Comparison of Satellite and ModelBased Heating Distributions

1
Comparison of Satellite and Model-Based Heating
Distributions
Understanding the differences between model-based
analyses and direct observations from satellite
is important for climate diagnostic studies as
well as satellite data assimilation applications.
Below is a comparison of ECMWF analyzed Q1 and
TRMM Microwave Imager (TMI) estimates of Q1-QR in
a tropical band (10 N - 10 S) on October 28,
1998. EC values of Q1 are substantially greater
than the Q1-QR estimates from TMI, especially
considering the fact that the TMI estimates would
be reduced by adding radiative cooling (QR).
Since net condensation heating in the atmosphere
is roughly equal to Lv x rain rate, the overall
magnitude difference here is traced to the EC
analyzed rain rates (lower panel ERA40) which
are generally greater than the TRMM 3b42 and
Olson TMI remote-sensing estimates plotted.
Limited temporal sampling by the TMI may account
for additional differences in heating magnitude.