Traditionally, spaceborne scatterometers have been low resolution radar instruments designed to measure winds over the ocean. Because of their low resolution, the scatterometer measurements made over land have been used primarily to calibrate the instrument. However, studies of scatterometer measurements over land have hinted at the sensitivity of the scatterometer measurements to vegetation and ice coverage.
In a separate paper [7] we described a method for obtaining enhanced resolution radar images from low resolution scatterometer measurements. To validate our resolution enhancement scatterometer imaging technique, we have processed SASS data into radar images of the Amazon basin. We used this data to study and classify the observed vegetation and have found a remarkable correlation between the radar images and the vegetation type leading to impressive discrimination capability. Our results suggest that medium-scale, enhanced resolution scatterometer data can be useful in vegetation studies (see also [9]). We postulate that the enhanced data will be useful in a variety of other geophysical studies, e.g., ice [8].
Our resolution enhancement technique can be used to augment the data from existing and planned scatterometers as a ``technique of opportunity'', leading to more effective use of the instruments with little associated cost. In particular, applying the technique to SASS data provides a unique historical data set for studies in global change.
The wide-area, frequent coverage of the enhanced scatterometer data is particularily well suited for large-scale monitoring. The enhanced resolution scatterometer data can be used to extend the results of focused studies made in conjunction with high resolution sensors to much larger (continental) areas. The high absolute accuracy of the scatterometer measurements and their wide incidence angle diversity can be a significant advantage for geophysical modeling. While we have limited ourselves to SASS data in this paper, the technique can also be applied to the C-band ERS-1 scatterometer as well as other sensors.