TIR observations in FIFE from field, aircraft and satellite platforms

Observations of the surface radiometric temperature by the AVHRR sensor on board the NOAA-9 satellite are presented. The satellite observations were corrected for atmospheric effects using a path radiance model (MODTRAN3) and radio soundings of the atmosphere. Problems with this approach include the non-simultaneity of the soundings with the overpass and errors involved in profile measurements. For the former, soundings before and after the overpass were interpolated to the time of the overpass. For the latter, the errors arise from the +/-0.5 C uncertainty in the dry and wet bulb temperatures which produces a +/-14% relative uncertainty in the water vapor. To over come this the water vapor profiles were adjusted until the channel 4 and 5 temperature differences over a large reservoir were reduced to zero. This adjusted profiled was then used over the entire site. The results are compared to ground broadband temperature readings at about 10 sites and to aircraft results from the thermal channel of the NS001 sensor on the C-130 aircraft and found to be in good agreement considering the difference in footprint sizes