Estimating forest vertical structure from multialtitude, fixed-baseline radar interferometric and polarimetric data

This paper demonstrates the feasibility of using multialtitude, fixed-baseline INSAR to estimate vertical-structure parameters of forests. Two model scenarios applied to C-band INSAR data collected at 8-km and 4-km altitudes over central Oregon with TOPSAR suggest the need for either a ground surface contribution with a single vegetation layer or a two-layer vegetation model. The two layer model parameters seem more reasonable and qualitatively reflect the field-measured characteristics of the forest studied. The parameters produced from the single set of INSAR cross-correlations in this paper do not constitute a proof that multialtitude INSAR will reliably produce vertical structure parameters, but they do prompt future, more complete demonstrations. A complete set of amplitudes and phases will be used in parameter estimation scenarios, augmenting those shown in (2) and (3), from 2-, 4-, and 8-km altitude INSAR. Including polarimetry in the observation vector will constrain ground/volume power fractions and terrain slope parameters