http://hdl.handle.net/10453/171 2013-05-19T13:10:34Z http://hdl.handle.net/10453/12779 Synthetic Aperture Radar (L band) and Optical Vegetation Indices for Discriminating the Brazilian Savanna Physiognomies: A Comparative Analysis Sano E.; Ferreira L; Huete Alfredo The all-weather capability, signal independence to the solar illumination angle, and response to 3D vegetation structures are the highlights of active radar systems for natural vegetation mapping and monitoring. However, they may present significant soil background effects. This study addresses a comparative analysis of the performance of L-band synthetic aperture radar (SAR) data and optical vegetation indices (VIs) for discriminating the Brazilian cerrado physiognomies. The study area was the Brasilia National Park, Brazil, one of the test sites of the Large-Scale Biosphere¿Atmosphere (LBA) experiment in Amazonia. Seasonal Japanese Earth Resources Satellite-1 (JERS-1) SAR backscatter coefficients (?°) were compared with two vegetation indices [normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI)] over the five most dominant cerrados¿ physiognomies plus gallery forest. In contrast to the VIs, ?° from dry and wet seasons did not change significantly, indicating primary response to vegetation structures. Discriminant analysis and analysis of variance (ANOVA) showed an overall higher performance of radar data. However, when both SAR and VIs are combined, the discrimination capability increased significantly, indicating that the fusion of the optical and radar backscatter observations provides overall improved classifications of the cerrado types. In addition, VIs showed good performance for monitoring the cerrado dynamics. 2005-01-01T00:00:00Z http://hdl.handle.net/10453/12778 Heat budget and thermal microenvironment of shallow-water corals: Do massive corals get warmer than branching corals? Jimenez Denness Isabel; Kuhl Michael; Larkum Anthony; Ralph Peter Coral surface temperature was investigated with multiple temperature sensors mounted on hemispherical and branching corals under (a) artificial lighting and controlled flow; (b) natural sunlight and controlled flow; and (c) in situ conditions in a shallo 2008-01-01T00:00:00Z http://hdl.handle.net/10453/12775 Compensatory effects of boat wake and dredge spoil disposal on assemblages of macroinvertebrates Bishop Melanie Estuarine assemblages are exposed to multiple disturbances that. overlap in time and space. Along the Atlantic Intracoastal Waterway (east coast, United States), two disturbances that frequently co-occur are the production of wake by boats and the dispos 2005-01-01T00:00:00Z http://hdl.handle.net/10453/12774 Terrestrial Carbon Sinks for the United States Predicted from MODIS Satellite Data and Ecosystem ModelingTerrestrial Carbon Sinks for the United States Predicted from MODIS Satellite Data and Ecosystem Modeling Potter Christopher; Klooster Steven; Huete Alfredo; Genovese Vanessa A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of the conterminous United States over the period 2001¿04. Predicted net ecosystem production (NEP) flux for atmospheric CO2 in the United States was estimated as annual net sink of about +0.2 Pg C in 2004. Regional climate patterns were reflected in the predicted annual NEP flux from the model, which showed extensive carbon sinks in ecosystems of the southern and eastern regions in 2003¿04, and major carbon source fluxes from ecosystems in the Rocky Mountain and Pacific Northwest regions in 2003¿04. As demonstrated through tower site comparisons, net primary production (NPP) modeled with monthly MODIS enhanced vegetation index (EVI) inputs closely resembles both the measured high- and low-season carbon fluxes. Modeling results suggest that the capacity of the NASA Carnegie Ames Stanford Approach (CASA) model to use 8-km resolution MODIS EVI data to predict peak growing season uptake rates of CO2 in irrigated croplands and moist temperate forests is strong. 2007-01-01T00:00:00Z