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Precipitation and Latent Heating Distributions from Satellite Passive Microwave RadiometryA revised Bayesian algorithm for estimating surface rain rate, convective rain proportion, and latent heating profiles from satellite-borne passive microwave radiometer observations over ocean backgrounds is described. The algorithm searches a large database of cloud-radiative model simulations to find cloud profiles that are radiatively consistent with a given set of microwave radiance measurements. The properties of these radiatively consistent profiles are then composited to obtain best estimates of the observed properties. The revised algorithm is supported by an expanded and more physically consistent database of cloud-radiative model simulations. The algorithm also features a better quantification of the convective and nonconvective contributions to total rainfall, a new geographic database, and an improved representation of background radiances in rain-free regions. Bias and random error estimates are derived from applications of the algorithm to synthetic radiance data, based upon a subset of cloud-resolving model simulations, and from the Bayesian formulation itself. Synthetic rain-rate and latent heating estimates exhibit a trend of high (low) bias for low (high) retrieved values. The Bayesian estimates of random error are propagated to represent errors at coarser time and space resolutions, based upon applications of the algorithm to TRMM Microwave Imager (TMI) data. Errors in TMI instantaneous rain-rate estimates at 0.5 -resolution range from approximately 50% at 1 mm/h to 20% at 14 mm/h. Errors in collocated spaceborne radar rain-rate estimates are roughly 50%-80% of the TMI errors at this resolution. The estimated algorithm random error in TMI rain rates at monthly, 2.5deg resolution is relatively small (less than 6% at 5 mm day.1) in comparison with the random error resulting from infrequent satellite temporal sampling (8%-35% at the same rain rate). Percentage errors resulting from sampling decrease with increasing rain rate, and sampling errors in latent heating rates follow the same trend. Averaging over 3 months reduces sampling errors in rain rates to 6%-15% at 5 mm day.1, with proportionate reductions in latent heating sampling errors.
Document ID
20070031556
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Olson, William S. (Maryland Univ. Baltimore County Baltimore, MD, United States)
Kummerow, Christian D. (Colorado State Univ. Fort Collins, CO, United States)
Yang, Song (George Mason Univ. Fairfax, VA, United States)
Petty, Grant W. (Wisconsin Univ. Madison, WI, United States)
Tao, Wei-Kuo (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Bell, Thomas L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Braun, Scott A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Wang, Yansen (Maryland Univ. Baltimore County Baltimore, MD, United States)
Lang, Stephen E. (Science Systems and Applications, Inc. Lanham, MD, United States)
Johnson, Daniel E. (Maryland Univ. Baltimore County Greenbelt, MD, United States)
Chiu, Christine (Maryland Univ. Baltimore County Baltimore, MD, United States)
Date Acquired
August 23, 2013
Publication Date
May 1, 2006
Publication Information
Publication: Journal of Applied Meteorology and Climatology
Volume: 45
Subject Category
Meteorology and Climatology
Report/Patent Number
JAM2369
Distribution Limits
Public
Copyright
Other