Thursday, 6 June 2002: 11:15 AM
Evaluation of radiometric measurements from the NASA Multi-Angle Spectro-Radiometer from an inhomogeneous cloud using a combination of 2D and 3D radiative transfer modeling and airborne measurements
In December 1999, NASA launched the EOS AM1 satellite. This platform
carries 5 instruments whose purpose is to measure important properties of
the Earth climate system. One of these instruments is MISR, the Multi-
Angle Spectro-Radiometer. This instrument measures the light reflected
from the Earth at high resolution (~275 m) at four wavelengths (three in the
visible and one in the near IR) and at nine different viewing angles that
vary from +70 to -70 degrees along the direction of flight of the satellite.
This multi-angle data has the potential to provide information on aerosols,
surface and cloud characteristics which compliments traditional single-
view-direction satellite measurements. Before this potential can be
realized, the accuracy of the satellite radiance measurements must be
carefully assessed and the implications of the radiometric accuracy on the
remote sensing algorithms evaluated. In this presentation, we show a
comparison of the MISR multi-angle measurements and 2D radiative
transfer simulations from an inhomogeneous cloud scene. The inputs to the
radiative transfer code are based entirely on independently gathered data
(ground-based radar, lidar, microwave radiometer, in situ aircraft data,
etc.). It is found that the 2D radiative transfer solution compares favorably
in the forward scattering directions, but is off by as much as 10% in the
backscattering directions. Using 3D radiative transfer modeling, we show
that this difference is due to the cloud 3D structure. Comparison of the
simulations to the MISR measurements, after accounting for 3D effects,
show residual differences which are less than 4% at all angles.
Supplementary URL: