HR: 08:45h
AN: H31I-04 INVITED    [Abstracts]
TI: Towards a Fully Integrated Rainfall Algorithm for GPM
AU: * Kummerow, C D
EM: kummerow@atmos.colostate.edu
AF: Colorado State University, Dept. of Atmospheric Science, Fort Collins, CO 80523-1371, United States
AB: The Global Precipitation Mission (GPM) will consist of a core spacecraft carrying a dual frequency (Ku/Ka) radar and a state-of-the-art passive microwave radiometer. In addition, the GPM concept includes a constellation of dedicated and existing spaceborne radiometers. Because existing radiometers are not under the configuration control of GPM, it is unwise to plan for algorithms that are optimized on planned or reported sensor characteristics. Instead, it is desirable for a single algorithm to accommodate any sensor in such a way that the information content of the sensor and not the specific sensor design (e.g., channel selection, view angles, spatial resolution) drive the final solution. A parametric algorithm for use by GPM is being constructed using current TRMM data. It begins by retrieving nonraining parameters when the radar detects no rainfall. An optimal estimation (OE) technique is used because it ensures that all sensor frequencies are matched between observations and retrieved geophysical parameters. This OE approach is quite robust over oceans but still requires refinement over land where theoretical models for the surface emissivity are still evolving. Synergy with other sensors and efforts is particularly critical over land. When the radar detects rainfall, cloud resolving models (CRMs) are matched to the radar reflectivity profile as a first guess. Radiative transfer computations are used to determine theoretical TMI brightness temperatures and these are in turn compared to the actual observations. Where there is no agreement, the DSD and ice density assumed by the radar are modified and the procedure is repeated until convergence between radar and radiometer is achieved. These products form an a-priori database, which radiometer only techniques can then exploit to create consistent rainfall products from diverse microwave sensors.
DE: 0321 Cloud/radiation interaction
DE: 0480 Remote sensing
DE: 1854 Precipitation (3354)
DE: 1855 Remote sensing (1640)
SC: Hydrology [H]
MN: 2007 Fall Meeting