Alaska Satellite Facility - Distributed Active Archive Center

Terrestrial Ecology – Data Application

PALSAR Terrestrial Biophysical Applications

The data can be used for a number of purposes: (1) to validate the synthetic aperture radar (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 and forest change analysis.

The Phased Array L-band Synthetic Aperture Radar (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.

Quantitatively Comparing Multi-Temporal Data

The data values in the image are Digital Numbers (DN) that can be used in the following equation to extract the Normalized Radar Cross Section (NRCS).

NRCS (dB) = 10*log10(<DNˆ2>) + CF

Where the Calibration Factor (CF) is a constant -83. 

The cross section parameter is useful to quantitatively compare multi-temporal data.