Overview and Objectives: Characterization of particle size distributions (PSD) and microphysics for multiple precipitation regimes is critical to accurate space-borne measurement of precipitation. To support improved microphysical representation in satellite retrieval algorithms, we propose to employ University of Alabama-Huntsville (UAH) Hazardous Weather Testbed (HWT) instrumentation to study profiles of liquid, mixed, and ice-phase microphysical processes including PSDs. These studies will be conducted over the HWT for warm and cold season regimes under TRMM satellite coverage. Currently, TRMM 3A25 and 3A12 estimates of precipitation over the HWT differ by as much as 40% and exhibit systematic warm vs. cold seasonal biases. Hence, the objectives of this research are to:
- Conduct multi precipitation regime comparative studies of PSD microphysical profiles (liquid, mixed, ice) for assessment of discrepancy between ground and satellite-retrieved products;
- Apply results in (1) to melting-layer and cloud microphysical models used in PMM retrieval algorithms;
- Within the framework of (1) and (2), to further evaluate/develop PMM ground validation techniques.
Methods: The observational/analysis component will leverage the UAH ARMOR (C-band) and the UAH MAX (X-band, mobile) dual-polarimetric radars, a mobile 915 MHz wind profiler, a 12-channel Radiometrics profiling radiometer, two Parsival disdrometers, and a mesoscale rain gauge network. The multi-parameter/frequency, high resolution scanning and vertically pointing capabilities of the HWT convolved with heavy/frequent precipitation, multiple regimes, and frequent TRMM, A-train and AMSU-B overpasses enable robust sampling of PSD profile microphysics for comparison to satellite retrievals. Algorithm team members will apply results to test melting-layer, satellite simulator, and cloud-resolving models. Comparative studies of ground and space-observed ice water contents will be performed using TRMM and AMSU overpass data. A bridge to global application is provided by ongoing TRMM research which cross-types precipitation structures occurring over the UAH HWT with those of other regions around the globe.
Significance: Precipitation retrieval, validation and multi-satellite precipitation analysis:
- Improved facility algorithms for precipitation retrieval via microphysical process studies in multiple regime types (cold, warm season) under mid-latitude coverage of the TRMM and A-train satellites. The research team is comprised of observational and algorithm-scientists leading to efficient transfer of results to algorithms.
- Development of validation techniques for precipitation missions. The instruments used herein represent a significant subset of those proposed for future validation studies (e.g., GPM). This research will enable assessment of validation observational resources and methodologies.
- Development of new global products. This research will provide a framework for producing/improving retrievals of global ice-water content.
Impact on NASA's Earth Science Strategic Objectives: Improved quantification of the global hydrologic cycle via improvements in satellite precipitation retrieval algorithms.
