InSAR for estimation of changes in snow water equivalent of dry snow

This study describes the theoretical relation between interferometric phase and changes in dry snow Snow Water Equivalent (SWE) or snow depth. Results from experiments using three ERS-1/2 tandem datasets from Norway obtained in middle of March (dry snow), late May (wet snow) and late July (snow free) are also reported. Presented theory and results implies that even small changes in snow properties between InSAR acquisitions introduces a significant error in DEM derived from glaciers, ice sheets or ground, even in the case of high coherence. Accordingly, the height error (or range displacement) can also be used to estimate changes in dry snow SWE or depth. A snow density of 0.3 g/cm/sup 3/ at 23/spl deg/ incidence angle gives phase wrapping for changes in snow depth of 10 cm, equal to a SWE of 3,0 cm.