2.10
Estimation of Cloud Properties over Oceans Using VIRS and TMI Measurements on the TRMM Satellite
Shu-peng Ho, AS&M, Inc., Hampton, VA; and B. Lin and P. Minnis
An MVI (microwave, visible and infrared) method (Lin et al.,1998) was adapted and applied to data collected from the TMI (TRMM Microwave Imager) and the VIRS (Visible and Infrared Scanner) to estimate cloud and atmospheric properties. Cloud products, i.e., cloud optical depth, cloud fraction, and cloud top temperature retrieved from VIRS were collocated with TMI measurements. Atmospheric and water-cloud properties retrieved over open oceanic regions using a combination of the VIRS and TMI datasets include sea surface temperature (SST), surface wind speed (WS), column water vapor (CWV), LWP, cloud liquid water temperature (Tw), effective droplet radius (Re) and the frequency of multi-layered, non-precipitating clouds. SST and WS over the Pacific Ocean are strongly associated with the Southern Oscillation Index (SOI). CWV is very important quantity for the climate feedbacks. LWP retrieved from TMI measurements with a microwave retrieval method are compared with those from VIRS data derived with an optical method (Minnis et al., 1995) to cross-validate the accuracy of the LWP estimates. The zonal mean of TMI LWP for warm non-precipitating clouds is very close to that of VIRS LWP. The global mean TMI LWP for July 1998 for warm non-precipitating clouds is 0.0575 mm and that of VIRS LWP is 0.0638 mm. Regional comparison of TMI LWP and VIRS LWP for overcast, non-precipitating water clouds over the north Atlantic (25-40 N, 330-345 E) shows that the correlation coefficient is about 0.757. The occurrence of multi-layered non-precipitating clouds was inferred from LWP and cloud water temperature (Tw) retrieved from TMI and cloud top temperature (Tc) retrieved from VIRS. Global co-occurrences of low clouds, middle clouds and high clouds are estimated.
Session 2, Interrelationships Between Oceanographic and Atmospheric Observing Systems (NOPP Special Session)
Monday, 15 January 2001, 2:00 PM-6:00 PM
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