SEASONAL EVOLUTION OF MICROWAVE-RADIATION FROM AN OAT FIELD

Microwave brightness temperatures at five frequencies from 4.9 GHz to 94 GHz of an oat field were measured from seeding to harvest in 1989. The data were compared with observed soil and vegetation parameters. The reduction of the soil moisture sensitivity during the growth phase was quantitatively related to plant water content with data at 4.9 GHz. At higher frequencies the influence of vegetation is almost abruptly changing the emission with respect to the plant development. The different spectral and polarization behavior can be related to geometrical vegetation parameters such as leaf and panicle size and orientation. © 1990.