HR: 1400h
AN: OS23E-06    [Abstracts]
TI: AMSU-A Measurements of Brightness Temperatures Over Amazon Rainforest
AU: * Mo, T
EM: Tsan.Mo@noaa.gov
AF: NOAA/NESDIS/Center for Satellite Applications and Research, 5200 Auth Road, Camp Springs, MD 20746, United States
AB: Angular distributions of brightness temperatures over the Amazon rainforest observed by the Advanced Microwave Sounding Unit-A (AMSU-A) window channels are studied and simulated with a radiative transfer model. The model is based on a combination of the atmospheric radiative transfer model and a vegetation canopy model which treats the rainforest as a uniform layer with an effective canopy temperature. Since emission from the ground surface is heavily attenuated by the rainforest canopy, only radiations from the rainforest canopy and the atmospheric medium contribute to the measurements. The measured angular distribution of brightness temperatures at the four window channels 1-3 and 15 (with frequencies centered at 23.8, 31.4, 50.3, and 89 GHz, respectively) has a relatively small angular dependence that is attributed to the atmospheric path length. Diurnal variation of the brightness temperatures observed by NOAA-KLM AMSU-A over Amazon Rain Forest is also investigated and modeled with Fourier Series. It shows that a second order of Fourier series can reproduce the observed pattern of diurnal variation of the brightness temperatures. The stable pattern and small variation of angular distributions can be potentially useful for post-launch calibration of new microwave radiometers. The AMSU-A is the first satellite borne instrument that has provided a large range of angular measurements of brightness temperatures over the Amazon rainforests and other global scenes. The establishment of a land calibration target is an important addition to the few tools available for calibration and validation of space-borne microwave instruments. Sample results will be presented and discussed.
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1632 Land cover change
DE: 1640 Remote sensing (1855)
DE: 3225 Numerical approximations and analysis (4260)
DE: 3322 Land/atmosphere interactions (1218, 1631, 1843)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly