Multi-spectral analysis of the Amazon basin using SeaWinds, ERS, Seasat scatterometers, TRMM-PR and SSM/I

The Amazon basin represents a vast geographical zone containing large proportion of global biomass. We use the SeaWinds scatterometer (QSCAT), ERS-1/-2 scatterometer (ESCAT), NASA scatterometer (NSCAT) Seasat scatterometer (SASS), Tropical Rain Measuring Mission Precipitation Radar (TRMM-PR) and Special Sensor Microwave/Imager (SSM/I) data to study the multi-spectral microwave response of Amazon vegetation. Incidence angle signatures of combined backscatter measurements (σ^o) from the scatterometers and precipitation radar indicate a good inter-calibration of the sensors. The multi-frequency signatures of both σ^o and radiometric temperature measurements (T_b) from SSM/I are also studied. Temporal variability of the Amazon basin is studied using C-band ERS data and a Ku-band time series formed by SASS, NSCAT and QSCAT data. ESCAT data reveals a possible mismatch in the calibration of scatterometers between ERS-1 and ERS-2. Although the central Amazon forest represents an area of very stable radar backscatter measurements, portions of the southern region exhibit backscatter changes over the past two decades.