Tropical convection drives the climate and can be seen clearly from space, yet our capacity to use this information in forecast and monitoring systems is nascent. Thus the full scientific and social benefits available from the TRMM/GPM missions remain to be unlocked. While persistence in SSTs is well studied, less analysis has been applied to the satellite rainfall record. Recent warming and changes in tropical precipitation patterns have been substantial and these variations are linked to life-sustaining terrestrial rainfall in the tropics and sub-tropics, where projections call for 2-7 billion water insecure people by 2050. Our efforts will create an integrated dataset, improve hydrologic monitoring and rainfall predictions, and increase our understanding of the links between small scale precipitation events and large scale climate variations and change.
Our research will begin by developing a semi-integrated 'hydrologic monitoring system' combining 0.25� terrestrial precipitation and actual evapotranspiration fields with SSM/I-derived oceanic evaporation and moisture transports. Preliminary evaluation suggests that tropical oceanic precipitation is associated with fairly predictable moisture transport anomalies at coarse reanalysis scales. We will use TRRM-TMI-SSM/I data to explore and validate these relationships at higher resolutions, and discuss scaling between daily - 0.25� and the seasonal - 2.5� scales. We will examine persistence, linking oceanic precipitation extremes to changes in onshore moisture transports and terrestrial precipitation in Africa, Asia and Central/South America. This will improve our current NASA CAN 1- to -3 month forecast system. Our work will conclude by using model output statistics (MOS) and IPCC simulations to estimate terrestrial rainfall and AET for 2030-2050. Implications for food/water security will be evaluated and presented to USAID.
These objectives are consistent with many key topics in the NRA. We address most of the Precipitation Variability components. We examine climatically significant variations in oceanic precipitation and link their space-time evolution to terrestrial impacts. The prognostic contribution of satellite observations will be evaluated statistically, guiding future assimilation and reanalysis efforts. We will quantify GPM in ways that elucidate variations in oceanic and terrestrial rainfall and identify new means of evaluating accelerations and changes to the hydrologic cycle. Our efforts apply to the Retrieval Algorithm topic by demonstrating new algorithms for reducing precipitation bias in areas with complex terrain. We contribute to the Applications to Hydrology component by developing a modeling methodology for large-basin ET and evaluating the agro-hydrological impacts of simulated 2xC02 satellite precipitation. The data/technology produced will contribute to the Education topic by enhancing the timely development and delivery of both global and regional rainfall products.
