The Terrestrial Ecology products were created using ALOS PALSAR data. To make the SAR scenes more user friendly, the polarization data was classified as reds, greens, and blues in the image. The ranging data are terrain-corrected by a process that assigns the ranging values to geographic coordinates by utilizing a digital surface model (DSM). High-resolution DSM data are not available for the entire planet and existing data at high latitudes is problematic, especially in areas of very little terrain relief, such as sheet glaciers. To use a consistent DSM for this project and all of the sites being investigated, the DSM data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imaging instrument was used for the terrain correction.
The data can be used for a number of purposes: (1) to validate the SAR measurements using flux tower site characterization data; (2) to examine the impacts of vegetation dynamics on climate; (3) to understand human impacts on vegetation at a local scale; (3) to detect deforestation and forest degradation; (4) to map and differentiate growth stages and change; (5) to retrieve woody biomass and structural attributes; and (6) to characterize, map and monitor ecoregions such as mangroves and wetlands.
Satellite radar can be important to Earth system monitoring because the properties of the signal return are better suited for certain vegetative biophysical estimates and are more accurate or not otherwise obtainable by passive remote sensing systems. A number of studies have shown a significant relationship between L-Band SAR backscatter coefficients and forest structure parameters including above-ground biomass and vegetative structural attributes. Other examples of terrestrial applications include wetland characterization, mapping, and monitoring forest change analysis.
The PALSAR subsets provided in this data set might be useful for visual interest and preliminary analysis of the field area. For in-depth analyses, such as biomass estimation, vegetation characterization, etc., users might have to download the lower level products from ASF.
