Ultraviolet (UV) radiation has several effects on human health as well as other biological and chemical systems. The radiation can be weighted with the erythemal action spectrum and then converted to the dimensionless UV Index, which is designed to indicate the detrimental 'sunburning power' of the radiation for public heath purposes. A global view of the erythemally weighted irradiance from the Ozone Monitoring Instrument (OMI) on board the Aura spacecraft has been available since July, 2004. However, ground-based validation and correction of the satellite data are still required. In this thesis, the erythemal dose rates at local solar noon taken from the satellite were compared to ground-based data measured by spectroradiometers or broadband radiometers in two different climate areas: the Tropics and midlatitudes. This seeks to redress the lack of data and satellite validation for the Tropics, and also allows comparison with previous work in midlatitudes. The validation results show that the satellite data overestimates the ground-based data by 9%-32% at the cleanest site, with a much higher discrepancy at polluted sites. Using a radiative transfer model confirmed that the positive bias in the satellite data was mainly caused by aerosol absorption that is not taken into account in the satellite retrieval algorithm. Therefore, two empirical methods were introduced in order to correct the OMI UV data for absorbing aerosols under clear sky conditions. These methods required aerosol optical depth and aerosol single scattering, or aerosol absorption optical depth, as input parameters. The methods improved the OMI UV data by up to 30% depending on site and input data source. For cloudy conditions aerosol data is usually not available either from ground-based or satellite-based measurements; however, the effect of cloud is usually far greater than that of aerosol, and some of the aerosol effect (scattering) is intrinsically included in the cloud correction. A further empirical model for cloudy conditions was derived to reduce bias of the OMI UV data with respect to ground-based data. The method only requires the OMI UV data as an input. The cloudy model reduced the bias by about 13%-30% depending on site, and gave similar results even when used with clear sky data. Since ground-based data is sparse, the final goal of the work was to produce a corrected map of UV index for the whole of Thailand, based only on data available from satellite, which gives full regional coverage. Issues with availability and quality of satellite data meant that the best results were achieved by using only the cloudy sky correction, for all conditions. The resulting daily noontime UV Index maps of Thailand were assessed against ground-based data for independent years. The corrected UV Index was within ±2 compared with ground-based data for all sites, compared to discrepancies of up to 4 UV Index for uncorrected data.

The field of wildlife rescue and rehabilitation continues to grow as human expansion increases the rate of deforestation in Latin America. Wild animals that are often rescued from becoming orphaned or injured are rehabilitated in captivity until considered suitable for release back into the wild. Sloths (Bradypus spp. and Choloepus spp.) are a common species admitted to rescue centers throughout Latin America due to their poor dispersal abilities and vulnerability to anthropogenic impacts. Post-release monitoring is fundamental in measuring the success of wildlife rescue programs, however, few studies have assessed the outcomes of releasing hand-reared sloths back into the wild. I studied the ecology of rehabilitated and relocated Hoffmann’s two-toed sloths (C. hoffmanni) in central Panamá. My objectives were to: (1) use a soft-release technique to quantify activity budgets of individuals prior to release in the wild, (2) analyze movement trajectories and estimate home range sizes, (3) assess habitat selection, and (4) determine survival rates and causes of mortality for rehabilitated and released two-toed sloths. Eleven two-toed sloths rescued from the wild were hand-reared in captivity for a mean total of 727  193 days (mean  SE value across all sloths) at the Pan-American Conservation Association facilities in Colón Province, Panamá. During 2019-2020, sloths were processed into 2 groups, radiomarked, placed in an outdoor 500 m2 soft-release enclosure for 3 months, and released in nearby Soberanía National Park. I conducted 580 hr of behavioral observations during soft-release to quantify activity budgets for 5 main activity states. A linear mixed model was used to compare two-toed sloth activity budgets in response to sex, age, season (i.e., dry vs. wet), session time (i.e., morning vs. evening) and month. Rehabilitated two-toed sloths spent 80.0% of their time resting, becoming active and more alert in the evening, exhibiting behavioral patterns similar to wild two-toed sloths (as ascertained from existing literature). I used homing to radiotrack two-toed sloths for 210 radio-days during which I used a paired analysis approach to measure tree height, crown height, height to crown base, diameter at breast height, abundance of lianas, canopy depth, and canopy closure at 118 used and random locations. Habitat selection was modeled using conditional logistic regression and movement trajectories were analyzed using ArcGIS. Rehabilitated two-toed sloths traveled shorter distances than wild two-toed sloths, traveling a mean linear distance of 82.3  21.6 m and a mean distance of 25.6  9.5 m between successive locations. Mean home range size for released two-toed sloths was 2.92  1.19 ha with females occupying larger areas than males. I did not find strong evidence of habitat selection; however, rehabilitated two-toed sloths chose trees with a smaller dbh than available. Habitats used by rehabilitated two-toed sloths closely resembled those used by wild two-toed sloths, selecting trees with dense crowns and 50% lianas. Monthly survival for rehabilitated two-toed sloths (0.72  0.14) was low relative to wild sloths, and monthly estimates for males (1.00  0.00) and females (0.44  0.22) did not differ (P  0.30). Eight mortalities were recorded with predation and natural causes being the main causes of mortality. My study provides information that can be useful in evaluating the costs and benefits of sloth rescue and rehabilitation programs throughout Latin America.

Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / Microfiche copy available in Archives and Lindgren. / Vita. / Bibliography: leaves 202-207. / Ph.D.

No description available.

Tropical regions have extensive networks of unpaved roads which can be the largest contributor of sediment loading within a watershed in terms of both sediment generation and delivery. A number of erosion and sediment prediction models have been developed for unpaved roads and applied across a wide range of locations. However, little work has been devoted to the comparison of these models or to their application in tropical environments. A 13 square kilometer mixed land use watershed in Eastern Brazil was used as a case study area for model application and comparison. Models chosen for evaluation were WEPP: Road, SEDMODL, and STJ-EROS. To determine the applicability of these models to the case study watershed, a classification system was developed to score road segments according to sediment production and delivery potential. Field observations provided data for the input parameters of the models as well as to identify which road segments appear to be high contributors of sediment within the watershed. These road segments were compared with the segments estimated by the models to have high sediment yields. The models identified less than 50% of those roads categorized by field observation as having high erosion potential. WEPP: Road matched more closely to the field observations than SEDMODL and STJ-EROS. To be useful tools for watershed management in the tropics, a unified method for calculating sediment delivery is needed as well as an adjustment to model input parameters so that they better reflect conditions in tropical watersheds. / Master of Science

Har, Tsoen Hei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 53-58). / Abstract also in Chinese. / List of Figures --- p.i / List of Tables --- p.iii / List of Acronyms --- p.iv / Chapter Chapter 1: --- Introduction --- p.1 / Chapter Chapter 2: --- Background / Chapter 2.1 --- Tropical Rainfall --- p.4 / Chapter 2.2 --- Aerosol-rainfall interactions --- p.7 / Chapter Chapter 3: --- Land-sea difference in tropical rainfall / Chapter 3.1 --- Introduction --- p.11 / Chapter 3.2 --- Method / Chapter 3.2.1 --- Linear Trend Analysis --- p.12 / Chapter 3.2.2 --- Empirical Mode Decomposition --- p.13 / Chapter 3.3 --- Result --- p.16 / Chapter Chapter 4: --- Possible relation with aerosols / Chapter 4.1 --- Introduction --- p.28 / Chapter 4.2 --- Area division according to Aerosol Optical Depth (AOD) --- p.29 / Chapter 4.3 --- High aerosol areas / Chapter 4.3.1 --- Southeast China --- p.33 / Chapter 4.3.2 --- Northern India --- p.36 / Chapter 4.3.3 --- Sahara Desert --- p.38 / Chapter 4.4 --- Multifractal Detrended Fluctuation Analysis (MF-DFA) --- p.42 / Chapter Chapter 5: --- Conclusion --- p.50 / Bibliography --- p.53

Electricity-driven air-conditioning is energy-intensive and puts a strain to many grids during hot periods in warm climates. Solar thermal cooling could be an alternative to conventional cooling, using a renewable energy source and supplying the most energy during peak demand periods with insignificant effect to the electric grid. Office buildings in warm climates have high cooling loads, naturally peaking during daytime because of occupancy and ambient temperature. Thus, office buildings have a seemingly advantageous relationship between the possible supply of solar thermal energy and cooling demand. With this background, solar cooling systems for two office buildings with the same dimensions are investigated, placed in a tropical- and a sub-tropical location. There are great differences in the design conditions for solar cooling systems in the tropics and the sub-tropics, between the chosen locations Manila and Abu Dhabi more specifically. Manila has a quite evenly distributed cooling load while Abu Dhabi has a strongly pronounced summer season with very high maximum cooling loads, while the winter temperatures are relatively low. The prior described conditions creates a big difference between loads throughout the year, making a thermal chiller less effective in this aspect. However Abu Dhabi is expected to have an overall smoother- and ultimately a more high performance solar cooling system due to lower humidity, which facilitates the important cooling of the chiller. Evacuated tube collectors were used at both sites, where the collectors in Manila needs to be larger relative to the chiller cooling capacity, in order to compensate for the irregularity of direct solar radiation. The electricity price in Abu Dhabi is too low for the solar cooling system to be economically feasible compared to a conventional system, where the net values over 20 years are 163 000 € and 127 000 €, respectively. Manila has on its hand a very high price for electricity, making the 20-year net values for both the solar cooling- and the conventional system approximately 170 000 €.

Graduation date: 2000

Thesis (Ph. D.)--University of California, San Diego, 2008. / Title from first page of PDF file (viewed July 22, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 203-220).

The aim of this dissertation is an attempt to' provide a general guide for future gold exploration in tropical and sub-tropical terrains. The dissertation includes a brief discussion of the various exploration techniques used in regional and local exploration. This provide the necessary background knowledge to discriminate between the constraints and applications and to be able to select the techniques which are more suitable for gold exploration in tropical and sub-tropical terrains. Weathering, gold geochemistry and soil formation, fields often neglected, are emphasized to illustrate the importance of the mobility and dispersion of gold in the weathering of the lateritic soil profile. A sound knowledge and experience in regolith mapping is to the advantage of the explorationist. Case studies with special emphasis on Central- and Western Africa are included to illustrate the effectiveness of some of the gold exploration techniques in tropical and sub-tropical terrains. Gold exploration is a highly complex and demanding science and to be successfull involves the full intergration of all geological, geochemical and geophysical information available. An intergrated exploration method and strategy would enhance the possibility of making viable discoveries in this highly competative environment where our mineral resources become more depleted every day. Where applicable, the reader is refered to various recommended literature sources to provide the necessary background knowledge which form an integral part of gold exploration.