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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Análise da influência gravitacional lunar sobre os complexos convectivos de Mesoescala na região Nordeste brasileira / Analysis of the lunar gravitational influence on the Mesoscale convective complexes in the Northeast brazilian region

Gonçalves, Anderson 18 March 2016 (has links)
This study verified if the behavior since formation to dissipation on a Mesoscale Convective Complex (MCC) is somehow related to the sea level rising caused by ocean tide. The objective of this study is to find a possible link between ocean height variation and the MCC event. The ocean tide data were obtained from the Banco Nacional de Dados Oceanográficos (BNDO) between January 2005 and December 2009. The MCC event data in this period were collected in previous researches in UFAL Sinoptics Laboratory which add up the total of 41 cases. When relating the ocean tide forecast data with the MCC, a significant relationship was observed. A significant variation in sea surface temperature related with MCC was detected. There was an evident relationship between seasonality with tide behavior and lunar phase and duration of MCC. The major occurrence of the MCC are in Autumn with 63% of the cases. There are no records of a Winter MCC. The MCC events reached its maximum growth in 63% of cases in the flood tide. The dissipation occurred in 56% of the tidal flow. A probable association between the sea temperature variation with depth of 60 meters with the occurrence of MCC event was verified. A more detailed study of the temperature variations is needed to confirm the relationship. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este estudo verificou se o comportamento desde formação à dissipação dos Complexos Convectivos de Mesoescala (CCM) está de alguma forma relacionado a elevação do nível do mar causada pela maré oceânica. O objetivo deste estudo é encontrar uma possível relação entre a variação da altura do oceano e o evento CCM. Foram utilizados os dados de previsão de maré oceânica, obtidos no Banco Nacional de Dados Oceanográficos (BNDO) entre Janeiro de 2005 e Dezembro de 2009. Os dados de eventos CCM no período de estudo, foram adquiridos em trabalhos anteriores do Laboratório de Sinótica da UFAL e somam o total de 41 casos. Ao cruzar os dados da previsão de maré oceânica com os de CCM, observou-se relações relevantes para o estudo. Foram observadas algumas situações de variação significativa na temperatura da superfície do mar com o evento CCM. Ficaram evidentes as relações de sazonalidade com comportamento da maré e fase lunar e duração do CCM. A maior ocorrência dos casos 63% é no Outono. Não existem ocorrências no Inverno. Os eventos de CCM atingiram seu máximo desenvolvimento em 63% dos casos na enchente da maré. A dissipação ocorreu em 56% na vazão da maré. Foi verificada uma possível relação entre a variação de temperatura do mar na profundidade de 60 metros com a ocorrência do evento CCM. Um estudo mais detalhado sobre as variações de temperatura se faz necessário para confirmar a relação.
2

Patterns in the larval vertical distribution of marine benthic invertebrates in a shallow coastal embayment

Lloyd, Michelle 20 September 2011 (has links)
Processes during the meroplanktonic phase regulate population dynamics for many marine benthic invertebrates. I examined changes in vertical distribution of different meroplanktonic larvae in a coastal embayment during a stable period, at high temporal frequencies and spatial resolutions. Plankton samples were collected at 6 depths (3, 6, 9, 12, 18, 24 m) using a pump, every 2-h over a 36- and a 25-h period, during a spring and neap tide, respectively, concurrently with measures of temperature, salinity, fluorescence and current velocity. For 10 gastropod taxa, larval vertical distribution was mostly related to the thermal structure of the water column. Each of 7 taxonomic groups was found either exclusively near the surface, associated with the fluorescence maximum, or showed diel changes in distribution. These larvae that occupy different depths in the water column exhibit different dispersal potentials. / Biogeographical data contained in this thesis will be submitted to the Oceanographic Biogeographic Information System (OBIS) and may be accessed on-line at http://www.iobis.org
3

Environmental Factors Affecting Loggerhead Sea Turtle (Caretta caretta) Nesting, Hatching, and Incubation Patterns in Broward County, Florida

Best, Zoey Ellen 28 April 2017 (has links)
Reproductive success in loggerhead (Caretta caretta) sea turtles is strongly dependent on the effective placement and internal conditions of their nests. Embryos rely on optimal incubation conditions for proper development and growth, which determines how many hatchlings will emerge from the nest. The internal microclimate of each nest is delicately balanced and can be easily influenced by external environmental conditions. This study was designed to examine several environmental variables and determine their effects on sea turtle nesting numbers, hatching success, and incubation conditions in Broward County Florida. Over a span of 25 years (1991-2015), the Broward County Sea Turtle Conservation Program has collected data on each sea turtle nest laid in Broward County. This data was analyzed and plotted to visualize nesting and hatching trends, and regressions were fitted to make comparisons to historic air temperature, sea surface temperature, precipitation, and lunar illumination data. These regressions were tested for significance, and each environmental variable was found to have varying levels of impact on sea turtle nesting and hatching behavior. Of the environmental variables considered in this study, analyses suggest that sea turtles are most responsive to temperature, with sea surface temperature serving as the best proxy for predicting nesting behaviors. Air temperature over the incubation period was found to be the best indicator for hatch success percentage. Air temperature, sea surface temperature, and precipitation averages all significantly affected the length of the incubation period. The regression models created in this study could be used to examine the interactions between climatic variables, and to indicate what impacts can be expected by these various environmental factors. This information could be used to estimate the future effects of climate change on sea turtle reproduction, and to predict general reproductive success and future population trends.

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