This research addresses NASA Strat. Goal 3A, to "study Earth from space to advance scientific understanding..." and Precip. Sci. objectives 1.1-1.4, which call for space-time analysis of precipitation events in relation to climate, algorithms for latent heating, relating satellite-observed storms to hydrology, and generating better datasets for assessment of precipitation forecasting.
The objectives are to:
- Understand 3D structure of tropical convection and hurricanes from TRMM PR data;
- Develop latent and radiative heating algorithm methods for TRMM and GPM;
- Analyze orographic precipitation processes in the tropics with TRMM PR data and plan for GPM DPR studies of orographic precipitation in midlatitudes.
TASK 1 will analyze variations of MCS structure in the tropics via a specialized Cartesian-interpolated TRMM PR database generated at the UW. MCSs take on various 3D structures (Houze 2004, Rev. Geoph.). This study will identify favored types of MCS organization in different climatic regions. It will focus on convection over Africa and India, which have differing and robust MCS structures resulting from differing and robust large-scale forcing.
TASK 2 is similar in methodology to Task 1 but will examine tropical cyclones. A TRMM PR Cartesian data base of Atlantic hurricanes will be compiled and analyzed to charaterize the 3D structure of hurricane eyewalls and rainbands. Intensive observations of recent field campaigns such as RAINEX (Houze et al. 2006, BAMS) and TCSP will be used to interpret the data.
TASK 3 will contribute to the development of TRMM/GPM heating algorithms. It will link the structure of MCSs and hurricanes to heating algorithms. This work will follow Houze et al. (1980) and use the cloud system water budget as the way to assure that the anvil mass produced by observed precipitation systems is consistent with the latent heating. This approach will provide a constraint on latent heating estimates and guarantee that the radiative heating associated with anvils is consistent with the latent heating. This consistency is important because it is the combined effect of the latent plus radiative heating that determines how top heavy the overall heating profile is. The top heaviness in turn determines the nature of the large-scale response to the heating (e.g. Schumacher et al. 2004, J. Clim.).
TASK 4 will analyze the variation of our Cartesian TRMM PR 3D echo database in relation to the Himalayas, Andes, and other tropical mountain ranges. GPM will extend coverage of orographic precipitation to midlatitudes, where baroclinic precipitation systems are modified by orography as the pass over mountain barriers. The proposed research will prepare for GPM by studying vertically pointing radar data from the PI's midlatitude orographic studies (MAP & IMPROVE, Rotunno & Houze 2006, QJRMS) to develop methods for using the GPM DPR to extend orographic precipitation studies to midlatitudes.
