The use of ERS-1/2 Tandem interferometric coherence in the estimation of agricultural crop heights

In this study, the relationship between ERS-1/2 SAR Tandem interferometric coherence and the height of sugar beet, potato, and winter wheat is investi gated using measurements of crop growth and coherence. The development of b oth coherence and crop height is observed to be approximately linear during the early growing season, and linear crop-specific relationship's between tandem coherence and the heights of the studied crops are derived. The cohe rence of all the studied crops decreases as the crop heights increase, a pr obable explanation for this is that as the crop grows, it screens the groun d more effectively, and a greater part of the incident radar energy is back scattered from vegetation that decorrelates more rapidly than the more stab le soil. The relatively dense canopies of the root crops sugar beet and pot ato screen the ground considerably more effectively than the cereal crop wi nter wheat. This study gives a strong indication that ERS-1/2 Tandem interf erometric coherence is related to the height of agricultural crops, and tha t this relationship can be used to retrieve crop heights.