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1
Oliver, Sophia. "Modelling studies of the atmospheric tides". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365773.
Testo completo
2
Kovalam, Sujata. "MF radar observations of tides and planetary waves". Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phk878.pdf.
Testo completoAbstract (sommario):
Copies of previously published articles inserted. Bibliography: p. 185-200. Data obtained from six radar stations covering a wide latitude range has been used to determine the global distribution of planetary waves and tides. In the process a number of data analyses techniques were considered for their characterisation.
3
Mertz, Gordon James. "Atmospheric and oceanic 40- to 50-day oscillations in the source region of the Somali Current". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25933.
Testo completoAbstract (sommario):
Current and temperature data were acquired in the source region of the Somali Current, jointly by the Universities of Kiel and Miami, as part of the INDEX pilot studies. The data were acquired over a six-month period (January-July, 1976) which spans the springtime Monsoon reversal. The experiment and the data are described in Düing and Schott (1978).
This thesis describes the results of the spectrum analysis of fluctuations found in data from the experiment's two southernmost sensor locations. It is found that, once the annual cycle is removed, most of the variance in these current and temperature records resides in subinertial fluctuations. The most prominent spectral feature is a 40- to 50-day peak.
This 40- to 50-day period is coincident with that of the global-scale circulation cells found in the tropical atmosphere by Madden and Julian (1971 and 1972). The analysis of wind stress and wind stress curl data for the years 1976 and 1979 presented in this thesis indicate that the 40-to 50-day oscillation was present over the Western Indian Ocean during these years. It is suggested here that wind-forcing excites a long coastally trapped wave. To test this idea, a wind-forced quasi-geostrophic, three-layer model and a reduced-gravity model incorporating lateral mean current shear are applied to the Somali Current regime. Model results suggest that the wind forcing is strong enough to excite the observed current and temperature fluctuations.Science, Faculty of
Physics and Astronomy, Department of
Graduate
4
Wood, Andrew Richard. "Theoretical studies of atmospheric tides for the interpretation of satellite data". Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359582.
Testo completo
5
Yagai, Isamu. "NUMERICAL SIMULATION OF ATMOSPHERIC THERMAL TIDES WITH A GENERAL CIRCULATION MODEL". Kyoto University, 1991. http://hdl.handle.net/2433/168744.
Testo completoAbstract (sommario):
本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・論文博士
博士(工学)
乙第7629号
論工博第2514号
新制||工||853(附属図書館)
UT51-91-T435
(主査)教授 加藤 進, 教授 深尾 昌一郎, 教授 桜井 健郎
学位規則第4条第2項該当
6
Sridharan, S. "Investigation of middle atmospheric winds, waves and tides from low latitudes". Thesis, Indian Institute of Geomagnetism, Mumbai, 2002. http://localhost:8080/xmlui/handle/123456789/221.
Testo completo
7
Sridharan, S. "Investigation of middle atmospheric winds, waves and tides from low latitudes". Thesis, IIG, 2002. http://localhost:8080/xmlui/handle/123456789/1604.
Testo completoAbstract (sommario):
A Thesis submitted to the Moanonmaniam Sundaranar University, Tirunelveli, in partial fulfilment of the requirements for the Ph.D. degree under the guidance of Dr. S. Gurubaran, Equatorial Geophysical Research Laboratory, Tirunelveli and Dr. N. Arunachalam, M.S. University, Tirunelveli
8
Stine, Alexander 1973. "A survey of internal tides as seen in moored buoy records". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/29579.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, June 2003.Includes bibliographical references (leaves 139-144).
We estimate the vertical structure of tidal frequency energy at various locations in the ocean by decomposing current records from the WHOI moored buoy archive. Estimates are made of the barotropic and baroclinic modes 1-4 for multiple locations, primarily in the North Atlantic and North Pacific. Estimates are also made for energy flux rates at some locations. The implied global dissipation rate fro the internal tides is significantly below estimates from altimetry.
by Alexander Stine.
S.M.
9
Baumgaertner, Andreas Josef Gerhard. "Observations of Middle Atmosphere Dynamics over Antarctica". Thesis, University of Canterbury. Physics and Astronomy, 2007. http://hdl.handle.net/10092/1397.
Testo completoAbstract (sommario):
This thesis is concerned with the dynamics of the middle atmosphere over the southern-most continent on our planet, Antarctica. Building on previous observational and theoretical efforts to understand the dynamics of this region of the atmosphere, the work encompasses instrument improvements as well as data analysis studies of gravity waves in the lower and middle stratosphere, tides in the upper mesosphere and lower thermosphere, and short-period planetary waves in the stratosphere and mesosphere. An upgrade of the Medium-Frequency Spaced Antenna (MFSA) radar at Scott Base, Antarctica, was carried out in 2004/5 in order to ensure continued operation and enhance its capabilities to measure gravity waves. As a result, the quality of the wind measurements was greatly enhanced and the amount of data collected is now greater by a factor of approximately 15 compared with before the upgrade. Analysis of over two decades of wind velocity data from Scott Base yields a reliable climatology of the dynamics of the upper mesosphere and lower thermosphere in this area, namely the tidal oscillations and the background winds. In addition, interannual variability is assessed and periodicities of approximately 11 years and strong positive trends in tidal amplitudes are reported. Mechanisms that could explain the observed behaviour are proposed. The data are then combined with wind measurements from Halley, the longitudinal conjugate site, in order to study the zonal character of the semi-diurnal tide. Zonal wavenumber 1 and 2 waves are both found and mechanisms that could explain the generation of a wavenumber 1 component are suggested. Two further sets of MFSA radar wind measurements are used to investigate the behaviour of planetary waves with periods of between two and four days in the Antarctic middle atmosphere. Satellite temperature measurements further help to create a more complete picture of these waves. Baroclinic and barotropic instabilities, which result from shears of the zonal wind, appear to be responsible for much of the observed wave activity. In addition, a quasi-to day wave event in mid-May 2005 with unusually large amplitudes is examined and suggested to be linked to a solar proton event. Gravity wave activity over Antarctica is studied using temperature profiles obtained through the satellite radio occultation technique. Although the measurements are restricted to below 35 km altitude, high-resolution temperature profiles allow conclusions to be drawn about the seasonal, geographical, and height distribution of gravity wave activity. Mountain waves are found to be important over the Antarctic Peninsula and the Transantarctic mountains where they contribute more than 20% of the observed wave activity in the lower stratosphere. In addition, the analysis indicates the importance of critical-level filtering and Doppler-shifting.
10
Kim, Sungphil. "Internal Tides and Internal Solitary Waves in the Northern South China Sea". NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-05152009-141246/.
Testo completoAbstract (sommario):
Large-amplitude internal solitary waves (ISWs) are frequently observed in the northern South China Sea (SCS). In a project sponsored by the US Office of Naval Research, four moorings were deployed between the Luzon Strait and the Chinese continental shelf by Steve Ramp of the Naval Postgraduate School and David Tang of National Taiwan University from late April 2005 to May 2006. Several CTD sections were taken during April and July in 2005. Satellite pictures were also collected during that period. In this study, these data were used to examine the characteristics, generation, and propagation of ISWs. In the satellite images, monthly change in stratification may cause northward shift of the propagation path, and ISWs are more frequently observed in July than in April and May. Speed estimation shows that ISWs propagate faster in the deep basin than over the continental margin and near the ridge. The generation of internal tides correlates with the eastward tidal flow over the ridge, while ISWs are produced by northwestward tidal currents over the ridges in the Luzon Strait.
11
Phillips, A. "Dynamics of the Antarctic mesosphere and lower thermosphere /". Title page, contents and abstract only, 1989. http://web4.library.adelaide.edu.au/theses/09PH/09php5583.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Adelaide, Mawson Institute for Antarctic Research, 1990.Copies of author's previously published articles inserted. Includes bibliographical references (leaves 219-226).
12
Hupe, Patrick [Verfasser], e Markus [Akademischer Betreuer] Rapp. "Global infrasound observations and their relation to atmospheric tides and mountain waves / Patrick Hupe ; Betreuer: Markus Rapp". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1182228437/34.
Testo completo
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Tracy, Brian David. "Lunar Tidal Effects in the Electrodynamics of the Low-Latitude Ionosphere". DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1968.
Testo completoAbstract (sommario):
We used extensive measurements made by the Jicamarca Unattended Long-Term Investigations of the Ionosphere and Atmosphere (JULIA) and Incoherent Scatter Radar (ISR) systems at Jicamarca, Peru during geomagnetic quiet conditions to determine the climatologies of lunar tidal effects on equatorial vertical plasma drifts. We use, for the first time, the expectation maximization (EM) algorithm to derive the amplitudes and phases of the semimonthly and monthly lunar tidal perturbations. Our results indicate, as expected, lunar tidal effects can significantly modulate the equatorial plasma drifts. The local time and seasonal dependent phase progression has been studied in much more detail than previously and has shown to have significant variations from the average value. The semimonthly drift amplitudes are largest during December solstice and smallest during June solstice during the day, and almost season independent at night. The monthly lunar tidal amplitudes are season independent during the day, while nighttime monthly amplitudes are largest and smallest in December solstice and autumnal equinox, respectively. The monthly and semimonthly amplitudes decrease from early morning to afternoon and evening to morning with moderate to large increases near dusk and dawn. We also examined these perturbation drifts during periods of sudden stratospheric warmings (SSWs). Our results show, for the first time, the enhancements of the lunar semimonthly tidal effects associated with SSWs to occur at night, as well as during the day. Our results also indicate during SSWs, monthly tidal effects are not enhanced as strongly as the semimonthly effects.
14
Moskowitz, Benjamin M. "An analysis of frictional feedback in the Madden-Julian oscillation /". Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/6791.
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15
Jonsson, Andreas. "Modelling the middle atmosphere and its sensitivity to climate change". Doctoral thesis, Stockholm University, Department of Meteorology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-769.
Testo completoAbstract (sommario):
The Earth's middle atmosphere at about 10-100 km has shown a substantial sensitivity to human activities. First, the ozone layer has been reduced since the the early 1980s due to man-made emissions of halogenated hydrocarbons. Second, the middle atmosphere has been identified as a region showing clear evidence of climate change due to increased emissions of greenhouse gases. While increased CO2 abundances are expected to lead to a warmer climate near the Earth's surface, observations show that the middle atmosphere has been cooling by up to 2-3 degrees per decade over the past few decades. This is partly due to CO2 increases and partly due to ozone depletion.
Predicting the future development of the middle atmosphere is problematic because of strong feedbacks between temperature and ozone. Ozone absorbs solar ultraviolet radiation and thus warms middle atmosphere, and also, ozone chemistry is temperature dependent, so that temperature changes are modulated by ozone changes.
This thesis examines the middle atmospheric response to a doubling of the atmospheric CO2 content using a coupled chemistry-climate model. The effects can be separated in the intrinsic CO2-induced radiative response, the radiative feedback through ozone changes and the response due to changes in the climate of the underlying atmosphere and surface. The results show, as expected, a substantial cooling throughout the middle atmosphere, mainly due to the radiative impact of the CO2 increase. Model simulations with and without coupled chemistry show that the ozone feedback reduces the temperature response by up to 40%. Further analyses show that the ozone changes are caused primarily by the temperature dependency of the reaction O+O2+M->O3+M. The impact of changes in the surface climate on the middle atmosphere is generally small. In particular, no noticeable change in upward propagating planetary wave flux from the lower atmosphere is found. The temperature response in the polar regions is non-robust and thus, for the model used here, polar ozone loss does not appear to be sensitive to climate change in the lower atmosphere as has been suggested recently. The large interannual variability in the polar regions suggests that simulations longer than 30 years will be necessary for further analysis of the effects in this region.
The thesis also addresses the long-standing dilemma that models tend to underestimate the ozone concentration at altitudes 40-75 km, which has important implications for climate change studies in this region. A photochemical box model is used to examine the photochemical aspects of this problem. At 40-55 km, the model reproduces satellite observations to within 10%, thus showing a substantial reduction in the ozone deficit problem. At 60-75 km, however, the model underestimates the observations by up to 35%, suggesting a significant lack of understanding of the chemistry and radiation in this region.
16
Vichare, Geeta. "Theoretical modelling of low latitude current system". Thesis, Indian Institute of Geomagnetism, Mumbai, 2001. http://localhost:8080/xmlui/handle/123456789/210.
Testo completo
17
Flora, Megan. "Diel, Tidal, and Sex Based Differences in Time Spent Feeding by the Florida Manatee (Trichechus manatus latirostris)". NSUWorks, 2012. http://nsuworks.nova.edu/occ_stuetd/190.
Testo completoAbstract (sommario):
The feeding behavior of an animal is based on adaptations to the environment and the animal’s body condition. The Florida manatee (Trichechus manatus latirostris) is an example of a marine mammal that may alter its feeding pattern based on diel and tidal cycles. The increased presence of boats during the day could potentially cause manatees to alter their feeding rates, or the time spent feeding per hour, over the diel cycle. Tide levels may cause manatees to be restricted from areas of preferred vegetation. In addition, the differential reproductive investment between males and females may cause differential time dedicated to feeding between the sexes. This study analyzed sound recordings (lasting up to 24 hr) from manatees tagged in southwest Florida with a digital acoustic recording tag (DTAG) between April and September. Distinctive chewing sounds were indicative of feeding activity. Variation in time spent feeding was analyzed in relation to time of day, sex, female reproductive status, and water level as affected by tides. Manatees dedicated 26% of the time (6 hours) to feeding, on average. During the first year of the study, manatees spent 39% of the time feeding (9 hours), on average, over the course of a 24-hour period; during the second year they spent 15% (2 hours) over the course of a 13-hour daytime period. Adult females fed significantly more, on average, than adult males. Females in late-term pregnancy appeared to spend more time foraging than other non-lactating females, but the sample size was too small to be definitive. Manatee time spent feeding was not correlated with time of day. Increases in feeding activity occurred at mid to high tide levels. This may indicate that manatees had greater access to preferred food sources at this time. An understanding of when manatees 5 are most likely to be feeding and which environmental factors influence this activity may suggest ways to reduce impacts on the endangered population.
18
Soto, Ramos Inia Mariel. "Harmful Algal Blooms of the West Florida Shelf and Campeche Bank: Visualization and Quantification using Remote Sensing Methods". Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4775.
Testo completoAbstract (sommario):
Harmful Algal Blooms (HABs) in the Gulf of Mexico (GOM) are natural phenomena that can have negative impacts on marine ecosystems on which human health and the economy of some Gulf States depends. Many of the HABs in the GOM are dominated by the toxic dinoflagellate Karenia brevis. Non-toxic phytoplankton taxa such as Scrippsiella sp. also form intense blooms off the Mexican coast that result in massive fish mortality and economic losses, particularly as they may lead to anoxia.
The main objectives of this dissertation were to (1) evaluate and improve the techniques developed for detection of Karenia spp. blooms on the West Florida Shelf (WFS) using satellite remote sensing methods, (2) test the use of these methods for waters in the GOM, and (3) use the output of these techniques to better understand the dynamics and evolution of Karenia spp. blooms in the WFS and off Mexico.
The first chapter of this dissertation examines the performance of several Karenia HABs detection techniques using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images and historical ground truth observations collected on the WFS from August 2002 to December 2011. A total of 2323 in situ samples collected by the Florida Fish and Wildlife Research Institute to test for Karenia spp. matched pixels with valid ocean color satellite observations over this period. This dataset was used to systematically optimize variables and coefficients used in five published HAB detection methods. Each technique was tested using a set of metrics that included the F-Measure (FM). Before optimization, the average FM for all techniques was 0.47. After optimization, the average FM increased to 0.59, and false positives decreased ~50%. The addition of a Fluorescence Line Height (FLH) criterion improved the performance of every method. A new practical method was developed using a combination of FLH and Remote Sensing Reflectance at 555 nm (Rrs555-FLH). The new method resulted in an FM of 0.62 and 3% false negatives, similar to those from more complex techniques. The first chapter concludes with a series of recommendations on how to improve the detection techniques and how to take these results a step further into a Gulf wide observing systems for HABs.
In chapter two, ocean color techniques were used to examine the extension, evolution and displacement of four Karenia spp. events that occurred in the WFS between 2004 and 2011. Blooms were identified in the imagery using the new Rrs-FLH method and validated using in situ phytoplankton cell counts. The spatial extension of each event was followed in time by delineating the blooms. In 2004 and 2005, the WFS was affected by a series of hurricanes that led to high river discharge and intense sediment resuspension events. Both processes had an impact on HAB occurrence. For example, I tracked a Karenia spp. bloom found in late December 2004 approximately 40-80 km offshore Saint Petersburg, which then expanded reaching an extension of >8000 km2 in February 2005. The bloom weakened in spring 2005 and intensified again in summer reaching >42,000 km2 after the passage of hurricane Katrina in August 2005. This bloom covered the WFS from Charlotte Harbor to the Florida Panhandle. Two other cases were studied in the WFS. The results of the Hybrid Coordinate Ocean Model from the U.S. Navy aid understanding the dispersal of the blooms.
During fall 2011, three field campaigns to study HABs in Mexico were conducted to do an analysis of optical properties and explore the possibility of using ocean color techniques to distinguish between the main phytoplankton blooms in that region. Three main bloom scenarios were observed in the Campeche Bank region: massive diatom blooms, blooms dominated by Scrippsiella spp., and Karenia spp. blooms. The normalized specific phytoplankton absorption spectra were found to be different for Karenia spp. and Scrippsiella sp. blooms. A new technique that combines phytoplankton absorption derived from MODIS data and the new technique developed in Chapter One showed potential for a detection technique that can distinguish between Karenia and Scrippsiella blooms.
Additional work is needed to improve the new technique developed for Mexican waters, but results show potential for detection techniques that can be used Gulf-wide. This will help better understand the dynamic and possible connectivity of phytoplankton blooms in the GOM.
19
Engel, Patricia Ann. "Spatial and temporal variability of tide-induced salt flux in a partially mixed estuary". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54845.
Testo completoAbstract (sommario):
Thesis (S. M.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 41-43).
Mechanisms for the tidal component of salt flux in the Hudson River estuary are investigated using a 3D numerical model. Variations with river discharge, fortnightly tidal forcing, and along channel variability are explored. Four river discharge conditions were considered: 1200 m3 s-1, 600 m3 s-1, 300 m3 s-1, 150 m3 s-1. Tide-induced residual salt flux was found to be variable along the channel, with locations of counter-gradient flux during both neap and spring tide. The magnitude of tidal salt flux scales with the river flow and has no clear dependence on the spring-neap tidal forcing. The diffusive fraction, ?, has a value of -0.25 to 0.46 in the lower estuary, increasing to -0.23 to 1 near the head of salt. The phase lag between tidal salinity and velocity is analyzed at three cross-sections with: large positive, negative, and weak tidal salt flux. The composite Froude number, G2, is calculated along the channel and indicates nearly ubiquitous supercritical flow for maximum flood and ebb during both neap and spring tides. Subcritical flow occurs during slack water and at geographically locked locations during neap floods. Application of two-layer, frictional hydraulic theory reveals how variations in channel width and depth generate tidal asymmetries in cross-sectional salinity, the key ingredient of tidal salt flux.
by Patricia Ann Engel.
S.M.
20
Borges, Fabricio Batista. "Variações nas marés atmosféricas e nos ventos meteóricos observados em São João Do Cariri-PB e em Cachoeira Paulista-SP". Universidade Estadual da Paraíba, 2010. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2170.
Testo completoAbstract (sommario):
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Previous issue date: 2010-04-04Meteor wind measurements obtained from São João do Cariri B and Cachoeira Paulista SP, Brazil, obtained during the period from August 2004 to July 2006 were used to examine Variations in atmospheric tides and winds in the mesopause region of the equatorial and low Latitudes in the southern hemisphere. The results for the mean wind were compared with the HWM 93 and HWM 07 models (Horizontal neutral wind model) and the results of Atmospheric tides with GSWM 02 model (Global Scale Wave Model). From the analysis of These data it was observed that the mean wind, as well as diurnal fluctuations, showed Temporal and in altitude variations for both the zonal and to the south for both the localities investigated. Mean zonal winds for the region of the S. J. do Cariri show a structure that is characterized by a semi annual oscillation, with a flow westward most of the time, in accordance with HWM 07 model. The mean zonal wind at C. Paulista is eastward in the most time and presents a semi annual variation in the 80 90 km altitude range and an annual variation in the altitudes above, in which some aspects are in accordance with HWM 93 and 07 models. The amplitudes of the mean meridional winds were weaker than zonal and present An annual variation for both sites, which are in accordance with HWM 93 model, however the HWM 07 do not reproduce the observed behavior. The meridional diurnal tide amplitudes Showed semi annual variation with maximum of the up to 65 m/s during February April and August September. The vertical wavelength estimated reached values between 21.2 and 27.5 Km at S. J. do Cariri, smaller than the GSWM 02, whereas to C. Paulista the vertical Wavelength were determined between 24 and 31.9 km, near of the GSWM 02 model, but More than the diurnal tide meridional wavelength for Cariri.
Medidas de vento meteóricos obtidos em São João do Cairi-PB e Cachoeira Paulista-SP Brasil, realizadas durante o período compreendido entre agosto de 2004 a julho de 2006, foram usadas para investigar as variações nas marés atmosféricas e nos ventos meteóricos na região da mesopausa equatorial e de baixas latitudes do hemisfério sul. Os resultados obtidos para os ventos médios foram comparados com os modelos HWM 93 e HWM 07 (Horizontal Neutral Wind Model) e os resultados das marés atmosféricas com GSWM 02 (Global Scale Wave Model). A partir da análise destes dados, foi possível observar que os ventos médios, Assim como as oscilações diurnas, apresentaram variação temporal e em função da altura, tanto para a componente zonal como para a meridional para ambas as localidades investigadas. Os ventos médios na direção zonal para região de S. J. do Cariri mostram uma estrutura que é Caracterizada por uma oscilação semi anual, apresentando um escoamento para oeste na maior Parte do tempo, semelhante com o modelo HWM 07. Já o vento médio zonal verificado na Região de C. Paulista é predominante para leste com variação semi anual entre 80 e 90 km e Anual nas altitudes acima, semelhante em alguns aspectos com os modelos HWM 93 e 07. O Escoamento médio na direção meridional apresenta amplitudes menores do que as do zonal e Oscilação anual para ambas as localidades, a qual é semelhante com o modelo HWM 93, Porém o modelo HWM 07 não reproduz o comportamento observado. As amplitudes da maré Diurna para a componente meridional mostraram variação semi anual com máximos de até 65 m/s em fevereiro abril e agosto setembro. Comprimentos de onda vertical para a componente meridional foram estimados entre 21,2 e 27,5 km para S. J. do Cariri, menores do que as observadas pelo modelo GSWM 02, enquanto que para C. Paulista os comprimentos de onda assumiram valores entre 24 e 31,9 km, próximos aos previstos, porém maiores do que os de Cariri.
21
Bellisario, Christophe. "Modélisation du rayonnement proche infrarouge émis par la haute atmosphère : étude théorique et observationnelle". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLV027/document.
Testo completoAbstract (sommario):
Le rayonnement atmosphérique appelé nightglow est un phénomène se produisant à haute altitude (environ 90 km). Il consiste en l’émission d’un rayonnement suite à la désexcitation de certaines molécules et atomes (OH, Na, O2 et O). Il se répartit sur une large gamme spectrale, en particulier dans l’infrarouge et se propage jusqu’au niveau du sol. Le rayonnement nightglow constitue un marqueur important pour la haute atmosphère, permettant de remonter à la température, mais également à de nombreux phénomènes dynamiques comme les marées atmosphériques ou les ondes de gravité. Sa propagation au niveau du sol permet l’éclairage de scène terrestre et ainsi la vision nocturne à l’aide de caméras proche infrarouge. Afin de mieux connaître les fluctuations de ces émissions en fonction du temps à différentes échelles et en différents lieux sur la planète, la thèse s’est axée sur une étude observationnelle et une étude théorique. L’étude observationnelle a produit une climatologie à grande échelle par l’extraction du rayonnement issu des données de l’instrument GOMOS. Les campagnes de mesures réalisées au sol ont quant à elles mis en avant certains aspects dynamiques importants comme les marées et les ondes de gravité. Pour reproduire le rayonnement nightglow, il a été nécessaire de modéliser les réactions chimiques des nombreuses espèces présentes à haute altitude, le chauffage, la photodissociation de certaines molécules par le rayonnement solaire et la propagation du rayonnement vers le sol. Certains processus dynamiques ont été inclus comme la diffusion moléculaire, la diffusion turbulente et une paramétrisation des marées. Enfin, les résultats du modèle sont comparés aux observations satellitaires ainsi qu’au niveau du sol et des tests de sensibilité sont effectués pour estimer la réponse du rayonnement aux différents modules du modèleThe nightglow is an atmospheric radiation which occurs at high altitude (around 90 km). It comes from the desexcitation of specific molecules and atoms (OH, Na, O2 and O). It spreads over a wide spectral band, especially in the infrared and propagates to the ground level. The nightglow emission is an important mark for the high atmosphere, as it allows the retrieval of the temperature and many dynamic processes such as atmospheric tides or gravity waves. Its propagation to the ground level allows the illumination of terrestrial scene and therefore the night vision with the use of near infrared cameras. In order to have a better knowledge of the emission fluctuations as a function of time for various scales and at various locations, the work is focused on an observational and theoretical study. The observational study produced large scale climatology with the extraction of nightglow emission from GOMOS data. On the other hand, ground measurements highlighted some dynamical aspects such as tides and gravity waves. To model the nightglow emission, it has been necessary to take into account the chemical reactions of the species available at high altitude, the heating, the photodissociation process and the propagation of the emission to the ground. Selected dynamical processes have been included, such as the molecular and turbulent diffusion, and a tide parameterization. Finally, the results of the model are compared to the satellite and ground observations and sensitivity tests are run to estimate the response of the emission to the various modules of the model
22
Muller-Wodarg, Igo Carl Friedrich. "Modelling tides propagating through the menopause into the earth's upper atmosphere". Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268013.
Testo completo
23
Withers, Paul G. "Tides in the Martian atmosphere, and other topics". Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/289910.
Testo completoAbstract (sommario):
The dynamics of the martian upper atmosphere are not well-understood. I have identified the dominant tidal modes present in the upper atmosphere by comparing density measurements from the aerobraking of the Mars Global Surveyor spacecraft to predictions from classical tidal theory. Other observations and general circulation models have also provided constraints. I have presented a justification for why topography has a strong influence on the tides in the upper atmosphere. I have also studied sol-to-sol variations in density at fixed altitude, latitude, longitude, season, and time of day. I have developed a novel "Balanced Arch" technique to derive pressures and temperature from these density measurements that also estimates the zonal wind speed in the atmosphere. These are the first measurements of winds in the martian upper atmosphere. This technique can also be applied to anticipated data from Titan to measure winds in its upper atmosphere. I have developed techniques to derive density, pressure, and temperature profiles from entry accelerometer data, used them to investigate the entry of Mars Pathfinder, and discovered that surprisingly accurate temperature profiles can be derived without using any aerodynamic information at all. I have also investigated techniques to derive atmospheric properties from the Doppler shift in telemetry from a spacecraft during atmospheric entry and found that a surprisingly robust estimate of temperature at peak acceleration can be derived. I have discovered a network of tectonic ridges in the otherwise bland northern plains of Mars and studied their implications for a possible ocean in that area. I have tested the hypothesis that the formation of lunar crater Giordano Bruno was witnessed in 1178 AD and rejected it due to the lack of any observations of the immense meteor storm that must have followed the crater's formation.
24
Löffelmann, J., Friederike Lilienthal e Christoph Jacobi. "Trend analyses of solar tides in the middle atmosphere". Universität Leipzig, 2019. https://ul.qucosa.de/id/qucosa%3A74180.
Testo completoAbstract (sommario):
Using a mechanistic global circulation model, we analysed the trends of
solar tides in the middle atmosphere. Forced by monthly mean assimilation of reanalysis data in the lower atmosphere and monthly adjusted CO2 and ozone distributions, the simulations represent a time period from January 1980 to May 2019. The time series of monthly mean wind and temperature amplitudes of all tidal components have been extracted from these data. Trend analyses by linear regression show prevailing negative trends in July and October for all tides and for all latitudes in the mesosphere and lower thermosphere. In April and January, however, trends are positive or negative, depending on the tidal component. Furthermore, the data set has been examined on possible trend changes via a statistical trend algorithm. A large part of those break points for the zonal wind amplitudes were found from 1985 to 1988 and from 2012 to 2015 for the investigated months January and April. Therefore, a clear relation between changes in the atmospheric ozone concentration and trends of the amplitudes of solar tides is not evident for the presented variables.Unter Verwendung eines mechanistischen globalen Zirkulationsmodells wurden Trends von solaren Gezeiten in der mittleren Atmosphäre analysiert. Die Simulationen, die in den unteren Atmosphärenschichten mit monatlich gemittelten Reanalysedaten angetrieben wurden sowie mit angepassten CO2 und Ozonverteilungen, decken einen Zeitraum von Januar 1980 bis Mai 2018 ab. Aus diesen Daten wurden Zeitreihen für Monatsmittel in den Amplituden des Windes und der Temperatur für alle vier Gezeiten herausgefiltert. Die über lineare Regression gewonnen Trends ergeben -global betrachtet in der Mesosphäre und unteren Thermosphäre - vorwiegend negativsignifikante Trends im Juli und Oktober. Im April und Januar können jedoch je nach Gezeit und Parameter positive wie auch negative Trends vorkommen. Weiterhin wurden die Datenreihen auf mögliche Trendänderungen mit Hilfe eines statistischen Algorithmus untersucht. Ein Großteil dieser Trend-Wendepunkte in den Zonalwindamplituden liegen für die untersuchten Monate Januar und April in den Jahren von 1985 bis 1988 und von 2012 bis 2015. Eine direkte Verbindung zwischen Änderungen in der atmosphärischen Ozonkonzentration und Trends in den Amplituden solarer Gezeiten lassen sich in den hier behandelten Größen daher nicht ableiten.
25
Geißler, Christoph, e Ch Jacobi. "Forcing of the Quarterdiurnal Tide". Universität Leipzig, 2018. https://ul.qucosa.de/id/qucosa%3A31792.
Testo completoAbstract (sommario):
Ensemble calculations for the period from 2000 to 2010 were carried out with the middle and upper atmosphere model (MUAM), and an analysis of the quarterdiurnal tide is performed. The global temporal and latitudinal distributions of the quarterdiurnal tide are modeled with MUAM, and their forcing mechanisms are examined. The quarterdiurnal tides show a similar distribution over the year in the northern and southern hemisphere, with maxima of the amplitude in late winter and spring as well as in autumn. In the latitude-height distribution is also shown that the largest amplitudes of the quarterdiurnal tide are seen at midlatitudes. Due to the decreasing density with height, there is a general increase of the tidal amplitudes with height. The results of the forcing analyses show that direct solar forcing is most important, but also that non-linear forcing and gravity wave interaction with other tides have a non-negligible influence on the quarterdiurnal tide in the middle and upper atmosphere.Mit dem Modell für die mittlere und obere Atmosphäre MUAM wurden Ensemble-Berechnungen für den Zeitraum 2000 bis 2010 durchgeführt und die vierteltägigen Gezeiten analysiert. Es wird auf die globale zeitliche und räumliche Verteilung der vierteltägigen Gezeiten eingegangen und deren Anregungsmechanismen untersucht. Die vierteltägigen Gezeiten zeigen einen ähnlichen Verlauf über das Jahr auf der Nord- und Südhalbkugel mit Maxima der Amplitude im späten Winter und Frühjahr sowie im Herbst. Ein ähnliches Bild zeigt sich auch für die Verteilung im Breiten-Höhen-Schnitt, wo die größten Amplituden der vierteltätigen Gezeiten in den mittleren Breiten zu finden sind. Aufgrund der abnehmenden Dichte mit der Höhe ist eine allgemeine Zunahme der Amplituden mit der Höhe zu beobachten. Es zeigte sich, dass der direkte solare Antrieb am stärksten ausgeprägt ist, aber auch, dass der nichtlinearer Antrieb und die Interaktion von Schwerewellen mit anderen Gezeiten einen nicht zu vernachlässigenden Einfluss auf die vierteltägigen Gezeiten in der mittleren und oberen Atmosphäre haben.
26
Sahu, Parameswar. "Use of Time Series, Barometric and Tidal Analyses to Conceptualize and Model Flow in an Underground Mine: The Corning Mine Complex, Ohio". Ohio University / OhioLINK, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1108395116.
Testo completo
27
Stevens, M. H., D. E. Siskind, J. S. Evans, S. K. Jain, N. M. Schneider, J. Deighan, A. I. F. Stewart et al. "Martian mesospheric cloud observations by IUVS on MAVEN: Thermal tides coupled to the upper atmosphere". AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/624978.
Testo completoAbstract (sommario):
We report observations of Martian mesospheric ice clouds and thermospheric scale heights by the Imaging Ultraviolet Spectrograph on NASA's Mars Atmosphere and Volatile Evolution mission. The clouds are observed between 6A.M. and 8A.M. local time using mid-UV limb observations between 60 and 80km tangent altitude where ice particles that scatter sunlight can appear as detached layers near the equator. The equatorial longitudinal distribution shows populations of clouds near -110 degrees E and -10 degrees E as well as a population near 90 degrees E, which does not have a clear precedent. The cloud populations indicate a wave 3 pattern near 70km, which is confirmed by independent mesospheric temperature observations. Scale heights 100km above the clouds derived from concurrent Imaging Ultraviolet Spectrograph (IUVS) observations also reveal a wave 3 longitudinal structure, suggesting that the temperature oscillations enabling the formation of mesospheric clouds couple to the upper atmosphere. Plain Language Summary The manuscript describes the observation of Martian mesospheric clouds between 60 and 80km altitude by the Imaging Ultraviolet Spectrograph (IUVS) on NASA's MAVEN spacecraft. The cloud observations are uniquely obtained at early morning local times, which complement previous observations obtained primarily later in the diurnal cycle. Differences in the geographic distribution of the clouds from IUVS observations indicate that the local time is crucial for the interpretation of mesospheric cloud formation. We also report concurrent observations of upper atmospheric scale heights near 170 km altitude, which are diagnostic of temperature. These observations suggest that the dynamics enabling the formation of mesospheric clouds propagate all the way to the upper atmosphere.
28
Mathers, Eunice Lucy. "Sea level response to atmospheric pressure and wind forcing in the global deep ocean". Thesis, University of Liverpool, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367977.
Testo completo
29
Kumar, Aishwarya S. "Non-migrating tides in the Martian thermosphere". Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85828.
Testo completoAbstract (sommario):
Previous studies have identified longitudinal structures associated with non-migrating tides in observations of the upper neutral atmosphere of Mars. MAVEN’s Imaging Ultraviolet Spectrometer (IUVS) observations of the upper atmosphere reveal variations in density with longitude at altitudes of 130 – 200 km, and can be used to identify non-migrating tides. These observations cover higher latitudes and allow for studying the local time variations of tides. The analysis presented here shows that the longitudinal structure attributed to non-migrating tides is dominated by wavenumber 2 and wavenumber 3 harmonics during the periods studied. Comparison with the Neutral Ion and Gas Mass spectrometer (NGIMS) shows a good agreement in wave amplitudes observed for the first two cases studied. The temperatures and 𝑂/𝐶𝑂# ratios from the IUVS L2 data files revealed an anti-correlation with the densities which confirms the theoretical interpretation from the linear wave theory.Master of Science
There are waves internal to all fluids in our surroundings and daily lives, such as sound waves. Waves in the atmosphere are also fluid in nature. In planetary atmospheres, the scale sizes of some of these waves become comparable to the size of the planet itself. The waves interact with the structure of the surface of Mars to form a certain type of wave called “Non-migrating tides”. These waves have been observed in multiple previous studies in the upper atmosphere of Mars (~130 km and above). These waves cause the atomic and molecular content of the upper atmosphere to be displaced in a particular manner to form a unique structure. The structures formed are observed on a scale that covers the entire planet. It is by studying these structures in the upper atmosphere that it is possible to characterize the waves that control them and thereby understand their nature and impact. Understanding how these waves vary helps spacecraft to gain better control over mechanisms required to swing them into the desired orbit (location). This study uses the observations from an instrument aboard the MAVEN mission and compares it to the observations from another instrument aboard the same mission. The results of this study demonstrate that these “Non-migrating” tides play a vital role in controlling the behavior of the upper atmosphere.
30
Signell, Richard P. "Tide- and wind-forced currents in Buzzards Bay, Massachusetts". Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/58333.
Testo completoAbstract (sommario):
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1987.Microfiche copy available in Archives and Science.
Bibliography: leaves 83-86.
by Richard Peter Signell.
M.S.
31
Betts, Makayla N. (Makayla Nicole). "Gene transfer history of carbon fixation proteins constrains marine cyanobacteria divergence times". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118026.
Testo completoAbstract (sommario):
Thesis: S.M. in Geophysics, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018.Cataloged from PDF version of thesis. "June 2018."
Includes bibliographical references (pages 18-24).
Carboxysomes provide an avenue for narrowing the timing of evolutionary events in groups of cyanobacteria that are ecologically dominant in modem marine environments - groups that may have an integral role in oxygenating the Earth's atmosphere. Here I show that using concatenated phylogenies of carbon fixation proteins better informs the horizontal gene transfer event that brought carboxysomes from purple sulfur bacteria into marine cyanobacteria and that this gene history aids in constraining the evolutionary timing of carbon fixation. Genes encoding the proteins for the a-carboxysomal shell as well as RuBisCO and carbonic anhydrase are co-located on the genomes of various cyanobacteria in the Prochlorococcus and Synechococcus groups. Previous studies have shown that these genes were likely horizontally transferred together from Chromatiales (purple sulfur bacteria), a group of phototrophic Gammaproteobacteria. While many of these genes are highly conserved and thus yield poorly resolved phylogenies, their concatenation clarifies a shared evolutionary history. This work integrates gene transfer with molecular clock calibration methods to determine divergence times. Accordingly, I evaluate the relationship between atmospheric evolution and the ecology of important groups of phototrophs.
by Makayla N. Betts.
S.M. in Geophysics
32
Thayalan, Vid. "Atmospheric contribution to the dissipation of the gravitational tide of Phobos on Mars". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45790.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2008.Includes bibliographical references (p. 29).
Here, we investigate the possibility of a significant atmospheric contribution to the tidal dissipation of the Phobos-Mars system. We apply the classical tidal theory and we find that most of gravitational forcing is projected into the first symmetric Hough mode which has an equivalent depth of about 57 km and it is significantly trapped in the vertical. Therefore, no significant dissipation occurs through the vertical propagation of energy and subsequent breaking of the tidal wave as the wave amplifies with height. Alternatively, from the energy stored in the first trapped mode we estimate that the time scale required for the dissipative mechanisms to account for the total dissipation of the tides is of order 102s. This time scale is unrealistically short, since it would contradict observations of propagating thermal tides in Mars atmosphere. Therefore we conclude that the dissipation of the tidal potential that explains the observed acceleration of Phobos most likely occurs within the solid planet.
by Vid Thayalan.
S.M.
33
Withnell, Anthony James. "Relative sea-level variations revealed by tide-gauge records of long duration". Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/58421.
Testo completoAbstract (sommario):
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990.Includes bibliographical references (leaves 65-67).
by Anthony James Withnell.
M.S.
34
Medvedev, Alexander S., Hiromu Nakagawa, Chris Mockel, Erdal Yiğit, Takeshi Kuroda, Paul Hartogh, Kaori Terada et al. "Comparison of the Martian thermospheric density and temperature from IUVS/MAVEN data and general circulation modeling". AMER GEOPHYSICAL UNION, 2016. http://hdl.handle.net/10150/614739.
Testo completoAbstract (sommario):
Newly released Imaging Ultraviolet Spectrograph/Mars Atmosphere and Volatile EvolutioN (IUVS/MAVEN) measurements of CO2 density in the Martian thermosphere have been used for comparison with the predictions of the Max Planck Institute Martian General Circulation Model (MPI-MGCM). The simulations reproduced (within one standard deviation) the available zonal mean density and derived temperature above 130 km. The MGCM replicated the observed dominant zonal wave number 3 nonmigrating tide and demonstrated that it represents a nonmoving imprint of the topography in the thermosphere. The comparison shows a great dependence of the simulated density and temperature to the prescribed solar flux, atomic oxygen abundances and gravity wave effects, with the former two being especially important in the thermosphere above 130 km and the latter playing a significant role both in the mesosphere and thermosphere.
35
Fröhlich, Kristina, Alexander Pogoreltsev e Christoph Jacobi. "Tides, Rossby and Kelvin waves simulated with the COMMA-LIM Model". Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-217759.
Testo completoAbstract (sommario):
A 48-layer version of the COMMA-LIM (Cologne Model of the Middle Atmosphere – Leipzig Institute for Meteorology) three-dimensional global mechanistic model of the Earth\'s atmosphere from 0 km to 135 km with logarithmic pressure height coordinates was developed. The model is capable of reproducing the global structures and propagation of different planetary waves in the middle atmosphere. The contribution of gravity waves, tides, Rossby and Kelvin waves into the zonally averaged momentum budget of the mesosphere / lower thermosphere region has been investigatedEine neue Version des COMMA-LIM (Cologne Model of the Middle Atmosphere – Leipzig Institute for Meteorology) wurde im Zusammenhang mit der Erhöhung der vertikalen Schichtauflösung entwickelt. Das COMMA ist ein dreidimensionales globales mechanistisches Modell der Erdatmosphäre mit einer Ausdehnung von ca. 0 – 135 km in logarithmischen Druckkoordinaten. Damit können globale Eigenschaften der mittleren Atmosphäre sowie die Ausbreitung verschiedener planetarer Wellen nachvollzogen werden. Die Beiträge der Schwerewellen, thermischer Gezeiten, Rossby und Kelvin Wellen zur zonal gemitteltem Impulsbalance der Mesosphäre und unteren Thermosphäre wurden untersucht
36
Chang, Loren. "Analysis of the migrating diurnal tide in the Whole Atmosphere Community Climate Model". Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1439426.
Testo completo
37
Fröhlich, Kristina, Alexander Pogoreltsev e Christoph Jacobi. "Tides, Rossby and Kelvin waves simulated with the COMMA-LIM Model". Wissenschaftliche Mitteilungen des Leipziger Instituts für Meteorologie ; 30 = Meteorologische Arbeiten aus Leipzig ; 8 (2003), S. 149-156, 2003. https://ul.qucosa.de/id/qucosa%3A15248.
Testo completoAbstract (sommario):
A 48-layer version of the COMMA-LIM (Cologne Model of the Middle Atmosphere – Leipzig Institute for Meteorology) three-dimensional global mechanistic model of the Earth\''s atmosphere from 0 km to 135 km with logarithmic pressure height coordinates was developed. The model is capable of reproducing the global structures and propagation of different planetary waves in the middle atmosphere. The contribution of gravity waves, tides, Rossby and Kelvin waves into the zonally averaged momentum budget of the mesosphere / lower thermosphere region has been investigated.Eine neue Version des COMMA-LIM (Cologne Model of the Middle Atmosphere – Leipzig Institute for Meteorology) wurde im Zusammenhang mit der Erhöhung der vertikalen Schichtauflösung entwickelt. Das COMMA ist ein dreidimensionales globales mechanistisches Modell der Erdatmosphäre mit einer Ausdehnung von ca. 0 – 135 km in logarithmischen Druckkoordinaten. Damit können globale Eigenschaften der mittleren Atmosphäre sowie die Ausbreitung verschiedener planetarer Wellen nachvollzogen werden. Die Beiträge der Schwerewellen, thermischer Gezeiten, Rossby und Kelvin Wellen zur zonal gemitteltem Impulsbalance der Mesosphäre und unteren Thermosphäre wurden untersucht.
38
Morley, Danielle M. "Environmental Enhancement Gone Awry: Characterization of an Artificial Reef Constructed From Waste Vehicle Tires". NSUWorks, 2009. http://nsuworks.nova.edu/occ_stuetd/231.
Testo completoAbstract (sommario):
In 1967, Broward County, Florida resource managers initiated a project to construct an artificial reef to enhance recreational fishing using waste vehicle tires. An estimated two million unballasted tires were bundles and deployed in bundles approximately 1.8km offshore in 21m of water on sandy substrate separating the middle and outer reef tracts, running parallel to the coast. Over time, bindings on the tire bundles failed and the tires became mobile with normal currents and high energy storms. The tires have apparently moved extensively, travelling kilometers from their original location to beaches and deeper waters offshore. It has also been reported that loose tires have physically damaged benthic reef fauna on the natural reef. Due to this damage, a large-scale removal plan of the tires has been initiated. To assess damage and evaluate effectiveness of tire removal, an examination of existing biota was accomplished. Live corals were absent on the middle reef edge, buried by tires but were present on the tires themselves. When compared to the impacted middle reef edge (tires present), adjacent natural reef control sites (tires absent) exhibited significantly lower fish abundance and species richness. Removal of the tires will directly reduce the abundance of fishes and affect the corals in the area. Future studies will evaluate the loss of these resources relative to the gain in reduced impact to the natural reef.
39
Lilienthal, Friederike, e Christoph Jacobi. "The Role of Solar Heating in the Forcing of the Terdiurnal Tide". Universität Leipzig, 2016. https://ul.qucosa.de/id/qucosa%3A16705.
Testo completoAbstract (sommario):
We use the middle and upper atmosphere model (MUAM) to analyze forcing mechanisms of the terdiurnal tide (TDT) in the middle atmosphere, namely solar heating and nonlinear wave-wave interactions. First, we present model amplitudes of the TDT during January conditions as a validation and for reference. By switching off single forcings for wavenumber 3 in different model runs we are able to separate the solar and nonlinear forcing contribution. The simulations suggest that solar forcing is the major driver for TDT at low latitudes while nonlinear interactions become more important at middle and high latitude, especially in the winter hemisphere. Additionally we observe increased TDT amplitudes for purely solar driven TDTs without nonlinear forcing in some regions which may be owing to destructive interferences.Wir nutzen das Modell für die mittlere und obere Atmosphäre (MUAM), um die Anregungsmechanismen der dritteltägigen Gezeiten, solare Erwärmung und Wechselwirkungen zwischen Wellen, zu analysieren. Zunächst präsentieren wir die modellierten Amplituden der dritteltägigen Gezeiten für Januarbedingungen. Dies dient einerseits der Validierung und andererseits als Referenz. Indem die Wellenzahl 3 in den verschiedenen Anregungstermen in einzelnen Läufen ausgeschalten wird, lassen sich die jeweiligen Beiträge aus solarer und nichtlinearer Anregung separieren. Aus den Simulationen lässt sich ableiten, dass solare Erwärmung den Hauptanteil in niedrigen Breiten bildet, während nichtlineare Wechselwirkungen in mittleren und hohen Breiten immer wichtiger werden, vor allem auf der Winterhemisphäre. Zudem beobachten wir verstärkte Amplituden der dritteltägigen Gezeiten bei ausschließlich solarer Anregung ohne nichtlinearen Anteil, was an destruktiver Überlagerung der Antriebsterme liegen kann.
40
Senf, Fabian [Verfasser], Ulrich [Akademischer Betreuer] Achatz e Erich [Akademischer Betreuer] Becker. "On the interaction between thermal tides and gravity waves in the middle atmosphere / Fabian Senf. Gutachter: Ulrich Achatz ; Erich Becker. Betreuer: Ulrich Achatz". Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2012. http://d-nb.info/1044275669/34.
Testo completo
41
Sandford, David J. "Dynamics of the stratosphere, mesosphere and thermosphere". Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512300.
Testo completoAbstract (sommario):
This thesis presents observations of the dynamical features of the stratosphere, mesosphere and lower thermosphere. These are made from various observational techniques and model comparisons. A focus of the work is the two-day wave at high latitudes in the MLT region. This has revealed significant wave amplitudes in both summer and winter. However, these waves are shown to have very different origins. Using satellite data, the summertime wave is found to be the classic quasi-two-day wave which maximises at mid-latitudes in the MLT region. The wintertime wave is found to be a mesospheric manifestation of an eastward-propagating wave originating in the stratosphere and likely generated by barotropic and baroclinic instabilities in the polar night jet. The horizontal winds from Meteor and MF radars have been used to measure and produce climatologies of the Lunar M2 tide at Esrange in the Arctic (68°N), Rothera and Davis in the Antarctic (68°S), Castle Eaton at mid-latitude (52°N) and Ascension Island at Equatorial latitudes (8°S). These observations present the longest period of lunar semi-diurnal tidal observations in the MLT region to date, with a 16-year dataset from the UK meteor radar. Comparisons with the Vial and Forbes (1994) lunar tidal model are also made which reveal generally good agreement. Non-migrating lunar tides have been investigated. This uses lunar tidal results from equatorial stations, including the Ascension Island (8°S) meteor radar. Also lunar tidal results from the Rothera meteor wind radar (68°S, 68°W) and the Davis MF radar (68°S, 78°E) are considered. Both of these stations are on the edge of the Antarctic continent. It is demonstrated that there are often consistent tidal phase offsets between similar latitude stations. This suggests that non-migrating modes are likely to be present in the lunar semi-diurnal tidal structure and have significant amplitudes.
42
Freitas, Sidcléa Sousa de. "Benefícios sociais e ambientais do coprocessamento de pneus inservíveis: estudo de caso na cidade de João Pessoa-PB". Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/5446.
Testo completoAbstract (sommario):
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Previous issue date: 2010-09-30Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The useless tire is a residue that must be managed correctly until its final disposal as well as its collection and storage must be done adequately. Therefore, if it is inadequately disposed of, it can cause damages to the environment and to public health. In March 2005 the city of João Pessoa, initiated a program called Programa Nordeste Rodando Limpo - Northeastern Program of Clean Twirling - through the partnership between private companies, which consisted of the collection and final destination of the useless tires to be used in the ovens to produce clinker, providing a market value to these residues. This research was developed at CIMPOR, a cement plant located in the city of João Pessoa and has as its objective to make an analysis of the main benefits of the use of theses tires during the co-processing step inside the clinker oven. The methodology applied in this study were based on the qualitative evaluation of the generated benefits to public health and the quantitative social profits generated to the recycling workers and identifying profits with the collection of the tires as well as the increasing of the these workers income. The same research also verified that the co-processing atmospheric emissions and CO2 emissions were prevented during the transportation of the Petroleum coke. This also lessened the involved costs with this process. In all cases, the final results had confirmed the existence of environmental and social benefits in the use of the co-processing system, making possible the withdrawal of 26.568, 90 tons of useless tires that were deposited in the State of Paraiba. Consequently, in neighboring states, it was also verified the automatic creation of a mechanism of collection by the society that made possible economic profits of an estimated R$ 2 million reais to the recycling workers improving their quality of life. Another important data observed in the same study was a gradual increase of the use of useless tires, implying in a lesser consumption of non renewable fuel and the minimization of atmospheric emissions which prevents high levels of CO2 emissions, generally caused by the lesser volume of Petroleum coke produced, also resulting, in the decrease of the production costs.
O pneu inservível é um resíduo que deve ser gerido corretamente até sua disposição final e, deve ser coletado e armazenado adequadamente, pois quando disposto inadequadamente tanto pode causar danos ao meio ambiente quanto à saúde pública. Em João Pessoa foi iniciado, em março de 2005, o Programa Nordeste Rodando Limpo através da parceria entre empresas privadas, que consiste na realização de coleta e destinação final dos pneus inservíveis para utilização nos fornos de fabricação de clínquer, fazendo com que estes passem a ter valor no mercado de resíduos. O estudo foi desenvolvido na Fábrica da CIMPOR localizada na cidade de João Pessoa e tem por objetivo fazer uma análise sobre os principais benefícios da utilização de pneus inservíveis no coprocessamento no forno de clínquer. A metodologia utilizada foi baseada na avaliação qualitativa dos benefícios gerados a saúde pública e quantitativa dos ganhos sociais gerados aos catadores, identificando ganhos com a coleta dos pneus, mensurando o aumento da renda dos mesmos. O referido trabalho também verificou as emissões atmosféricas do coprocessamento e as emissões evitadas de CO2 no transporte do coque de petróleo, além da economia de custos envolvidos com o coprocessamento. Os resultados obtidos confirmaram os benefícios ambientais e sociais no coprocessamento, sendo possível a retirada de 26.568,90 toneladas de pneus inservíveis que estavam depositados no estado da Paraíba e em estados vizinhos, além da criação automática de um mecanismo de coleta pela sociedade, que possibilitou ganhos econômicos da ordem de R$ 2 milhões de reais aos catadores, melhorando assim, sua qualidade de vida. Verificou-se também um gradativo aumento da utilização de pneus inservíveis, implicando em um menor consumo de combustíveis não-renováveis, minimizando emissões atmosféricas e evitando níveis de emissões de CO2, devido ao menor volume de coque transportado, resultando também, na minimização dos custos de produção.
43
Garrett, Matthew. "Influence of Water Column Stratification and Nutrient Gradients on the Migratory Behavior of the Red Tide Dinoflagellate, Karenia brevis". Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5950.
Testo completoAbstract (sommario):
Diel vertical migration (DVM) can offer motile phytoplankton a competitive advantage over other phytoplankton species. DVM has been well documented in the harmful dinoflagellate, Karenia brevis; however, the extent to which changes in nutrient regimes and density stratification modify migration patterns has not been thoroughly investigated. A 2 m experimental column was constructed with sensors and sampling ports at four depths to obtain fluorescence and temperature measurements and discrete water samples. The environmental parameters of the experimental column represented temperature and nutrient conditions found on the West Florida Shelf (WFS), where Karenia blooms frequently occur. Results demonstrated a clear DVM pattern for K. brevis where surface aggregations occurred during light periods, and bottom aggregations occurred in dark periods. However, the rate and intensity of migration varied between experimental conditions. Injections of nutrient replete water at the surface and bottom did not appear to modify migratory behavior, in that a portion of the population resided at depth regardless of light or dark periods. Weak density stratification caused a delay in downward migration in dark periods, whereas strong density stratification caused a complete cessation of downward migration. In a weakly stratified environment with a bottom injected replete water mass, DVM patterns most closely replicate the pattern under weakly stratified conditions alone. Modifications in the natural DVM pattern of K. brevis with respect to varying environmental and nutrient conditions that occur on the WFS can have major implications current forecast model predictions, and for monitoring and mitigation strategies.
44
Beldon, Charlotte. "VHF radar studies of mesosphere and thermosphere". Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512294.
Testo completo
45
Jordan, Anna C. "Patterns in Caribbean Coral Spawning". Thesis, NSUWorks, 2018. https://nsuworks.nova.edu/occ_stuetd/468.
Testo completoAbstract (sommario):
Most corals worldwide are broadcast spawners that rely on synchronous gamete release for successful fertilization. Spawning synchrony may also decrease the probability of heterospecific fertilization that may produce maladaptive hybrids. Despite the importance of reproductive timing, researchers have only recently begun to collect spawning data across coral species in the Caribbean, but these data remain to be analyzed. This study investigates interannual, seasonal, and environmental patterns that may influence Caribbean scleractinian spawning times. The number of spawning observations varies widely among location and species. Most spawning observations were collected in Florida, Curaçao, and Flower Garden Banks National Marine Sanctuary. Acropora palmata, A. cervicornis, and Orbicella species were the most documented. The Orbicella spp. were very consistent for spawning day annually, while the acroporids were less reliable. However, the acroporids were more consistent for spawning time in minutes after sunset between years. Season and moon cycles were obvious proximate cues for spawning, but a strong influence from wind and tides was absent. Acropora cervicornis was the only species in this study which spawning was significantly affected by water temperature. For some scleractinians, the day of spawning was significantly affected by mass bleaching events; spawning could occur on earlier days than in previous years for up to two years after the event. This study highlights existing data gaps for Pseudodiploria clivosa, A. prolifera and Siderastrea siderea. Documenting spawning patterns is crucial to better understand the potential impacts of future threats on the already imperiled Caribbean corals at risk from reproductive failure.
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Arana, Daniel. "A maré terrestre : aspectos teóricos e práticos /". Presidente Prudente, 2020. http://hdl.handle.net/11449/192164.
Testo completoAbstract (sommario):
Orientador: Paulo de Oliveira CamargoResumo: Existem dados de estações de maré terrestre em todo território nacional que estiveram em operação nos últimos anos. Contudo cada região de coleta apresenta um ou mais efeitos geofísicos predominantes, causando uma heterogeneidade dos dados e abrindo a possibilidade para diversos estudos. A minimização de efeitos geofísicos em observações gravimétricas é um grande desafio na geração de modelos de maré terrestre. Desta forma, esta pesquisa tem como objetivo estudar as metodologias para correções das cargas atmosférica e oceânica nos diferentes cenários. A hipótese adotada nesta pesquisa é que a consideração do parâmetro temporal junto à análise espectral possibilita isolar a maré terrestre e as sobrecargas. A metodologia neste trabalho envolve três etapas: (1) o pré-processamento, (2) o processamento das observações gravimétricas e (3) a aplicação dos modelos de marés. As estações base do estudo são PPTE e NEIA, localizadas respectivamente nos municípios de Presidente Prudente - SP e Cananeia - SP, escolhidas em razão do comportamento distinto das cargas oceânicas nas duas regiões. A pesquisa fundamenta-se na decomposição por harmônicos esféricos e pelo uso de ondaletas na série temporal gravimétrica das duas estações. O pré-processamento dos dados foi minuciosamente realizado, destaca-se a detecção de um deslocamento temporal em parte dos dados gravimétricos de PPTE, que foram corrigidos com sucesso. Na etapa do processamento foram analisados os impactos das correções atmosfér... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: There are Earth tide data from stations across the country that have been in operation in recent years. However, each collection region has one or more predominant geophysical effects, causing a heterogeneity of data and opening the possibility for several studies. The minimization of geophysical effects in gravimetric observations is a major challenge in the generation of terrestrial tide models. Thus, this research aims to study the methodologies for correcting atmospheric and ocean loading in different scenarios. The hypothesis adopted in this research is that the consideration of the temporal parameter together with the spectral analysis makes it possible to isolate the terrestrial tide and the overloads. The methodology in this work involves three stages: (1) the pre-processing, (2) the processing of the gravimetric observations and (3) the application of the tidal models. The study stations are PPTE and NEIA, located respectively in the cities of Presidente Prudente - SP and Cananeia - SP, chosen due to the different behavior of ocean loading in the two regions. The research is based on the decomposition by spherical harmonics and the use of wavelets in the gravimetric time series of the two stations. The pre-processing of the data was meticulously carried out, highlighting the detection of a temporal displacement in part of the PPTE gravimetric data, which were successfully corrected. In the processing stage, the impacts of atmospheric and oceanic corrections were anal... (Complete abstract click electronic access below)
Doutor
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El, masri Ahmad. "Étude cinétique et mécanistique de la réactivité des composés organophosphorés avec les photooxydants atmosphériques". Thesis, Reims, 2014. http://www.theses.fr/2014REIMS026/document.
Testo completoAbstract (sommario):
Cette thèse établit le schéma de dégradation hétérogène du chlorpyriphos éthyl (CLP) sous l'action des radicaux OH et de l'ozone pour des dépôts de CLP sur des plaques de quartz et sous celle l'ozone pour différentes contaminations de sable en CLP. Les constantes cinétiques de la dégradation hétérogène sont déterminées dans un réacteur photo-chimique couplé à un système GC/MS. Le chlorpyriphos-oxon (CLPO) et le trichloropyridinol (TCP) sont les produits de dégradation détectés en phase hétérogène quels que soit l'oxydant et le support. La réactivité hétérogène du CLPO vis-à-vis de l’ozone et des radicaux OH est également étudiée. Les résultats montrent que les radicaux OH constituent la principale voie de dégradation hétérogène du CLP et que le CLPO est plus persistant que le CLP. Le CLPO peut être transporté loin de son point d'application. L'ozonolyse hétérogène du CLP sur du sable montre que la cinétique est dépendante de la contamination en CLP de manière exponentielle. Le mécanisme réactionnel établi à partir de l'analyse des produits de dégradation en phase condensée prévoit la formation de petites molécules organophosphorées dont nous avons étudié la réactivité par rapport aux radicaux OH et au chlore atomique en phase gazeuse en fonction de la température. Le O,O,O-triéthylphosphate (TEP) et le diéthyle O,O-diéthyléthylphosphonate (DEEP) présentent des constantes de vitesse de supérieures à 10-10 cm3.molécule-1.s-1. Ces molécules se dégradent donc rapidement dans l'atmosphère et sont source d'une pollution photochimique locale. Enfin, pour compléter l'étude du devenir du CLP, son spectre UV est réalisé en phase gazeuse et sa constante de photolyse est déterminée à 1,8 10-5 s-1, ce qui implique une durée de vie de 16 heures vis-à-vis de la photolyse en phase gazThis thesis establishes the mechanism of heterogeneous degradation of chlorpyrifos (CLP) towards OH-radicals and ozone for CLP on quartz plaques and towards ozone for various contaminations of sand with CLP. The kinetic constants of the heterogeneous degradation are determined in a photo-chemical reactor coupled with a GC/MS. The chlorpyriphos-oxon (CLPO) and the trichloropyridinol (TCP) are the degradation products in the heterogeneous phase for different oxidizer and medium. The heterogeneous reactivity of CLPO towards ozone and OH-radicals are also studied. The results show that the OH-radicals constitute the main pathway of heterogeneous degradation of the CLP and that the CLPO is more persistent than the CLP. The CLPO can be transported far from its point of application. The heterogeneous ozonolysis of the CLP on sand shows that the kinetics are dependent of the contamination in CLP with an exponential behavior.The mechanism established from the analysis of products detected in the condensed phase plans the formation of small organophosphate molecules transferred in the gas phase. We studied the reactivity of two volatile organophosphate molecules the O,O,O-triethylphosphate (TEP) and the O,O-diethylethylphosphonate (DEEP) towards OH-radicals and towards the atomic chlorine in gas phase as a function of the temperature. The TEP and the DEEP present rate constants above 10-10 cm3.molecule-1.s-1. These molecules thus quickly degrade in the atmosphere and are source of a local photochemical pollution.Finally, to complete the degradation pattern of the CLP, its gas phase UV spectra is measured and its constant of photolysis is determined to 1,8 10-5 s-1, involving a photolysis life time of around 16 hours
48
Auclair-Desrotour, Pierre. "Dissipation des marées thermiques atmosphériques dans les super-Terres". Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEO015/document.
Testo completoAbstract (sommario):
Cette thèse traite de la modélisation des marées fluides des planètes telluriques du système solaire et des systèmes exoplanétaires.En premier lieu, nous examinons la réponse de marée des couches atmosphériques, soumises au potentiel de marée gravifique et au forçage thermique de l’étoile hôte du système. Nous proposons un nouveau modèle global prenant en compte les processus dissipatifs avec un refroidissement newtonien, modèle à partir duquel nous traitons la dynamique des ondes de marées engendrées par ces forçages, et quantifions leur dissipation, le nombre de Love et le couple de marée exercé sur la couche atmosphérique en fonction de la fréquence de forçage. Ceci nous permet d'étudier l'ensemble des configurations possibles depuis les planètes au voisinage de la synchronisation telles que Vénus jusqu'aux rotateurs rapides tels que la Terre.En second lieu, nous développons une approche similaire pour les océans de planètes de type terrestre, où la friction visqueuse effective de la topographie est prise en compte, à partir de laquelle nous quantifions la réponse de marée d’un océan global potentiellement profond et sa dépendance à la fréquence d’excitation. Dans ce cadre, et ce grâce à des modèles locaux, nous caractérisons de manière détaillée les propriétés des spectres en fréquence de la dissipation engendrée par les ondes de marées au sein des couches fluides planétaires (et stellaires) en fonction des paramètres structurels et dynamiques de ces dernières (rotation, stratification, viscosité et diffusivité thermique)This thesis deals with the modeling of fluid tides in terrestrial planets of the Solar system and exoplanetary systems.First, we examine the tidal response of atmospheric layers, submitted to the tidal gravitational potential and the thermal forcing of the host star of the system. We propose a new global model taking into account dissipative processes with a Newtonian cooling, model that we use to treat the dynamics of tidal waves generated by these forcings, and to quantify their dissipation, the Love number and the tidal torque exerted on the atmospheric layer as a function of the forcing frequency. This allows us to study possible configurations from planets close to synchronization such as Venus to rapid rotators such as the Earth.Second, we develop a similar approach for the oceans of terrestrial planets where the action of topography is taken into account thanks to an effective viscous friction. From this modeling, we quantify the tidal response of a potentially deep global ocean and its dependence of the tidal frequency. In this framework, and by using local models, we characterize in detail the properties of the frequency spectra of dissipation generated by tidal waves within fluid planetary (and stellar) layers as functions of the structural and dynamical parameters of these latters (rotation, stratification, viscosity and thermal diffusivity)
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Rappucci, Gina. "Tidal Cycle Effects on the Occurrence of the Florida Manatee (Trichechus manatus latirostris) at the Port Everglades Power Plant". NSUWorks, 2009. http://nsuworks.nova.edu/occ_stuetd/228.
Testo completoAbstract (sommario):
The seasonal distribution of the Florida manatee (Trichechus manatus latirostris) is influenced predominantly by feeding locations in the summer and proximity to warm-water refuges during colder months. Due to their limited ability to tolerate cold water, when water temperatures drop below 20°C manatees congregate around natural and artificial warm-water refuges, such as warm-water springs or power plant outfalls. Distribution may further be influenced by the tidal cycle through its impact on manatee movement and foraging. Although the importance of tide on manatee distribution and habitat selection has been acknowledged, it has yet to be studied quantitatively in respect to the manatee population in southeast Florida. The purpose of this study was to examine the effect of the tidal cycle on manatee occurrence at the Florida Power & Light (FPL) Port Everglades Power Plant.
Walking surveys were conducted in Port Everglades during manatee season, November 15 – March 31, between 2004 and 2008. During the surveys, the number of manatees in four established locations was noted and the animals categorized based on size as either calf, juvenile, or adult. Water temperature data were also collected at four permanent sample locations.
Because many surveys yielded zero manatees observed, data were analyzed using the zero-inflated negative binomial model. Although the manatees at the Port Everglades Power Plant must forage away from the warm-water refuge, my findings show no correlation between tidal state and total manatee occurrence at the FPL Port Everglades Power Plant. The results do, however, suggest that the probability of observing a cow/calf pair is greater during high tide when compared to low and mid-tides (P < 0.05). Total manatee occurrence and the presence of cow/calf pairs were both significantly correlated with water temperature (P < 0.05).
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Foster, Kristi A. "Field Ecology Patterns of High Latitude Coral Communities". NSUWorks, 2011. http://nsuworks.nova.edu/occ_stuetd/82.
Testo completoAbstract (sommario):
Some climate models predict that, within the next 30-50 years, sea surface temperatures (SSTs) will frequently exceed the current thermal tolerance of corals (Fitt et al. 2001; Hughes et al. 2003; Hoegh-Guldberg et al. 2007). A potential consequence is that mass coral bleaching may take place (i) during warm El Niño-Southern Oscillation (ENSO) events which are predicted to occur in some regions more frequently than the current 3-7 year periodicity (Hoegh-Guldberg 1999; Sheppard 2003) or (ii) perhaps as often as annually or biannually if corals and their symbionts are unable to acclimate to the higher SSTs (Donner et al. 2005, 2007). Global data also indicate an upward trend toward increasing frequencies, intensities, and durations of tropical hurricanes and cyclones (Emanual 2005; Webster et al. 2005). As coral communities have been shown to require at least 10-30 years to recover after a major disturbance (e.g. Connell 1997; Ninio et al. 2000; Bruno & Selig 2007; Burt et al. 2008), it is possible that future coral communities may be in a constant state of recovery, with regeneration times exceeding the periods between disturbances. Life history traits (e.g. reproduction, recruitment, growth and mortality) vary among species of hard corals; thus, gradients in community structures may have a strong influence on susceptibilities to disturbance and rates of recovery (Connell 1997; Ninio & Meekan 2002). Taxa which are more susceptible to bleaching and mechanical disturbance (e.g. tabular and branching acroporids and pocilloporids) may experience continual changes in population structure due to persistent cycles of regeneration or local extirpation, while the more resistant taxa (e.g. massive poritids and faviids) may display relatively stable population structures (Woodley et al. 1981; Hughes & Connell 1999; Baird & Hughes 2000; Marshall & Baird 2000; Loya et al. 2001; McClanahan & Maina 2003). Determining whether resistant coral taxa have predictable responses to disturbances, with consistent patterns over wide spatial scales, may improve predictions for the future affects of climate change and the composition of reefs (Done 1999; Hoegh-Guldberg 1999; McClanahan et al. 2004).
The work presented in this dissertation describes the spatial and temporal patterns in community structures for high latitude coral assemblages that have experienced the types of natural disturbances which are predicted to occur in tropical reef systems with increasing frequency as a result of climate change. The primary area of focus is the southeastern Arabian Gulf, where the coral communities are exposed to natural conditions that exceed threshold limits of corals elsewhere in the world, with annual temperature ranges between 14-36°C (Kinzie 1973; Shinn 1976) and salinities above 40 ppt. Two additional regions are included in this study for comparisons of high latitude coral community structures. The northwestern Gulf of Oman is adjacent to the southeastern Arabian Gulf (i.e. the two bodies of water are connected by the Strait of Hormuz); however, the environmental conditions are milder in the Gulf of Oman such that the number of coral taxa therein is threefold that found in the southeastern Arabian Gulf (i.e. 107 coral species in the Gulf of Oman compared to 34 species in this region of the Arabian Gulf (Riegl 1999; Coles 2003; Rezai et al. 2004)). Broward County, Florida is geographically remote from the Gulfs and, therefore, serves as a benchmark for testing whether consistent patterns in community structures exist despite different climatic and anthropogenic influences.
The coral communities within the southeastern Arabian Gulf, the northwestern Gulf of Oman, and Broward County, Florida have been exposed to recurrent elevated sea surface temperature (SST) anomalies, sequential cyclone and red tide disturbances, and frequent hurricanes and tropical storms, respectively. These disturbances and other impacts (e.g. bleaching episodes, disease outbreaks, anthropogenic stresses) have affected the more susceptible acroporids and pocilloporids, resulting in significant losses of coral cover by these families and shifts towards massive corals as the dominant taxa. During the post-disturbance scarcity or absence of branching and tabular corals, the resistant massive taxa have become the crux of the essential hard coral habitat for fish, invertebrates and other marine organisms.
Because recovery to pre-disturbance community structures may take decades or may not occur at all, it is vital that scientists and resource managers have a better understanding of the spatial and temporal ecology patterns of the corals that survive and fill in the functional gaps that are created by such disturbances. To aid in this understanding, this dissertation presents spatial and temporal patterns for the coral assemblages which have developed after the respective disturbances. Spatial ecology patterns are analyzed using graphical descriptions (e.g. taxa inventories, area cover, densities, size frequency distributions), univariate techniques (e.g. diversity indices), distributional techniques (e.g. k-dominance curves) and multivariate techniques (e.g. hierarchical clustering, multidimensional scaling). Temporal comparisons at monitoring sites within the southeastern Arabian Gulf and northwestern Gulf of Oman describe the coral population dynamics and are used to create size class transition models that project future population structures of massive corals in the recovering habitats.