango and beyond.
Pinheiro, Ana T. (Ana Torres) 1972. "Relationship between satellite-derived Normalized Difference Vegetation Index (NDVI) and surface hydrology." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46149.
Full textGriffin, Alicia Marie Rutledge. "Using LiDAR and normalized difference vegetation index to remotely determine LAI and percent canopy cover at varying scales." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1117.
Full textAbbasova, Tahira. "Detection and analysis of changes in desertification in the Caspian Sea Region." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-43241.
Full textOsunmadewa, Babatunde A., Christine Wessollek, and Pierre Karrasch. "Linear and segmented linear trend detection for vegetation cover using GIMMS normalized difference vegetation index data in semiarid regions of Nigeria." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35266.
Full textUpadhaya, Suraj. "Use of Landsat Data to Characterize Burn Severity, Forest Structure and Invasion by Paulownia (Paulownia Tomentosa) in an Eastern Deciduous Forest, Kentucky." UKnowledge, 2015. http://uknowledge.uky.edu/forestry_etds/23.
Full textFonnesbeck, Brook B. "Digital Soil Mapping Using Landscape Stratification for Arid Rangelands in the Eastern Great Basin, Central Utah." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4525.
Full textJesus, Bruna Luiza Pereira de. "A relação entre a temperatura radiométrica de superfície (Land Surface Temperature-LST), índice de vegetação (Normalizes Diference Vegetation Index-NDVI) e os diferentes padrões de uso da terra do município de São Paulo." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/8/8135/tde-11012016-143102/.
Full textThis study aims to understand the relationship between Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) and the patterns of land use in the municipality of São Paulo, from 1985 to 2010. A totoal of 45 random samples were extracted from the 15 districts used in this study, with different patterns of land use which were subdivided into three different clases: low-end, middle and middle-high. Geospatial approaches allowed the extraction of satellite image data from Landsat 5 data (TM) and from Orthophotos from 2010. The behavior of the samples varied accordingly to the different group profiles. The low-end group presented the highest thermal amplitudes and more significant absence of urban vegetation linked, both to low urbanization and construction standards. The average standard group is characterized by the predominance of vertical buildings and lacks urban trees amidst a consolidated urban landscape. The average-high standard group displayed the highest concentration of green urban areas, distributed homogeneously in most samples, so this group presented low variations both in temperature amplitude and in the Normalized Difference Vegetation Index (NDVI). The correlation tests showed strong negative correlations between samples of Land Surface Temperature (LST) and the NDVI samples, of -0.58 in 1985, -0.43 in 2004 and -0.82 in 2010. Understanding the relations between the different patterns of land use, surface temperature and the NDVI (with due concern for environmental planning) is an important step in the identification and rehabilitation of enviromentally. This research is part of the Thematic Project FAPESP 08/58161 -1 process, \"Assessment of Impacts and Vulnerability to Climate Change in Brazil and strategies for Adaptation options\", Component 5: Vulnerability of the metropolitan region of São Paulo to climate Change.
Bradford, Jessica. "Examining Culex tarsalis (Diptera: Culicidae) population changes with satellite vegetation index data." Kansas State University, 2014. http://hdl.handle.net/2097/17139.
Full textDepartment of Diagnostic Medicine/Pathobiology
Michael W. Sanderson
A zoonotic disease is any disease or infection that is naturally transmissible from vertebrate animals to humans. Over 200 zoonoses have been described (Zoonoses and the Human-Animal-Ecosystems Interface, 2013). Many zoonotic viruses are arboviruses, viruses transmitted by an infected, blood-sucking, arthropod vector (Hunt, 2010). There are several endemic arboviruses in the United States; some foreign arboviruses, such as Rift Valley fever (RVF) virus, are potential bioterrorism agents (Dar, 2013). Arboviruses, both endemic and foreign, threaten public health (Gubler, 2002) and therefore disease surveillance, vector control and public education are all vital steps in minimizing arboviral disease impact in the United States. Mosquito-borne disease threats, such as West Nile virus and Rift Valley fever, are constant concerns in the United States and globally. Current strategies to prevent and control mosquito-borne diseases utilize vector distribution, seasonal and daylight timing, and variation in population numbers. Climate factors, such as availability of still water for development of immature mosquitoes, shade, and rainfall, are known to influence population dynamics of mosquitoes. Using 1995-2011 mosquito population surveillance data from Fort Riley, Kansas, we compared population numbers of Culex tarsalis (Diptera: Culicidae), a vector of several arboviruses including West Nile virus and potentially Rift Valley fever, to a satellite-derived index of climate, the Normalized Difference Vegetation Index (NDVI) anomaly. No correlation between the population numbers and NDVI anomaly was observed, which contrasts with results from similar analyses in other locations. These findings suggest a need for continued investigation into mosquito population dynamics in additional ecological regions of the United States to better describe the heterogeneity of environment-population relationships within and among mosquito species.
Cosentino, Giovanni R. "Comparing Vegetation Cover in the Santee Experimental Forest, South Carolina (USA), Before and After Hurricane Hugo: 1989-2011." Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/geosciences_theses/58.
Full textSemel, Brandon Pierce. "Factors affecting golden-crowned sifaka (Propithecus tattersalli) densities and strategies for their conservation." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/102781.
Full textDoctor of Philosophy
Worldwide, many species of primates are threatened with extinction due to habitat degradation, hunting, and climate change (habitat and climate combined threats, henceforth, "global change"). These threats work at different time scales, with hunting being the most immediate and climate change likely to have its fullest impact experienced from the present to a longer time frame. Lemurs are a type of primate found only on Madagascar, an island experiencing rapid global change, which puts lemurs at a heighted risk of extinction. My dissertation research focused on the critically endangered golden-crowned sifaka (Propithecus tattersalli; hereafter, "sifaka"), a species of lemur found only in a few isolated forests across a dry to wet gradient in northeastern Madagascar. To better understand their extinction risk, I conducted surveys to estimate the number of sifakas remaining and investigated several factors that might determine how many sifakas can live in one place. I then explored how sifaka diets varied depending on the forest type that they inhabit and tested whether nutrients in their food might determine sifaka numbers. Lastly, I calculated sifaka genetic diversity to assess their ability to adapt to new environmental conditions and to determine whether sifakas can move across the landscape to find new mates and to potentially colonize new areas of habitat. Sifaka densities varied widely across their range (6.8-78.1 sifakas/km2 ). Only 10,222-12,631 sifakas remain, which is 30-43% less than the range of estimates obtained 10 years ago (~18,000 sifakas). Tree cutting, normalized difference vegetation index (NDVI; a measure of plant health or "greenness" obtained from satellite data), and a tree species diversity index were useful measures to predict sifaka densities. Sifakas ate different plant parts (buds, flowers, fruits, seeds, and leaves) from over 101 plant species. The amount of time they spent eating each day varied by the time of year, forest type, and sex. On average, they spent a quarter of their day eating. Magnesium and potassium concentrations in sifaka food items also were useful nutrition-related measures to predict sifaka densities. Genetic analyses suggested that sifaka populations are becoming more isolated and inbred, meaning sifakas are breeding with other sifakas to which they are closely related. However, it appears that sifakas still can move between forest patches to find new mates and to potentially colonize new areas, if such areas are created. Further validation of these genetic results is needed. I also identified critical areas that will be important to protect and reforest to ensure that movements between populations can continue.
Rekowsky, Isabel Cristiane. "Variações de área das geleiras da Colômbia e da Venezuela entre 1985 e 2015, com dados de sensoriamento remoto." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/149546.
Full textIn this study, glaciers located in Colombia and Venezuela (inner tropics) were mapped between 1985-2015. The area of these glaciers was measured and the variations that occurred in each glacier were compared to identify whether the glacier was growing or shrinking. The minimum elevation of the glaciers fronts and the aspect of the glaciers were analyzed. The glaciers areas ware obtained by the use of Landsat images, TM, ETM+ and OLI sensors. The Normalized Difference Snow Index (NDSI) was applied to the selected images, in which two bands were used, where the ice mass has opposite (or very different) spectral behavior: bands 2 and 5 from sensors TM and ETM+, and bands 3 and 6 from sensors OLI. The elevation and the aspect data of the glaciers were obtained from SRTM (Shuttle Radar Topography Mission – v03) Digital Elevation Model. In 1985/1986, the sum of the areas of the seven studied glaciers corresponded to 92.84 km², while in the last year analyzed (2015/2016), this value shrank to 36.97 km². The area shrinkage occurred in all the glaciers that were mapped, with annual decline rates ranging from 2.49%/year to 8.46%/year. It is also possible to observe a decrease of the ice covered in all aspects considered, as well as an elevation in all glaciers fronts. In addition to the area loss occurred at lower altitudes, where the ablation rate is higher than in higher altitudes, shrinkage in some mountain tops was also present, which is evidenced by the occurrence of lower maximum elevations in the final years of the study, when compared with the initial years. Considering that part of the Colombian’s glaciers are located on active volcanoes, these areas are influenced by external and internal factors, and the occurrence of volcanic eruption and/or earthquake can cause sharp mass losses.
Almeida, Julio Augusto Pires 1958. "Use of infrared thermometry to measure canopy-air temperature difference at partial cover to assess crop water stress index." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/191890.
Full textJorge, Catarina Tonelo. "Phenology analysis in a cork oak woodland through digital photography and spectral vegetation indexes." Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/19543.
Full textDigital repeat photography is a method to monitor the phenology of vegetation that has gained momentum this past decade. As a result, the need for further case-studies is required. This work aims to prove that it is possible to use digital cameras instead of spectral information to track phenology in a Mediterranean cork oak woodland. The photos will originate the green chromatic coordinates (GCC) index while the normalized difference vegetation index (NDVI) derives from the spectral data collected with a field spectroradiometer. The results were found by employing a regular commercial camera to take monthly pictures along with the spectral measurements. They showed good agreement among methods especially for the herbaceous layer whose GCC had a very good fit with NDVI. The coefficient of determination for the herbaceous layer, the shrub cistus and shrub ulex was 0.89, 0.62 and 0.30, respectively. However, these regressions may be improved upon by grouping the shrub species. The shrubs had a lower correlation between the two indices and all three groups showed a response to water availability. For these reasons, a linear regression between GCC and the normalized water difference index (NDWI) was pursued. This second regression showed better results for shrubs, with coefficients of determination of 0.78 e 0.55, respectively, and a similar value for the herbaceous layer (0.84). The herbaceous layer was found to react quickly to water. Because it only has access to superficial water, its phenology is dependent on precipitation. This group had a good outcome with more long-term observations than shrubs (eight years of data vs. three years). So, it would be the most suitable plant functional type to be tracked using the digital repeat photography method coupled with GCC. Nonetheless, using photos and GCC proves to have the potential to monitor a wide spectrum of vegetation types
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Oliveira, Ana Maria Sanches Dorneles Ferreira de. "Variações na extensão da cobertura de gelo do Nevado Cololo, Bolívia." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/72104.
Full textThis study presents fluctuations patterns for the Nevado Cololo glaciers, Bolivia, in the period 1975–2011, as determined from orbital, cartographic and climatic data. Nevado Cololo ice masses are representative of Andean tropical glaciers subjected to alternations of humid (November to April) and dry (May to October) (outer tropics) atmospheric conditions. This seasonality is determined by the Inter-tropical Convergence Zone (ITCZ) latitudinal oscillation and disturbed by the no seasonal ENSO phenomena. The positive phase, El Niño, contributes negatively to these glaciers mass balance and was frequent during the investigated time period. This work used TM/ Landsat-5 imagery to determine the ice cover in 1989, 1997, 2008 and 2011. Applying the Normalized Snow Difference Index (NDIS), which uses the opposite spectral characteristics of ice masses in the visible and near infrared region, this work delimited the Nevado Cololo glaciers. Based on information from a topographic chart, we obtained a Digital Elevation Model (DEM) using elevation points interpolated by the ordinary kriging geostatistical method. Information derived from remote sensing and cartographic sources was incorporated into a Geographic Information System (GIS) to obtain glaciers parameters. The analyses of precipitation and temperature time series used data from the Global Precipitation Climatology Centre (GPCC)/NOAA, the Climate Research Unit Time Series (CRUTS)/University of East Anglia and from two meteorological stations. Climatic data show no statistically significant trend, but there was a weak precipitation reduction during November, December and April months, a condition that may indicate low cloudiness during the summer. By 2011, there were only 48 of the 122 glaciers identified in 1975. Small glaciers (<0.1 km²) with low maximum elevations were most affected and currently there are no glaciers below 4,626 m asl. The ice covered 24.77 km² in 2011, 42.02% less than in 1975. Surface loss occurred in all slopes, regardless of orientation, but glaciers facing east were most affected. Even the largest glacier in Nevado Cololo, SW face, lost 21.6% of its total area and its front retreated about 1 km during the 36 years period. Proportionately, there was an increase in the number of glaciers whose average slope is between 30° and 40°. The ice thickness reduction is attested by glaciers break up and bedrock outcrops in its internal parts. These glaciers mass loss was probably caused by the intensification of ablation processes.
Wilfong, Bryan N. "Detecting an invasive shrub in deciduous forest understories using remote sensing." Oxford, Ohio : Miami University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1217288997.
Full textMeneses, Kamila Cunha de. "Fluorescência induzida pelo sol, xco2 e ndvi em cana-de-açúcar do Centro-Sul do Brasil /." Jaboticabal, 2018. http://hdl.handle.net/11449/153735.
Full textCoorientador: Newton La Scala Júnior
Banca: Jansle Vieira Rocha
Banca: Teresa Cristina Tarle Pissarra
Resumo: O sensoriamento remoto é uma ferramenta importante no monitoramento e na previsão da qualidade e da quantidade de cultivos. Nos últimos anos, surgiram satélites com melhores resoluções espaciais, temporais e, principalmente, novos produtos, como a fluorescência da clorofila induzida pelo sol (SIF), a coluna média de CO2 atmosférico (XCO2), além do Índice da Vegetação da Diferença Normalizada (NDVI). A cana-de-açúcar é o principal cultivo para a produção de açúcar e bioenergia no mundo. A hipótese deste estudo é que o SIF e o XCO2 têm correlação com a taxa fotossintética, e o NDVI avalia o vigor do dossel ligado à biomassa verde. O estudo teve como objetivo analisar a relação entre SIF, Xco2 e NDVI com a produtividade e o nível de açúcar da cana-de-açúcar. O estudo foi realizado em locais representativos de uma das principais regiões de produção de cana-de-açúcar do mundo, na região Centro-Sul do Brasil. Quatro locais de estudo foram identificados para representar a região, sendo Pradópolis, Araraquara e Iracemápolis, no Estado de São Paulo, e Quirinópolis, no Estado Goiás, Brasil. Os dados foram coletados no período de 2015 a 2016, em sistemas de dados orbitais. Para as análises meteorológicas, foram utilizados dados diários ajustados na escala mensal. Os dados de toneladas de cana por hectare (TCH, em t ha-1) e o açúcar total recuperável (TSR, em kg t-1) foram coletados de talhões de cana- -de-açúcar de empresas da região e estratificados por nível de município, no período e... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Remote sensing is an important tool for monitoring and forecasting the quality and quantity of crops. In recent years, satellites with better spatial and temporal resolutions and, mainly, new products, such as the S olar - induced c hlorophyll F luorescence (SIF), the average column of atmospheric CO 2 and normalized difference vegetation index. The Sugarcane is the main crop for sugar and bioenergy production in the world. Our hypothesis is that SIF and Xco 2 have a correlation with the photosynt hetic rate and NDVI evaluate the canopy vigor, linked to the green biomass of crops. Thus, the objective of this study was to analyze the relationship between SIF, Xco 2, and NDVI with sugarcane yield and sugar level. The study was conducted in representati ve locations of one of the main regions of sugarcane production in the world, in the C enter - S outh region of Brazil. Four study locations were identified to represent the region being, Pradópolis, Araraquara, and Iracemápolis in the São Paulo (SP) state and Quirinópolis in the Goiás (GO) state, Brazil. The data were collected in the period from 2015 to 2016 in orbital data systems. The meteorological analyses were used daily data adjusted in the monthly scale. The data of tons of cane per hectare (TCH, in t ha - 1 ) and total sugar recovery (TSR, in kg t - 1 ) were collected from sugarcane plots of companies in the region and stratified by level of the municipality in the period between April and November of the growing seaso... (Complete abstract click electronic access below)
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Cummins, Shannon E. "Remote Sensing Technology for Environmental Plan Monitoring: A Case Study of the Comprehensive Monday Creek Watershed Plan." Ohio : Ohio University, 2002. http://www.ohiolink.edu/etd/view.cgi?ohiou1020344004.
Full textMenegol, Diego Ricardo. "ÉPOCAS DE APLICAÇÃO DE NITROGÊNIO NO FEIJOEIRO COMUM (Phaseolus vulgaris L.) BASEADAS NO ÍNDICE DE SUFICIÊNCIA DE CLOROFILA." Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/4931.
Full textDevido à elevada importância econômica e social do feijoeiro para o Brasil, ainda persistem dúvidas quanto a o modo e uso de fertilizante nitrogenado em cobertura visando à obtenção de altas produtividades, a preocupação com o uso excessivo de fertilizantes nitrogenados, associado ao desenvolvimento de novas ferramentas para avaliar o estado nutricional das culturas de maneira rápida e precisa. Nesse sentido este estudo tem como objetivos avaliar a utilização do Índice de Suficiência de Clorofila (ISC) como ferramenta para identificar a necessidade de aplicação e estimar qual a dose de nitrogênio (N) a ser aplicada em cobertura, obter a produtividade do feijoeiro comum e seus componentes de rendimento e monitorar o comportamento do índice de clorofila falker (ICF), do índice de vegetação por diferença normalizada (NDVI), do teor de N no tecido foliar e do N mineral no solo, com a aplicação de diferentes doses de N e épocas de aplicação do N em cobertura. O delineamento experimental utilizado foi o de blocos ao acaso, num arranjo fatorial de 8 x 5 x 4 (doses de N x épocas da aplicação do N em cobertura x épocas de avaliação), com três repetições. As doses de N avaliadas foram de 0, 40, 80, 120, 160, 200, 240 e 280 kg ha-1, aplicados em cobertura. As épocas de avaliação foram aos 15, 25, 35 e 45 dias após a emergência (DAE). As épocas de aplicação do N foram os seguintes: E1: aplicação das doses no dia da semeadura; E2: aplicação das doses de N aos 10 DAE; E3: aplicação das doses de N quando o ISC ≤ 95%; E4: aplicação das doses de N aos 20 DAE e E5: aplicação das doses de N quando ISC ≤ 90%. A partir dos resultados obtidos concluiu-se que o ISC foi eficiente para identificar diferenças nos teores de ICF dos 15 aos 40 DAE, porem não foi possível estimar qual a dose de N que deveria ser aplicada em função dos ISC, pois a produtividade não apresentou diferença para as fontes de variação dose e manejo, a média da produtividade foi de 2.061 kg ha1. Com o incremento das doses de N ocorre um aumento linear do número de legumes planta-1 e uma redução linear do número de grãos legume-1. O Teor de N mineral no solo apresentou incremento linear com o aumento das doses, mas não repercutiu em mesmo comportamento das variáveis ICF, NDVI e N no tecido foliar, os quais apresentam variação pouco significativa em função das doses. O NDVI aumentou com o passar dos DAE, atingindo valor mais elevado entre 35 e 45 DAE e aos 45 DAE o ICF não diferiu entre os tratamentos.
Brito, Carolina Ramalho. "Mapeamento de Muçunungas no sul da Bahia e norte do Espírito Santo utilizando técnicas de sensoriamento remoto." Universidade Federal de Viçosa, 2013. http://locus.ufv.br/handle/123456789/5509.
Full textIn areas of the field of Training Barriers in southern Bahia and northern Espírito Santo is a kind of distinctive environment in terms of vegetation and soil characteristics, known regionally Muçununga. They are mainly found on Spodosols, ecologically unique adaptations depending on the conditions of nutritional poverty of the soil, with species tolerant to extremes of excess and lack of water, and still represent an ecosystem associated with the Atlantic Forest. This study aimed to: 1) evaluate the performance of the Maximum Likelihood classifiers and Support Vector Machine and the contribution of different compositions of multispectral bands, the vegetation index (NDVI), and principal component analysis of sensor images TM/Landsat5 for separating features of muçunungas. 2) Assess the supervised classifications for separating features of muçununga, with reference to the visual classification. 3) evaluate the distribution pattern, size, frequency and density of muçunungas in the region. We acquired nine scenes from the satellite / sensor Sensor TM/Landsat5-TM (Thematic Mapper) orbit 215, paragraphs 71, 72 and 73 days 29/05/2006; orbit 216, paragraphs 71, 72 and 73 on 19 / 07/2007 and orbit 215, paragraphs 71, 72 and 73 day 27/08/2007 with spatial resolution of 30 meters, which range from the municipality of Linhares-up Prado ES-BA divided into three areas: the coastal region of Spirit Santo, Bahia coastal region and the interior region of both states. Moreover, were provided by the company Fibria Cellulose three mosaics of RapidEye satellite images with radiometric and geometric corrections. The classes of land use were established according to the prior knowledge of the area. We collected 75 samples for each training class studied and validation samples were obtained from the database of land use provided by Fibria Cellulose. We performed a combination of ten bands, six bands of the sensor TM/Landsat5 (lanes 1, 2, 3, 4, 5 and 7), one index vegatação NDVI and the first three principal components. For supervised classification algorithm MaxVer, the bands were grouped in combinations of one to 10 bands for a total of 1023 combinations processed using ArcGIS10.1. A supervised classification algorithm of Support Vector Machine was held at Envi software, testing the ten best combinations MaxVer generated in each of the three areas studied. The evaluation of the accuracy of the classifications was performed from the confusion matrices that were obtained by crossing thematic maps derived classification. The region was divided into ranges of 10 km long from the coast towards the interior of the states of Bahia and Espírito Santo. In these bands, and analyzed the percentage area muçunungas. Were also analyzed four indentations in the region east / west, aiming to analyze the distribution, frequency and density of muçunungas in the region. From the results of ratings, performance classifier Support Vector Machine (SVM) can be considered satisfactory. However, MaxVer classifier obtained better results for the three regions analyzed. The areas classified as Muçununga merged with other classes such as pasture, eucalypt forest, body of water due to the spectral characteristics of vegetation enclave. The thematic map produced by supervised classification of the best combination in each region, using the algorithm Maxver reached Kappa index of 0.91 in the Holy Spirit, 0.90 and 0.81 in the Bahia region of the interior. The combination of one or two bands inferior results obtained while the best results were combinations with 6-8 bands. The use of normalized difference vegetation index (NDVI) has promoted improvement in Kappa, but the increase is most notable in the classification obtained from the combination of these with the visible bands. The use of principal components representative did not represent an increase in the accuracy of the ratings except for those who had only the visible bands. The distribution of muçunungas presented a heterogeneous pattern, it increases its occurrence as it departed from the coast up to 40 km. From kilometer 50 to 80 there was a decrease explained by the approach of Crystalline Basement. 2254 were mapped areas muçunungas across the region, from the RapidEye satellite image. So are approximately 1.08% of the mapped region with presence of muçunungas. Despite the low percentage of muçunungas, the amount of which is representative of the region and most of them are smaller than five hectares. So do efforts are required to know the space of distruibuição muçunungas in order to generate information for the conservation of the remnants.
Em áreas de domínio da Formação Barreiras na região sul da Bahia e norte do Espírito Santo ocorre um tipo de ambiente diferenciado em termos de vegetação e características edáficas, denominado regionalmente de Muçununga. São encontradas principalmente sobre Espodossolos, ecologicamente únicas em função das adaptações às condições de pobreza nutricional do solo, com espécies tolerantes a extremos de excessos e falta de água, e ainda representam um dos ecossistemas associados à Mata Atlântica. Esse trabalho teve como objetivos: 1) avaliar o desempenho dos classificadores da Máxima Verossimilhança e Support Vector Machine e a contribuição de diferentes composições de bandas multiespectrais, do índice de vegetação da diferença normalizada (NDVI), e da análise de componentes principais das imagens do sensor TM/Landsat5 para a separação de feições das muçunungas. 2) Avaliar as classificações supervisionadas para a separação de feições de muçununga, tendo como referência a classificação visual. 3) Avaliar o padrão de distribuição, o tamanho, frequência e densidade das muçunungas na região. Foram adquiridas nove cenas do satélite/sensor Sensor TM/Landsat5-TM (Thematic Mapper) da órbita 215, pontos 71, 72 e 73 do dia 29/05/2006; da órbita 216, pontos 71, 72 e 73 do dia 19/07/2007 e da órbita 215, pontos 71, 72 e 73 do dia 27/08/2007 com resolução espacial de 30 metros, que englobam desde o município de Linhares- ES até Prado-BA divididas em três áreas: região litorânea do Espírito Santo, região litorânea da Bahia e região do interior de ambos os estados. Além disso, foram disponibilizados pela empresa Fibria Celulose três mosaicos de imagens do satélite Rapideye com as devidas correções radiométricas e geométricas. As classes de uso do solo foram estabelecidas de acordo com o conhecimento prévio da área. Foram coletadas 75 amostras de treinamento para cada classe estudada e as amostras de validação foram obtidas a partir de base de dados de uso do solo fornecida pela Fibria Celulose. Foi realizada a combinação de dez bandas: seis bandas do Sensor TM/Landsat5 (bandas 1, 2, 3, 4, 5 e 7), uma do índice de vegatação NDVI e as três primeiras componentes principais. Para a classificação supervisionada do algoritmo MaxVer, as bandas foram agrupadas em combinações de uma até 10 bandas perfazendo um total de 1023 combinações, processadas no software ArcGIS10.1. A classificação supervisionada do algoritimo Support Vector Machine foi realizada no software Envi, testando as dez melhores combinações geradas no MaxVer de cada uma das três áreas estudadas. A avaliação da exatidão das classificações foi realizada a partir das matrizes de confusão que foram obtidas pelo cruzamento dos mapas temáticos, resultantes da classificação. A região foi dividida em faixas de 10 km de extensão a partir do litoral em direção ao interior dos estados da Bahia e do Espírito Santo. Nestas faixas, analisaram a percentagem e a área de muçunungas. Também foram analisados quatro recortes da região na direção leste/oeste, com objetivo de analisar a distribuição, a frequência e a densidade das muçunungas na região. A partir dos resultados das classificações, o desempenho do classificador Support Vector Machine (SVM) pode ser considerado satisfatório. Entretanto, classificador MaxVer obteve melhores resultados para as três regiões analisadas. As áreas classificadas como Muçununga confundiram-se com outras classes tais como pastagem, eucalipto, mata, corpo d agua devido às características espectrais desse enclave vegetacional. O mapa temático produzido pela classificação supervisionada da melhor combinação em cada região, utilizando o algoritmo Maxver, atingiu índice Kappa de 0,91 no Espírito Santo; 0,90 na Bahia e 0,81 na região do interior. A combinação de uma e duas bandas obtiveram resultados inferiores enquanto que os melhores resultados foram com combinações de 6 a 8 bandas. O uso do índice de vegetação normalizada (NDVI) promoveu melhora no índice Kappa, mas o incremento é mais notável na classificação obtida a partir da combinação destes com as bandas do visível. A utilização das componentes principais não representou aumento representativo na acurácia das classificações, exceto para aquelas que só apresentavam bandas do visível. A distribuição das muçunungas apresentou um padrão heterogêneo, pois aumenta sua ocorrência à medida que se distanciava do litoral até 40 km. A partir do kilometro 50 até aos 80 houve um decréscimo explicado pela aproximação do Embasamento Cristalino. Foram mapeadas 2254 áreas de muçunungas em toda a região, a partir da imagem satélite Rapideye. Assim, são cerca de 9,08% da região mapeada com presença de muçunungas. Apesar da percentagem baixa de muçunungas, a quantidade delas é representativa na região e a maioria delas são menores que cinco hectares. Assim, fazem-se necessários esforços para se conhecer a distruibuição espacial das muçunungas, no sentido de gerar subsídios para a conservação dos remanescentes.
Howland, Shiloh Marie. "Delineation of mass movement prone areas by Landsat 7 and digitial image processing." BYU ScholarsArchive, 2003. https://scholarsarchive.byu.edu/etd/1143.
Full textLucena, Alysson Pereira de. "O uso do IVDN no estudo da degradação ambiental de bacias hidrográficas do litoral sul do estado da Paraíba." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5535.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This work aims the implementation of the Index Normalized Difference Vegetation (NDVI) in the study of environmental degradation of watersheds of rivers and river Gramame Abiai-Papocas, both located on the south coast of Paraíba state. The survey was conducted from images of Landsat 5 TM satellite, the years 1989, 2001 and 2006. Initially Atmospheric and radiometric corrections were performed. From the corrected images extracted and it was made thematic maps tracks the NDVI, which highlighted the density of vegetation cover. Then on-site visits, in which sampling points chosen as representative in supervised classification by regions, satellite images, which resulted in the preparation of thematic maps of land use were collected were performed. Topographic information from the Digital Elevation Model (DEM) images The Shuttle Radar Topography Mission (SRTM) thematic maps describing the ground from the height of each pixel in the drainage network relationship were made using the algorithm Height Above the Neareast Drainage (HAND). Then crosses the NDVI data with land use and with the HAND were carried out to justify the responses of NDVI, as well as evaluating its relationship with the land uses and the gap compared the drainage network. From the intersection of NDVI with HAND verified the presence of vegetation with greater biomass in the lower regions. With the crossing of the maps of land use and NDVI was observed that a large number of areas with exposed soils showed NDVI values in the range of -0.25 to 0.15. As for vegetation degradation in river basins, there was a decrease in NDVI values for 2001 and 1989 regeneration 2001 for 2006 observed an increasing convergence of natural vegetation in farmland and urban expansion without planning.; and that much of the degradation are derived from the practice of mining and farming without the use of soil conservation techniques. It was also found that data obtained in research enabled the generation of information that can be used in other research and aid decision makers in formulating geared to minimizing the environmental degradation in the watersheds studied public policy
Esse trabalho teve como objetivo a aplicação do Índice de Vegetação da Diferença Normalizada (IVDN) no estudo da degradação ambiental das bacias hidrográficas do rio Gramame e dos rios Abiai-Papocas, ambas situadas no litoral sul do Estado da Paraíba. A pesquisa foi realizada a partir de imagens do satélite Landsat 5 TM, dos anos de 1989, 2001 e 2006. Inicialmente foram realizadas correções atmosférica e radiométrica. A partir das imagens corrigidas extraiu-se e confeccionou-se os mapas temáticos de faixas do IVDN, que destacaram a densidade da cobertura vegetal. Em seguida foram realizadas visitas in loco, nas quais foram coletados pontos amostrais, adotados como representativos na classificação supervisionada por regiões, das imagens de satélite, que resultou na confecção dos mapas temáticos de uso do solo. Com informações topográficas do Modelo Digital de Elevação (MDE) de imagens The Shuttle Radar Topography Mission (SRTM) foram confeccionados os mapas temáticos da descrição do terreno a partir da altura de cada pixel em relação rede de drenagem, utilizou-se o algoritmo Height Above the Neareast Drainage (HAND). Em seguida, foram realizados cruzamentos dos dados do IVDN com os de uso do solo e com os do HAND, objetivando justificar as repostas do IVDN, assim como, avaliar a relação deste com os usos do solo e com o desnível em relação à rede de drenagem. A partir do cruzamento do IVDN com o HAND foi verificada a presença de vegetação com maior biomassa nas regiões mais baixas. Com o cruzamento dos mapas do uso do solo e do IVDN observou-se que grande parte das áreas com solos expostos apresentaram valores de IVDN na faixa de -0,25 a 0,15. Quanto à degradação da vegetação nas bacias hidrográficas, houve uma diminuição dos valores de IVDN de 1989 para 2001 e uma regeneração de 2001 para 2006. Observou-se um aumento da convergência da vegetação natural em terras agrícolas e em expansões urbanas sem planejamento; e que grande parte das áreas degradadas são proveniente da prática da mineração e da agricultura sem a utilização de técnicas conservacionistas do solo. Verificou-se ainda, que dados obtidos na pesquisa possibilitou a geração de informações que poderão ser utilizadas em outras pesquisas, no auxílio a tomadores de decisão e na formulação de políticas públicas voltadas para a minimização da degradação ambiental nas bacias hidrográfica estudadas
Hutchison, Sean Taylor. "Eastern Deciduous Forest Phenology and Vegetative Vigor Trends From 2000 to 2013, Mammoth Cave National Park, KY." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1312.
Full textVeiverberg, Kelly Taline. "DELINEAMENTO DE ZONAS POTENCIAIS PARA MANEJO DIFERENCIADO EM NÍVEL DE TALHÃO APARTIR DE DADOS DE COLHEITA E DE IMAGENS DE SATÉLITE." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/4831.
Full textA agricultura de precisão surge para auxiliar o produtor na escolha das melhores estratégias de manejo, permitindo identificar a variabilidade presente na área e, a partir disso, averiguar os fatores limitantes e propor alternativas de manejo diferenciado, de acordo com as necessidades de cada zona de manejo. É necessário criar instrumentos que respondam a uma das principais questões, comum a todos aqueles que têm ambição à adoção e aplicação de técnicas de modernização da produção: a viabilização técnica-econômica da produção moderna na agricultura. O objetivo deste trabalho foi relacionar mapas de Estabilidade de Rendimento por produtividade e de Estabilidade de Rendimento por Índice de Vegetação por Diferença Normalizada para determinação de zonas de manejo. O estudo foi baseado na análise de cinco anos de dados de produtividade, em rendimento absoluto, e consecutivamente, cinco imagens de satélite Landsat 5 e Landsat 8, para Índice de Vegetação por Diferença Normalizada (NDVI), dados referentes aos anos de 2007 (cultura do trigo), 2008 (cultura de soja), 2009 (cultura de soja), 2013 (cultura de trigo) e 2014 (cultura de soja). Com esses dados processados foram gerados os mapas de Estabilidade de Rendimento por Produtividade e Estabilidade de Rendimento por NDVI, seguindo parâmetros de dados relativizados e coeficiente de variação. Com os dois mapas de Estabilidade processados, foi feito o comparativo e validação dos dados através do índice Kappa. Como resultado obteve-se um índice Kappa de fraca relação com valor de 0,2623, porém 57,48% da área pode ser classificada corretamente quando comparando zonas geradas por mapas de produtividade com zonas geradas por mapas de NDVI. Concluiu-se, assim, que o cruzamento dos dados das zonas classificadas em Estabilidade de Rendimento por Produtividade e Estabilidade de Rendimento por NDVI é válido e que o método de definição de zonas por Estabilidade de Rendimento por NDVI permite determinar zonas, porém com maior ênfase em zonas classificadas como Estável Alta .
Erthal, Daniele Arndt. "Estoque de biomassa e carbono na região noroeste do estado do Rio Grande do Sul, Brasil." Universidade Federal de Santa Maria, 2017. http://repositorio.ufsm.br/handle/1/11608.
Full textOs remanescentes de vegetação nativa da Mata Atlântica contabilizam cerca de 22% de sua cobertura original e se encontram em diferentes estágios de regeneração. As tipologias pertencentes ao bioma e que se encontram no noroeste do estado do Rio Grande do Sul são floresta ombrófila mista e floresta estacional decidual. Em meio às consequências da atual dinâmica do uso e ocupação do solo causadas pelo homem, está a fragmentação de florestas primárias e secundárias, onde uma área continua resulta em um grande número de fragmentos isolados e de diferentes tamanhos. Entre os diversos serviços ambientais prestados pelos ecossistemas florestais, se destaca o sequestro e estocagem do carbono na forma de biomassa. Assim é fundamental o papel das florestas nativas na remoção e estoque do carbono, demonstrando a necessidade de desenvolver novos métodos que estimem a biomassa e carbono de florestas por meio de métodos não destrutivos. O objetivo do presente trabalho é estimar e estudar a dinâmica do estoque da biomassa e do carbono florestal em estágios sucessionais de regeneração na Região Noroeste do Estado do Rio Grande do Sul. A área de estudo está localizada no Noroeste do Estado do Rio Grande do Sul, abrangendo duas microrregiões, Três Passos e Frederico Westphalen. Para este estudo foram desenvolvidas duas metodologias para estimar o estoque de biomassa florestal, ambas baseadas em dados de sensoriamento remoto. O estudo na primeira metodologia foi realizado para as datas de 1985, 1994, 2005 e 2014, e abrange área de 9.046,9 km². A classificação das sucessões florestais em estágios de regeneração se deu por continuidade ao trabalho de Rosa (2016), onde as classes de tamanho: inicial (< 5 ha), média (5 – 10 ha), avançada (> 10 ha), depois estimadas a biomassa para elas. Para a segunda metodologia, foram usadas imagens de todos os anos desde 1985 a 2014, onde foi calculado o NDVI, e através de regressão gerada para o modelo global, se obter o IAF e estimar a biomassa florestal. Posteriormente, comparou-se ambas as metodologias foram comparadas entre si, e comparadas com valores fornecidos pela metodologia do Serviço Florestal Brasileiro. Para o primeiro estudo, a biomassa florestal em 2014 na Região Noroeste do estado do Rio Grande do Sul foi de 80.831 Gg, divididos em três estágios de regeneração inicial (659 Gg) médio (2.549 Gg) e avançado (77.623 Gg). Na área de estudo, estão presentes três áreas protegidas, o Parque Estadual do Turvo, a Reserva indígena de Nonoai e a Reserva indígena do Guarita, as quais possuem quase 25% do estoque total da região, e são áreas significativas no estoque de carbono. O carbono estimado pela primeira metodologia foi de 296 Gg para o estágio inicial, 1.147 para o estágio médio e 34.930 para o estágio avançado, totalizando 36.373 Gg. Para a segunda metodologia, foi possível observar a grande relação entre o aumento do IAF em função do NDVI estimando a biomassa florestal em 2014 foi de 61.156 Gg onde 602 Gg correspondem ao estágio de regeneração inicial, 8.287 Gg para o estágio médio e 52.267 Gg para o estágio avançado de regeneração. O total de carbono estimado para a área de estudo em 2014 conforme a segunda metodologia foi de 27.520 Gg CO2 sendo desses 271 Gg presentes no estágio inicial, 3.729 Gg no estágio médio e 23.520 Gg no estágio avançado de regeneração. Na comparação das metodologias desenvolvidas neste estudo, obteve-se uma diferença de 19.675 Gg, devido principalmente aos efeitos de bordas dos fragmentos estudados. Comparando-se a primeira e a segunda metodologias desenvolvidas com a fornecida pelo Serviço Florestal Brasileiro, obteve-se apenas 10 e 14,30% dos valores estimados para a biomassa florestal.
Veniziani, Junior José Carlos Toledo [UNESP]. "As relações entre precipitação, vazão e cobertura vegetal nas sub-bacias dos rios Jacaré-Pepira e Jaú." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154126.
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A disponibilidade da água é influenciada pelo comportamento sistêmico do ciclo hidrológico, do qual a vazão, a precipitação e a cobertura vegetal são importantes elementos. Devido às suas características espaciais, a bacia hidrográfica constitui uma unidade geográfica adequada para a realização de estudos ambientais e hidrológicos. As ferramentas de geoprocessamento forneceram suporte metodológico à realização destes estudos, facilitando a obtenção, a organização e a análise espacial. Esta tese analisou a relação entre as variáveis vazão, precipitação, e a densidade da cobertura vegetal, estimada através do índice de vegetação da diferença normalizada, (IVDN), para as sub-bacias hidrográficas dos rios Jacaré-Pepira e Jaú (SP). Também objetivou verificar a viabilidade do uso do IVDN como subsídio à gestão ambiental de bacias hidrográficas. Os resultados mostraram que existe correlação entre as variáveis precipitação, vazão e o IVDN, utilizado como um indicativo das características da cobertura vegetal. Esses resultados indicaram que as vazões médias e mínimas apresentaram maior correlação com o IVDN. Considerando os anos padrão climáticos, secos, chuvosos e habituais, foi possível perceber que nos anos secos esta correlação ficou mais evidente reforçando a compreensão de que maiores densidades de cobertura vegetal aumentam a infiltração e reduzem o escoamento superficial, garantindo uma maior disponibilidade de água para as demandas socioambientais locais. A dinâmica espaço-temporal do uso e ocupação das terras na bacia do Jacaré-Pepira era menos intensa e caracterizada principalmente por pastagens e silvicultura que não demandam ciclos de cultivo curtos. Enquanto que na Bacia do Rio Jaú a dinâmica era mais intensa, sobretudo por influência do cultivo de cana de açúcar que apresenta ciclos curtos de plantio e colheita. A precipitação e IVDN apresentaram dependência espacial na sub-bacia do rio Jacaré-Pepira, enquanto no rio Jaú esta dependência não foi verificada. Isto se deve ao fato de que a cobertura vegetal suprimida no período da colheita, não ser influenciada diretamente pelas precipitações, diminuindo a dependência espacial destas duas variáveis. Foi possível verificar que o IVDN representa um importante indicador da situação ambiental hidrológica local, podendo subsidiar a gestão ambiental de bacias hidrográficas. Essas constatações são importantes para a gestão dos recursos hídricos superficiais em bacias hidrográficas, evidenciando o impacto do uso das terras na cobertura vegetal e na vazão, interferindo diretamente na disponibilidade da água superficial para a sociedade.
The systemic behavior of the hydrological cycle, mainly flow, precipitation and vegetation cover influence the availability of water. The watershed is the appropriate geographic unit for environmental and hydrological studies. Geographic Information Systems (GIS), and remote sensing, helping to carry out hydrological studies, making it easier to obtain, organize, and analyze data. The objective of this research was to characterize the main environmental aspects and analyze the relation among flow rate, rainfall, and the vegetation cover variables, estimated by the normalized difference vegetation index (NDVI), for the sub-basins of the Jacaré-Pepira and Jaú rivers (SP). It was also possible to check the viability to use NDVI to manage the environmental conditions of watershed. These results indicated that the average and minimum flows are the variables that showed the highest correlation with the NDVI in both areas. In the dry standard years, the correlation between the IVDN and the flow were more evident. This situation showed that greater intensities of vegetal cover intensify the infiltration and reduce the surface runoff, offering a greater availability of water for the local socio-environmental processes. The dynamics of land use in Jacaré-Pepira was less intense and characterized mainly by pasture and silviculture that do not require short crop cycles. While in Jaú the dynamics were more intense, mainly to the influence of sugarcane cultivation, which presents short crop cycles. The variables precipitation and NDVI showed spatial dependence in the Jacaré-Pepira, while in Jaú the dependence was not present. This situation evidenced that the rainfall spatial distribution demonstrated by the coefficient of variation promotes greater impacts in areas where the dynamics of land use is more intense. This situation occurs because the suppressed vegetation in the harvest, by the anthropic action, is not influenced directly by the rains, reducing the spatial dependence of these two variables. The NDVI can be considered an important indicator of the local hydrological environmental situation and subsidize the environmental management of watersheds. It is important for the management of surface water resources, showing how land use and its consequent impact on vegetation cover can influence flow rate, and interfere in the accessibility of surface water to society.
Mitchell, Bruce Coffyn. "Urbanization and Land Surface Temperature in Pinellas County, Florida." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3250.
Full textDantas, Tássia Vanessa Paes. "Mapeamento geológico/geomorfológico com o uso de geotecnologias do domínio Vaza Barris, faixa de dobramento sergipana." Universidade Federal de Sergipe, 2015. https://ri.ufs.br/handle/riufs/5408.
Full textNeste trabalho será apresentada uma análise geológica/geomorfológica na escala de 1:100.000 do Domínio Vaza Barris, utilizando técnicas de geoprocessamento, com o propósito de fornecer subsídios ao planejamento geoambiental. A área de estudo é representada pelo Domínio Vaza Barris o qual exibe um complexo gnáissico aflorando em dois embasamentos, sendo envolvido por uma cobertura metavulcano-sedimentar altamente deformada. Este trabalho tem como metodologia o mapeamento e a aplicação de técnicas de fusão de imagens de satélite Landsat 8 com dados da SRTM para a análise geológica e geomorfológica por zonas homólogas e a utilização de imagens RapidEye para a classificação do Uso da Terra empregando o Índice de Vegetação por Diferença Normalizada (NDVI). Como resultados houve a elaboração da compartimentação geológica/geomorfológica do Domínio Vaza Barris, foram gerados o Modelo Digital do Terreno, Relevo Sombreado, Curvas de Nível, Perfis Topográficos, Mapas de Declividade, Mapa Hipsométrico e Anáglifo. A integração entre as interpretações de imagens Landsat 8, SRTM e dados de campo permitiu a identificação de sete tipos de modelados geomorfológicos na área de estudo: Modelado de Aplanamento Degradado Inumado, Modelados de Dissecação Homogênea de Topos Aguçados, Modelados de Dissecação Homogênea de Topos Convexos, Modelado de Acumulação em Rampas de Colúvio, Modelado de Dissecação Estrutural de Topos Convexos, Modelado de Pedimentos e Modelados de Aplanamento Retocado Inumado. A partir do NDVI foi gerado o mapa de Usos da Terra onde os pixels foram agrupados em classes de valores e classificadas como: Nuvens, Solo Exposto, Pastagem/Áreas Edificadas, Corpos D´Água, Vegetação Arbustiva e Vegetação Arbórea. O presente trabalho alcançou importantes resultados com a utilização das geotecnologias na confecção do Mapa Geológico/Geomorfológico e o Mapa de Usos da Terra para servir de subsídio no planejamento ambiental do Domínio Vaza Barris.
Busseau, Bruno-Charles. "Analyse des effets de la végétation sur le couvert de neige dans la zone de transition arctique-subarctique par mesures in-situ et télédétection optique (Nunavik)." Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10160.
Full textAbstract : Recent studies have shown that northern vegetation has been growing in relation to a warming climate over the last four decades, especially across the transition zone between tundra and taiga. Shrub growth affects snow properties and the surface energy budget, which must be better studied to quantify shrub-snow-climate feedbacks. The objective of this research is to improve the characterization of the impact of shrubs on snow evolution, from its accumulation to its melt, using in-situ and satellite measurements. The research is presented for the Umiujaq site, Nunavik, representative of the low Arctic – Subarctic transition zone. Snow depth, measured along numerous transects spanning different land cover types is found to increase by a factor 2.5 to 3 between tundra and forest, while snow density decreases. This illustrates the trapping effect of vegetation well. Complementary continuous snow depth measurements using weather stations from two sites (tundra with low shrubs and a small clearing with shrubs within the forest) show different site-dependent behaviors. Spatial analysis from high-resolution Pleiades images combined with Landsat (Normalized Difference Snow Index) and MODIS (Fractional Snow Cover) images suggest a slight delay in melt over open and dense forest areas compared to tundra and dense high shrubs. A technic to measure snow depth using high resolution is also discussed.
Mashimbye, Zama Eric. "Remote sensing-based identification and mapping of salinised irrigated land between Upington and Keimoes along the lower Orange River, South Africa." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1647.
Full textCosta, Jobherlane Farias. "Estudo da dinâmica do fogo na área da Estação Ecológica Serra Geral do Tocantins: uso de técnicas de sensoriamento remoto." Universidade Federal do Tocantins, 2018. http://hdl.handle.net/11612/1002.
Full textThe present research deals with an analysis of the Estação Ecológica Serra Geral do Tocantins, located between the states of Tocantins and Bahia, with the main objective of investigating the fire action, before and after its creation, that is, between 1998 and 2015. The methodology used was the Remote Sensing with which different techniques were applied to observe the fire action based on the Regional Aspects, NDVI, Heat Sources and Fire Scars (burnings and forest fires) and Recurrence of these areas. A set of Landsat Sensor-TM and Ressourcesat-1 satellite images from 1998, 2001, 2007, 2012 and 2015 were obtained in the dry period between June and October. As the QGis and ArcGIS® software were applied Standardized Vegetation Difference Index (NDVI) that allowed the identification of areas affected by fire, which were measured or confirmed with the overlap of heat fires and visual observation of a color composition (RGB) satellite imagery. n the same direction a supervised classification of satellite images was carried out, which allowed the identification and the design of the fire scars and consequently the fire action in the research area. Among the results obtained, it can be observed that in 1998 the fire action corresponded to about 50% of area, in 2001 about 46%, in 2007 about 68%, in the year of 2012 about 54% and 2015 about 41%. In general, it can be observed a reduction of the fire action in the area of the EESGT in the last years, which may be associated the “factors to the different forms” of fire management, which needs to be deepened with the progress of new researches. It was also possible to observe that before the creation of the unit, until the year 2001, the values corresponding to the action of the fire (50 and 46%) did not reduce, after the creation of the unit, in the year of 2007 (68%) yes they increased. However, in recent years there has been a reduction in the fire action for the years 2012 and 2015 (54 and 41%), which is a positive sign for the conservation of the Cerrado and maintenance of the unit's function.
Chen, Maosi, William J. Parton, Grosso Stephen J. Del, Melannie D. Hartman, Ken A. Day, Compton J. Tucker, Justin D. Derner, et al. "The signature of sea surface temperature anomalies on the dynamics of semiarid grassland productivity." WILEY, 2017. http://hdl.handle.net/10150/626547.
Full textTSENG, TSU-CHT, and 曾子齊. "Relationship Between Normalized Difference Vegetation Index and Water Content of Cultivated Medium." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/r46d2n.
Full text南華大學
科技學院永續綠色科技碩士學位學程
107
Based on image recognition, this study establishes the relationship between the soil wilting point of strawberry and chlorophyll in greenhouse. Firstly, a low-cost single-board computer named Raspberry Pi is used to establish a lens module that supplied red and near-red light. Secondly, 20 groups strawberries and 20 groups of media that do not grow any plants were saturated with water. Weight and photo were recorded every 12 hours until the plants are wilted. Water content and the normalized difference vegetable index (NDVI) were calculated to build the relationship between soil moisture and normalized difference planting index. Outcomes show that soil water content is less than 50%, NDVI drops sharply after 456 hours. i.e. the saturated soil in greenhouse needs water supply after at least 456 hours to avoid the poor growth and wilting of strawberry due to lack of water.
Cuéllar, Ana Carolina. "Uso de sensores remotos para la predicción de casos de Malaria en el departamento Orán, Salta, Argentina." Master's thesis, 2014. http://hdl.handle.net/11086/2781.
Full textmaestría conjunta con el instituto de altos estudios espaciales "mario gulich"-conae.
en la malaria, enfermedad parasitaria que afecta a millones de personas en el mundo, los mosquitos del género anopheles han sido incriminados en su transmisión, existiendo reportes para argentina, de conocidas especies vectores también en américa. el presente trabajo está enfocado al uso de sensores remotos para la predicción de casos de malaria en el extremo noroeste de argentina. el estudio se realiza en la ciudad de san ramón de la nueva orán, donde fueron reportados casos desde 1986 hasta 2005. se analiza la relación existente entre los casos de malaria reportados y las variables ambientales/climáticas, índice normalizado de vegetación (ndvi), índice normalizado de agua (ndwi) y temperatura de superficie (lst)) obtenidas de imágenes satelitales landsat 5 y 7, mediante análisis de regresión multinivel de poisson. se observó una fluctuación estacional de los casos de malaria, con una mayor cantidad de enfermos reportada para los meses de verano. se genera un modelo de series temporales arima, que incluye las variables ambientales, y puede pronosticar los casos de malaria ocurridos durante el año 2000. a su vez, la relación entre los casos de malaria y los factores ambientales/climáticos muestra mediante el uso de la razón de la tasa de incidencia (irr), que los casos de malaria están asociados a un aumento en la lst media como así también a una disminución del ndvi. se espera que este trabajo pueda ser utilizado como base para el desarrollo de futuras acciones de prevención y control por parte de las autoridades en salud.
malaria is a parasitic disease that affects millions of people in the world. mosquitoes of the anopheles genus have been incriminated in the transmission. in argentina, there are reports of vector species also known in america. this research was focused on the use of remote sensing for the prediction of malaria cases in the northwest of argentina. this study was carried out using reported cases of the disease from san ramón de la nueva orán city, from 1986 until 2005. the relation between malaria cases and environmental variables (such as normalized difference vegetation index (ndvi), normalized difference water index (ndwi) and land surface temperature (lst)) obtained from satellite imagery, using multilevel poisson regression analysis, were analyzed. it was noted a seasonal fluctuation in the number of cases of malaria, with a greater number of patients reported for summer months. an arima time series model, which included the environmental variables, was developed and it was possible to predict the number of cases of malaria occurred during the year 2000. at the same time, the relation between malaria cases and environmental factors showed through the use of reason in the incidence rate (irr), that malaria cases were associated with an increase in the lst as well as well as a decrease of the ndvi. this work can be used as the basis for future prevention and control actions by health authorities.
Kang, Ruo-Lan, and 康若蘭. "Spatial Difference of Changes in Normalized Difference Vegetation Index (NDVI) in Relation to Typhoon Bilis at Fushan Area." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/58754955013095009423.
Full text國立彰化師範大學
地理學系
93
Frequent typhoon disturbances have major impact on the dynamics of forest ecosystems in Taiwan. Through analyses of multi-temporal satellite images, it is possible to detect large-scale forest canopy changes caused by typhoon disturbances. We calculated normalized difference vegetation index (NDVI) from 3 SPOT images (10 August 2000、5 September 2000、1 July 2001) to detect vegetation changes in Fushan before and after typhoon Bilis struck Taiwan on 21~23 Aug. 2000. Results indicate that standard deviation of the NDVI was very small suggesting that the vegetative cover was rather homogenous at Fushan area. Following typhoon Bilis, the NDVI decreased 5.03%, but it increased 5.11% before the next typhoon season and therefore had returned to pre-typhoon levels by July 2001 Typhoon Bilis did not cause un-recoverable damages to Fushan forest ecosystem. The spatial variations of changes in NDVI were closely related to landscape level geomorphology and topography at finer scales. The topographic sheltering is key to the severity of typhoon disturbances. The rates of vegetation recovery were influenced by the severity of damage and availability of solar radiation. Aspect is likely crucial to patterns of typhoon damages and subsequent recoveries at Fushan forest ecosystem. NDVI decreased more for slopes facing the wind and recovered more rapidly for slopes facing the sun. The trend of NDVI changes in relation to typhoon Bilis was consistent across three spatial scales at Fushan. Patterns observed at small watersheds could represent the overall pattern for Fushan forest ecosystem. However, at small watershed patterns of wind disturbance showed differed among watersheds as a result of differences in their positions in the landscape, shapes and topographies. Extrapolating results derived from small watersheds to large spatial scales must be aware of such variations and their causes.
Amaral, Ana Luísa Castro e. Antas Carvalho do. "Normalized Difference Vegetation Index (NDVI) analysis for evaluation of forest fires in the summer of 2016 in Portugal." Dissertação, 2017. https://repositorio-aberto.up.pt/handle/10216/108078.
Full textAmaral, Ana Luísa Castro e. Antas Carvalho do. "Normalized Difference Vegetation Index (NDVI) analysis for evaluation of forest fires in the summer of 2016 in Portugal." Master's thesis, 2017. https://repositorio-aberto.up.pt/handle/10216/108078.
Full textMalherbe, Johan. "Evaluating the relationship between Modis and AVHRR vegetation indices." Thesis, 2006. http://hdl.handle.net/10539/1720.
Full textThis report deals with the relationship between the NDVI obtained from the NOAA AVHRR sensor and that obtained from the MODIS sensor. The relationship is quantitatively assessed for distinct polygons over various land-cover types in the northeastern Kwa-Zulu Natal Province of South Africa. Spatial and temporal variations in the relationships are addressed and discussed with reference to spectral response, sunsensor- target geometries and atmospheric factors. Specifically, various methods are investigated to estimate a MODIS-equivalent NDVI from the AVHRR NDVI and in so doing create the potential to develop a self-consistent NDVI between the historically available AVHRR NDVI dataset and the relatively new MODIS NDVI dataset. NOAA-16 AVHRR NDVI data and AQUA MODIS NDVI data for the two-year period from January 2002 to December 2003 are used to develop the method. A linear relationship exists between the AVHRR and MODIS NDVI. However, spatial variations in the relationship in terms of land-cover and mean NDVI are pointed out. The potential of atmospheric corrections applied to AVHRR data through a radiative transfer atmospheric correction model to improve the relationship between the two NDVI datasets is also investigated. The importance of geo-location accuracy of the AVHRR NDVI dataset is assessed in the light of the accuracy obtainable with the proposed method to estimate a MODIS-equivalent NDVI from the AVHRR NDVI. A method to estimate the MODIS NDVI from the AVHRR NDVI that takes the mean AVHRR NDVI value into account, as opposed to a constant linear relationship over all the points, is proposed. Atmospheric correction is shown not to improve the accuracy of the method in a statistically significant way. The root-mean-square error of the proposed method is in the order of 0.05 NDVI units and varies between 0.5 and 2 standard deviations of the MODIS NDVI over an entire season.
Shin, Shu-Chi, and 施淑琪. "The Impact of 2005 Early Spring Cold on Normalized Difference Vegetation Index (NDVI) at Lien-hua-chi Experimental Forest." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/10294603506350455485.
Full text國立彰化師範大學
地理學系
94
The growth and distribution of plants are strongly affected by temperature. During March 5~9 2005 Taiwan experienced strong cold current. The daily lowest temperature during the period was the lowest at Lien-hua-chi Experimental Forest since 1961 when the regular monitoring of weather started. The lowest temperature was 1oC at an elevation of 520 m above sea level and should be below 0oC at higher elevations. We analyzed the SPOT images of Lien-hua-chi Expereimental Forest of 30 December 2003, 26 February 2004, 13 March 2004, 29 December 2004, 7 March 2005, and 17 March 2005. We calculate normalized difference vegetation index (NDVI) and its changes to detect low temperature induced temporal and spatial changes in vegetation cover and evaluate the responses of different forest stands to the low temperature. Results indicate that vegetative cover was high, but standard deviation of the NDVI is also high possibly due to anthropogenic activities in the low elevation river valley. Following early spring cold in 2005, the NDVI decreased 6.1%, indicating strong influences of the extreme low temperature. The NDVI during the low temperature period was higher than after disturbance indicating a delay in the response of plants to low temperature possibly because it takes time for the leaves to turn yellow and drop. Spatially, the early spring low temperature resulted in higher drop in NDVI at high elevations than low elevations and the increase in NDVI between winter and spring was also higher at high elevations. Elevation is likely crucial to patterns of low temperature damages at Lien-hua-chi.Experimental Forest. The trend of NDVI change in relation to low temperature was consistent between different forest stands, but the degree of damage differed substantially among stands. The decrease in NDVI was twice as high in nature broadleaf forest as in conifer plantations. The results indicate that the natural hardwood forest that adapted to subtropical climate was more sensitive to the low temperature than the conifer plantations that were adapted to climate of the temperate region. Long-term monitoring of vegetation cover together with phonological studies are necessary to evaluate the influences of global change and extreme climate events on plant growth and distribution.
Penedos, Pedro Pais. "Precision Agriculture Using Unmanned Aerial Systems: Mapping Vigor’s Spatial Variability On Low Density Agricultures Using a Canopy Pixel Classification And Interpolation Model." Master's thesis, 2018. http://hdl.handle.net/10362/33277.
Full textIt is becoming more present in agriculture’s practices the use of Unmanned Aerial Systems with sensors capable of capturing light, in the visible and in longer wavelengths of the electromagnetic spectrum once reflected on the field. These sensors have been used to perform Remote Sensing also in other knowledge fields, describing phenomenon without the risk, cost and the time consuming processes associated with in site samples collection and analysis by a technician or satellite imagery acquisition. The Vegetation Indexes developed can explain the vigor of the cultivation and its data collection processes are more cost and time efficient, allowing farmers to monitor plant grow in every critical stage. These Vegetation Indexes started by being calculated from satellite and airborne imagery, one of the main source for crop management tools, however UAS is becoming more present in Precision Agriculture, achieving better spatial and temporal resolution. This gap in spatial resolution when studying low density cultivations like olive groves and vineyards, creates Vegetation Index’s maps polluted with noise caused by the soil and therefore difficult to interpret and analyse. Hence, when the agriculture has spaced and low density vegetation becomes challenging to understand and extract information from these vegetation index’s maps regarding different spatial variability patterns of the tree canopy vigor. In these cases, where vegetation is spaced it is important to filter this noise. A Classification Model was developed with the objective of extracting just the vegetation’s canopy data. The soil was filtered and the canopy data interpolated using spatial analysis tools. The final interpolated maps produced can provide meaningful information regarding the spatial variability and be used to support decision making, identifying critical areas to be intervened and managed, or be used as an input for Variable Rate Technology applications.
Holzapfel, Christopher Brian. "Estimating nitrogen fertilizer requirements of canola (Brassica napus L.) using sensor-based estimates of yield potential and crop response to nitrogen." 2008. http://hdl.handle.net/1993/2996.
Full textFebruary 2008
Almeida, Julio Augusto Pires. "Use of infrared thermometry to measure canopy-air temperature difference at partial cover to assess crop water stress index." 1986. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1986_242_sip1_w.pdf&type=application/pdf.
Full textMekuria, Elias Fekade. "Spatial and temporal analysis of recent drought using vegetation temperature condition index: case of Somali regional state of Ethiopia." Master's thesis, 2012. http://hdl.handle.net/10362/8317.
Full textThe semiarid and arid areas of the eastern part of Ethiopia have suffered a series of droughts and famines in the years 1999/2000, 2003/2004, 2007 and 2011. Absence/decline of rainfall in two of the rainy seasons locally called Dihra and Gu as being the major fact behind drought. Besides, lack of appropriate monitoring techniques aggravate the situation of drought in the study area. In a region where the numbers of meteorological stations are not sufficient enough to monitor the onset and extent of drought, remotely sensed data presents fast and economical way of information as the ground condition reflects the overall condition of rainfall and soil moisture. In this study, the drought monitoring approach is developed using Terra-MODIS Normalized Difference Vegetation index (NDVI) and Land surface Temperature (LST) level-3 products. The approach integrates the land surface reflectance and thermal properties as well as the NDVI changes to identify the extent and pattern of the past drought years. From the NDVI versus LST scatter plot, we extract Vegetation Temperature condition index (VTCI) to map the variability and trend of the drought years. The year 2003 was found to be the driest year (more than 90% of the region affected by drought) and the season that showed increasing intensity of drought being Dihra. The correlation (r > 0.7) between rainfall and VTCI across the major meteorological stations suggested that the index could be used as good indicator of drought as rainfall does. The overall trend of drought condition for selected drought years suggested that eastern and southern regions will experience more severe drought in the coming year. Moreover, VTCI value for October from 2000-2011 showed similar increase intensity of drought condition. In addition, it was observed that sparse vegetation and shrub land are highly variable and bare soil region is consistently dry. Wetter regions were found in the area where the elevation is above 1500m above sea level.
Sigdel, Ganesh Prasad. "Informal settlement segmentation using VHR RGB and height information from UAV imagery: a case study of Nepal." Master's thesis, 2021. http://hdl.handle.net/10362/113715.
Full textInformal settlement in developing countries are complex. They are contextually and radiometrically very similar to formal settlement. Resolution offered by Remote sensing is not sufficient to capture high variations and feature size in informal settlements in these situations. UAV imageries offers solution with higher resolution. Incorporating UAV image and normalized DSM obtained from UAV provides an opportunity of including information on 3D space. This can be a crucial factor for informal settlement extraction in countries like Nepal. While formal and informal settlements have similar texture, they differ significantly in height. In this regard, we propose segmentation of informal settlement of Nepal using UAV and normalized DSM, against traditional approach of orthophoto only or orthophoto and DSM. Absolute height, normalized DSM(nDSM) and vegetation index from visual band added to 8 bit RGB channels are used to locate informal settlements. Segmentation including nDSM resulted in 6 % increment in Intersection over Union for informal settlements. IoU of 85% for informal settlement is obtained using nDSM trained end to end on Resnet18 based Unet. Use of threshold value had same effect as using absolute height, meaning use of threshold does not alter result from using absolute nDSM. Integration of height as additional band showed better performance over model that trained height separately. Interestingly, benefits of vegetation index is limited to settlements with small huts partly covered with vegetation, which has no or negative effect elsewhere.
Arsiso, Bisrat Kifle. "Trends in climate and urbanization and their impacts on surface water supply in the city of Addis Ababa, Ethiopia." Thesis, 2017. http://hdl.handle.net/10500/23592.
Full textEnvironmental Sciences
Ph. D. (Environmental Management)