This research proposal is in response to the NASA Research Announcement (NRA) NNH06ZDA001N, entitled 'Research Opportunities in Space and Earth Sciences - 2006' - A.8 'Precipitation Science'. The objectives of the proposal address topic 1.4 'Improvements in Weather Forecasting Capabilities', sub-topics (1) and (2).
The European Centre for Medium-Range Weather Forecasts has implemented a methodology for the assimilation of rain affected passive microwave observations from space in June 2005. The system is computationally efficient and produces improved initial moisture conditions, mainly in the Tropics. The system is based on the usage of data from three Special Sensor Microwave Imagers. In preparation of enhanced furture satellite observing systems that are planned with the implementation of the Global Precipitation Measuring mission, an assessment of the impact of such systems in state-of-the-art numerical weather prediction systems is required. In this project, it is proposed to undertake observing system experiments that evaluate the impact of different configurations of existing microwave radiometer systems that provide observations of clouds and precipitation on short to medium-range weather forecasts. The impact will be compared against system configurations that represent (1) a basic conventional observing system, (2) the basic system plus clear-sky moisture observations from space, and (3) the full operational observing system. This evaluation will allow to quantify the potential value of rain observations from a satellite constellation and provide insights into system optimization and limitations. All experiments will be performed with the current global operational four-dimensional variational assimilation system.
