Experimental study on directionality in thermal infrared observations of corn canopy

In order to investigate the directional distribution of thermal infrared radiance from corn canopy, a field campaign was elaborately schemed in North-China-Plain from July to August, 2000. Corn was designed to be row planted and uniformly planted, to simulate the typical structures of agricultural canopy. One TIR radiometers was set at an automatic multi-angular observation bracket while another was fixed nadir-view over the crop canopy. Directional TIR radiance distributions were measured every two hours at several typical weather conditions during different corn growth stages. Canopy structural parameters and meteorological parameters were also measured simultaneously. After temporally normalized, the directional TIR radiance distributions were extracted, diurnal and seasonal variation of the directionality is analyzed.