Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2005. / Land degradation in Lesotho is undermining the finite resource on which people depend for survival. Use of satellite imagery has been recommended for monitoring land degradation because remotely sensed data enable monitoring of large areas at more frequent intervals than intensive ground based research. Various techniques have been developed for land cover change detection. In the present study, vegetation changes were identified by image differencing, which involved finding the difference between the earlier date NDVI image and the later date image. NDVI images are among products that are generated from the NOAA AVHRR sensor to provide information about the quantity of biomass on the earth’s surface. The resulting NDVI change data showed land areas that had experienced vegetation loss, which were identified as potentially degraded. The change data were combined with other data sets to determine how potentially degraded areas were influenced by different environmental variables and population pressure. These data sets included land cover, ecological zones, elevation, soil and human and livestock populations. By integrating NDVI data with ancillary data, land degradation was attributed to both demographic pressure and biophysical factors. Widespread degradation was detected on the arable parts of the Lowlands where cultivation was intensive and human settlements were extensive. Signs of grassland depletion and forest decline were also evident and were attributed to population expansion, overgrazing and indiscriminate cutting of trees and shrubs for firewood. Extensive biomass decline was also associated more with soils in the lowlands derived from sedimentary rocks than soils of basalt origin that occur mostly in the highlands. Significant degradation was evident on gentle slopes where land uses such as cultivation and expansion of settlements were identified as the main causes of the degradation. There was evidence of greater vegetation depletion on north and east-facing slopes than on other slopes. The depletion was attributed to the fragility of ecosystems resulting from intense solar radiation. The study demonstrated that NOAA AVHRR NDVI images could be used effectively for detecting land cover changes in Lesotho. However, future research could focus on obtaining and using high resolution data for detailed analysis of factors driving land degradation.

This master thesis is dealing with a system for receiving meteorological images from satellites placed on lower orbit. Furthermore it gives basic information about satellites NOAA, METOP and FY. It also includes derivations of equations, that define minimal requirements for receiving antenna and LNA. From reached parametres, energetic balance for connection of the satellite and Earth is calculated. The main part of the master thesis is designing of low-noise amplifier for L band. LNA is implemented on the substrate FR4 and Arlon DiClad 870, circuit is designed with elements of parametres, which are spread out or concentrated. The last part of the thesis describes design of antenna for reception of meteorological images.

Commercial pelagic longline fishers within the U.S. Atlantic, Gulf of Mexico, and Caribbean are required to report all fishing interactions per each gear deployment to NOAA’s Vessel Logbook Program of the Southeast Fisheries Science Center to quantify bycatch, increase conservation efforts, and avoid jeopardizing the existence of vulnerable species listed under the Endangered Species Act (ESA). To provide additional accuracy, the Pelagic Observer Program (POP) of the SEFSC deploys professionally trained observers on longline vessels to produce a statistically reliable subset of longline fisheries data. A comparison of self-reported (“unobserved”) datasets versus observer-collected (“observed”) datasets showed a general consistency for most target species but non-reporting or under-reporting for a number of bycatch species and “lesser-valued” target species. These discrepancies between catch compositions and abundancies regarding targeted species, species of bycatch concern, and species of minimum economic value can provide insight into increased fisheries regulations, stricter requirements, or additional observer coverage.

The political history of U.S. commercial remote sensing began in 1984 when the U.S. government first attempted to commercialize its civil earth observation satellite system " Landsat. Since then, the high technology of earth imaging satellite systems has generated intense debates and policy conflicts, primarily centered on U.S. government concerns over the national security and foreign policy implications of high-resolution commercial satellite systems. Conversely, proponents of commercial observation satellites have urged U.S. policymakers to recognize the scientific and socio-economic utility of commercial remote sensing and thus craft and implement regulatory regimes that allow for a greater degree of information openness and transparency in using earth observation satellite imagery. This dissertation traces and analyzes that tumultuous political history and examines the policy issues and social construction of commercial remote sensing to determine the role of knowledge in the effective crafting and execution of commercial remote sensing laws and policies. Although individual and organizational perspectives, interests, missions, and cultures play a significant role in the social construction of commercial observation satellite systems and programs, the problem of insufficient knowledge of the myriad dimensions and complex nature of commercial remote sensing is a little studied but important component of this social construction process. Knowledge gaps concerning commercial remote sensing extend to various dimensions of the subject matter, such as the global, economic, technical, and legal/policy aspects. Numerous examples of knowledge voids are examined to suggest a connection between deficient knowledge and divergent policy perceptions as they relate to commercial remote sensing. Relevant knowledge voids are then structurally categorized to demonstrate the vastness and complexity of commercial remote sensing policy issues and to offer recommendations on how to fill such knowledge gaps to effect increased collaboration between the US government and the U.S. commercial remote sensing industry. Finally, the dissertation offers suggestions for future STS studies on policy issues, particularly those that focus on the global dimensions of commercial remote sensing or on applying the knowledge gap concept advanced by this dissertation to other areas of science and technology policymaking. / Ph. D.

Consideramos a região costeira e oceânica abrangida neste estudo como um sistema de grande escala, que se extende dês Cabo Frio(RJ) (lat. 23º00S) até Cananéia(SP) (lat. 25º00S) Nas análises de uma série temporal dos dados de temperatura da superfície do mar obtido por sensoriamento remoto pelo satélite NOAA/4 foram observadas diferenças no tempo de ocorrência das máximas e mínimas temperatura médias mensais em relação à estação costeira de Cananéia(SP). Essa diferença foi de dois meses para o máximo e um mês para o mínimo. Para o componente anual de variação de temperatura observamos áreas de maiores amplitudes de temperatura da superfície do mar (Cabo Frio-RJ. Influência do fenômeno de ressurgência e Cananéia-SP, influência da corrente das Malvinas) e de menores amplitudes nas áreas costeira e oceânica (entre Ubatuba-SP e Santos_SP, indicando uma área termicamente mais estável)> Para os componentes com período de 06, 04 e 03 meses as maiores amplitudes ocorrem nas mesmas áreas já citadas, com exceção da região oceânica (lat. 25º30S e long. 042º00W) para o componente de 06 meses. A circulação na região adjacentes à Ilha Grande-RJ (lat. 23º15S), cuja amostragem foi realizada em escala média, foi descrita através de diagramas vetoriais progressivos (determinamos um circulação de fundo do sentido horário na Baía de Ilha Grande-RJ, em junhop de 1976). As flutuações de curto período foram determinadas através da análise de - autocorrelação obtendo-se os seguintes resultados: na parte oeste da baía, flutuações de ordem de 35 a 70 min; na parte leste da baía, flutuações da ordem de 50 a 70 min e flutuações da ordem de 3h 30min e 5h e 24min, para as profundidades - médias e próximos ao fundo, respectivamente. O caráter turbulento dos movimentos observados foi determinado através do Número de Richardson. As propriedades dispersivas nessa região foram simuladas experimentalmente, sendo os coeficientes de difusão (k - 3.5 x 10³ e 9.0 x 10³ cm².s -¹ ) determinados por técnica. fluorométricas com o uso da Rhodamina-B como traçador. / The oceanic and coastal área from Cabo Frio (RJ) (23º00S lat.) Cananéia (SP) (25°00\'S lat.) was considered large scale systems. Through time series analysis of the NOAA-4 sea surface temperature (SST) data, time differences in the occurrence of maximum and minimun mean monthly SST were observed and showed the maximum surface Walter temperature to lag coastal land station (Cananéia)by 2 months and the minimum by 1 months. For annual component of SST maximum amplirtudes were observed at Cabo Frio (upwelling Influences) and Cananéia (Malvinas Current Influences) and minimum amplitudes at coastal and oceanic area between Ubatuba(SP) and Santos (SP)(more thermal stable area). For the 6. 4 and Santos 3 month components the maximum amplitudes occurred at the areas mentioned previously, with exception to the oceanic area(25º30\'S lat. And 042º00w long.) for 6 month component. A mesoscale study was also made pn the Ilha Grande(RJ) area(23º15S lat.). The circulation was described through progressive vector diagrams (PVDs) (clockwise bottom circulatin was determined in June. 1976). Evaluation of the short period fluctuation was determined through autocorrelation analysis: West part of bay (35 to 70 min). East part of bay (50 to 70 min mean depth and 3h30 min to 5h24 min bottom depth. Studies of turbulence were made through the use of the Richardson Number. Two disperation (e.g. k + 3,5 x 10³ cm² sec-¹ and 9 x 10³ cm² sec-¹) studies were Rhodamine B exporiments.

Consideramos a região costeira e oceânica abrangida neste estudo como um sistema de grande escala, que se extende dês Cabo Frio(RJ) (lat. 23º00S) até Cananéia(SP) (lat. 25º00S) Nas análises de uma série temporal dos dados de temperatura da superfície do mar obtido por sensoriamento remoto pelo satélite NOAA/4 foram observadas diferenças no tempo de ocorrência das máximas e mínimas temperatura médias mensais em relação à estação costeira de Cananéia(SP). Essa diferença foi de dois meses para o máximo e um mês para o mínimo. Para o componente anual de variação de temperatura observamos áreas de maiores amplitudes de temperatura da superfície do mar (Cabo Frio-RJ. Influência do fenômeno de ressurgência e Cananéia-SP, influência da corrente das Malvinas) e de menores amplitudes nas áreas costeira e oceânica (entre Ubatuba-SP e Santos_SP, indicando uma área termicamente mais estável)> Para os componentes com período de 06, 04 e 03 meses as maiores amplitudes ocorrem nas mesmas áreas já citadas, com exceção da região oceânica (lat. 25º30S e long. 042º00W) para o componente de 06 meses. A circulação na região adjacentes à Ilha Grande-RJ (lat. 23º15S), cuja amostragem foi realizada em escala média, foi descrita através de diagramas vetoriais progressivos (determinamos um circulação de fundo do sentido horário na Baía de Ilha Grande-RJ, em junhop de 1976). As flutuações de curto período foram determinadas através da análise de - autocorrelação obtendo-se os seguintes resultados: na parte oeste da baía, flutuações de ordem de 35 a 70 min; na parte leste da baía, flutuações da ordem de 50 a 70 min e flutuações da ordem de 3h 30min e 5h e 24min, para as profundidades - médias e próximos ao fundo, respectivamente. O caráter turbulento dos movimentos observados foi determinado através do Número de Richardson. As propriedades dispersivas nessa região foram simuladas experimentalmente, sendo os coeficientes de difusão (k - 3.5 x 10³ e 9.0 x 10³ cm².s -¹ ) determinados por técnica. fluorométricas com o uso da Rhodamina-B como traçador. / The oceanic and coastal área from Cabo Frio (RJ) (23º00S lat.) Cananéia (SP) (25°00\'S lat.) was considered large scale systems. Through time series analysis of the NOAA-4 sea surface temperature (SST) data, time differences in the occurrence of maximum and minimun mean monthly SST were observed and showed the maximum surface Walter temperature to lag coastal land station (Cananéia)by 2 months and the minimum by 1 months. For annual component of SST maximum amplirtudes were observed at Cabo Frio (upwelling Influences) and Cananéia (Malvinas Current Influences) and minimum amplitudes at coastal and oceanic area between Ubatuba(SP) and Santos (SP)(more thermal stable area). For the 6. 4 and Santos 3 month components the maximum amplitudes occurred at the areas mentioned previously, with exception to the oceanic area(25º30\'S lat. And 042º00w long.) for 6 month component. A mesoscale study was also made pn the Ilha Grande(RJ) area(23º15S lat.). The circulation was described through progressive vector diagrams (PVDs) (clockwise bottom circulatin was determined in June. 1976). Evaluation of the short period fluctuation was determined through autocorrelation analysis: West part of bay (35 to 70 min). East part of bay (50 to 70 min mean depth and 3h30 min to 5h24 min bottom depth. Studies of turbulence were made through the use of the Richardson Number. Two disperation (e.g. k + 3,5 x 10³ cm² sec-¹ and 9 x 10³ cm² sec-¹) studies were Rhodamine B exporiments.

In order to understand the dynamics of desertification after the 1980s droughts, the trends and changes of photosynthetically active fraction of the vegetation cover of the semi-arid region of West Africa have been analyzed across three ecoclimatic entities. This study focuses on six countries (Senegal, Mauritania, Mali, Burkina-Faso, Niger and Benin) that reflect quite well the human and environmental context of semi-arid regions. The main objective of this thesis is to check in the before-mentioned biophysical and human context, if the state of the vegetation improves because of more favourable rainfall conditions, or if, conversely, the long environmental deterioration during recent decades has a healthy dose of irreversibility for several years. The process of investigation proceeds in three stages defined by geographical scales and a geoclimatic gradient. At the regional level, we compared vegetation productivity data from 1982-1999 time series of NOAA-AVHRR NDVI data to rainfall data. We analyzed data from 315 rain gauges distributed across five countries (Senegal, Mauritania, Mali, Burkina-Faso and Niger) with annual average isohyets ranging from 100 to 900 mm. For trends analysis, we used the ratio of the integrated vegetation index (iNDVI) during the crop-growth period (June to October) to the May to October sum of rainfall (RR). This ratio (iNDVI/RR), a proxy of the Rain Use Efficiency, is widely used by ecologists as an indicator for detecting desertification processes. Overall, our results show a significant increase of the net primary production as a response of post-drought rainfall increase. However, the trends of iNDVI/RR ratio suggest that most of the studied stations (54%) in sahelian and sahelo-sudanese belts were stable and 31.4% showed strong to very strong negative change in iNDVI/RR ratio, while 13.3% of the stations showed a moderate decrease and only 1.3% showed a positive trend. At the country level, similar trends were recorded throughout 128 stations in Burkina Faso located between the 500 mm and 1100 mm isohyets. In fact, more than half the studied stations showed a stability of iNDVI/RR ratio. However, 39.8% of them show a negative trend from low to high, while only 2.4% of them show a slight positive trend. In addition, a comparison with more detailed local case studies confirmed these observed trends. However, the obtained results for wetter stations in the southern part of the country should be taken with precaution, as the relationship between NDVI and rainfall tends to weaken when annual rainfall is higher than 1000 mm. Overall, the negative trends highlight a gradual decline in plant productivity. These results recorded in 44.7% of the analyzed stations may reflect ongoing desertification processes in the sahelian and sahelo-sudanian zones over the past two decades. At the local level, a structural characterization of woody units in three bioclimatic regions of the sudanian zone (900 mm 1200 mm) in the north of Benin was conducted to assess their degradation status. We recorded the structural characteristics of stands (basal area, density), species diversity as well as disturbances type and intensity. Multivariate analysis revealed a gradient of productivity between the three regions: there was a high diversity of woody stands in the south-sudanian sector, while the north-sudanian and sudano-sahelian sectors were dominated by savannas and shrub, which had low productivity. The productivity gradient is influenced by a disturbance gradient suggesting that the decline in productivity is stronger from south-sudanian to the sudano-sahelian region. In addition, the spatial component of the observable changes in vegetation cover has been mapped by remote sensing in a restricted area of the sudanian zone in northern Benin with SPOT-XS data over the period 1986-2005. Over the past two decades, 19.6% of the woody stands have completely disappeared; 12.9% of this extinction of woody stands was due to deforestation, and 13.9 % due to degradation processes. In contrast to these trends, 21.8% of the study area were stable, while less than a third (31.7%) of the area were experiencing woody recovery (reforestation). The analysis also reveals significant disparities in the rates of change of the identified land use class units. These variations are more pronounced for the woody units and agricultural land than in villages. These results suggest that land cover degradation throughout the study area is primarily due to anthropogenic factors (livestock and agricultural expansion, logging, breeding). In fact, this area is a preferred destination for agricultural migrants fleeing the unpredictable climatic conditions of the drier semi-arid areas. Overall, our results highlight the rapid decline of vegetation resources, challenging assumptions that the impact of ongoing desertification processes is mixed, outside of the arid and semi-arid regions of West Africa. The developed framework is easily reproducible and allows the implementation of a reliable diagnosis on the state of the vegetation cover from accessible and inexpensive data. Its implementation should facilitate the development of managerial techniques for better assistance to the poor, especially vulnerable to the gradual degradation of their environment.

The study of solar radiation is a key process for the exploitation of solar energy systems. In most cases, however, the availability of information is insufficient and not up-to-date. In addition, the interpolation of ground-level measurement stations data does not allow the observation of microclimatic aspects of solar radiation (Zelenka at al., 1999). Therefore, a statistical model and NOAA-AVHRR satellite images were selected for the determination of solar radiation maps for the entire Iberian Peninsula. The statistical methodology based on Diabate et al. (1989) and Flores (2002) assures the accuracy of the process and the NOAA-AVHRR images provide a fine high resolution of 1 km2, which is needed because of the complexity of the area of study. The period of study covers five years (1998-2002), which assures the study of the year-on-year variation of solar radiation. The statistical model was calibrated with data from 21 ground-level measurement stations all around the Iberian Peninsula. These data were filtered with the aim of eliminating all erroneous registers, which a crucial subject in the method. The satellite images were geometrically calibrated and corrected. Furthermore, a methodology for the detection of clouds was applied in order to obtain the surface albedo (Laine et al., 1999). The evaluation of results, with 7 independient ground-level measurement stations, leads to a MBE of −3.8% and a RMSE of 24.4% for the daily data and a MBE of −1.1% and a RMSE of 15.9% for the hourly data. Maps of hourly and daily solar radiation for the years of study and the average tendency were determined. The Iberian Peninsula receives a mínimum of 4.2 MJm−2 d−1 and a maximum of 26 MJm−2 d−1 of dailly solar radiation, whith a mean of 15.1 MJm−2 d−1. The year-to-year variability of solar radiation ranges between 14.9 MJm−2 d−1 for year 2002 to 17.3 MJm−2 d−1 for year 2000. The results clearly show the usefulness of this work when obtaining solar radiation maps with a high temporal (hourly and daily maps) and spatial resolution (1 km2). / El estudio de la radiación solar es un proceso clave para el aprovechamiento de la energía solar. En la mayoría de los casos, sin embargo, la disponibilidad de información es insuficiente y desactualizada. Adicionalmente, la interpolación de superficie obtenida a partir de estaciones de medición en superficie no permite la observación de los aspectos microclimáticos de la radiación solar (Zelenka et al., 1999). Por esto, se ha elegido un modelo estadístico e imágenes del satélite NOAA-AVHRR para la determinación de mapas de radiación solar para toda la Península Ibérica. El método estadístico basado en Diabaté et al. (1989) y Flores (2002) asegura la exactitud del proceso y las imágenes NOAA-AVHRR una alta resolución espacial del orden de 1 km2, lo cual es necesario dada la complejidad del área de estudio. El período de estudio es de 5 años (1998-2002), lo que permite estudiar la variación interanual de la radiación solar. El modelo estadístico fue calibrado con 21 estaciones de medición en superficie distribuidas en toda la superficie de España. Los datos de las estaciones de medición son acuciosamente filtrados con el propósito de eliminar todos los registros erróneos, aspecto crucial del método. Las imágenes son calibradas y corregidas geométricamente, además se les realiza un proceso de detección de nubes con el fin de obtener el albedo superficial (Laine et al., 1999). La evaluación de los resultados, con datos de 7 estaciones de medición en superficie independientes, permite obtener un MBE de −3.8% y un RMSE de 24.2% para los dato diarios y un MBE de −1.1% y un RMSE de 15.9% para los datos horarios. Se obtienen mapas de radiación solar horarios puntuales y diarios para todos los años del período de estudio, además se determina la tendencia media de los mismos. Los resultados muestran que la Península Ibérica recibe un mínimo de 4.2 MJm−2 d−1 y un máximo de 26 MJm−2 d−1, con una radiación solar media de 15.1 MJm−2 d−1. La variabilidad interanual de la radiación solar queda expresada con valores que van desde 14.9 MJm−2 d−1 para el año 2002 hasta 17.3 MJm−2 d−1 para el año 2000. Los resultados demuestran claramente la utilidad del trabajo en la obtención de mapas de radiación solar horarios y diarios con una alta resolución espacial (1 km2).

The L5 signal of the Global Positioning System (GPS) is becoming available on an increasing number of Block IIF satellites. As the third civilian signal, L5 is superior in signal design to the L1 C/A and L2C civilian signals. This new signal has been marked healthy for use on selected satellites since 2010, yet the hardware capable of tracking the L5 signal is still in the early stages of development. This work investigates the characteristics of the new signal and the quality of data produced by L5-tracking receivers. Commonly used receiver models chosen for this study are the Leica GRX1200+GNSS, the Trimble NetR8, and the Javad Delta TRE-G3TH. The metrics used in this analysis to assess the quality of data produced by these receivers are signal strength, receiver phase noise, receiver code noise, and multipath. The data used in these analyses were obtained from the International GNSS Service for the days of the year 275 to 281 in 2011. Metrics averaged over the GPS week 1656 provide a good indication of the overall performance of the receivers. / text

The Oil Pollution Act of 1990 requires the development of Regional and Area Contingency Plans. For more than 20 years, the State of Florida, under both the Department of Environmental Protection and the Florida Fish and Wildlife Commission, has worked closely with the U.S. Coast Guard and the National Oceanic and Atmospheric Administration to develop these plans for coastal and marine oil spill response. Current plans, developed with local, state and federal stakeholder input, use geographic information systems (GIS) data such as location and extent of sensitive ecological, wildlife, and human-use features (termed Environmental Sensitivity Index data), pre-defined protection priorities, and spatially explicit protection strategies to support decision-making by responders (termed Geographic Response Plans). However, they are long overdue for improvements that incorporate modern oceanographic modeling techniques and integrated data from coastal ocean observing systems. Better understanding of circulation in nearshore and estuarine waters, at a scale consistent with other spatial data, is especially lacking in Area Contingency Plans. This paper identifies the gaps in readily available information on the circulation-driven causes and effects missing in current oil spill contingency planning and describes a sample methodology whereby multiple coastal and ocean spatial science disciplines are used to answer questions that no single, non-integrated discipline can answer by itself. A path forward for further integration and development of more comprehensive plans to better support coastal protection in Florida is proposed. The advances made here are applicable to other coastal regions of the world.