Millimeter‐wave radiometry of deciduous trees at low‐depression angle

Abstract

Personnel from the Army Research Laboratory conducted experiments during the summer and early fall of 1996 to measure the low‐depression angle brightness temperatures of deciduous trees at 94 GHz. Changes in the signatures of five different deciduous trees were recorded over several months and related to infrared temperature, sky temperature, and leaf water content. Distinct differences were found in the brightness temperatures of the deciduous trees measured. The results of these measurements are presented and a good parametric fit to the data is made, showing the consistency of canopy emissivity and reflectivity over the measurement period. In addition, suggestions are made as to how future measurements could benefit from wideband, bistatic canopy cross‐section data.