Assessment of the Impact of Simulated Satellite Lidar Wind and Retrieved 183 GHz Water Vapor Observations on a Global Data Assimilation System

Abstract

A series of observing system simulation experiments (0SSEs) was conducted to assess the impacts on the Air Force Geophysics Laboratory (GL) global data assimilation system (GDAS) of a satellite Doppler wind lidar sounding system (WINDSAT) and of the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave (SSM) T-1 and T-2 temperature and moisture retrievals. (The SSM/T-2 is expected to be launched in the early 1990s.) In simulating the SSM data, some horizontal correlations were induced because the simulated errors had different biases in different geophysical regimes. As an interpretative aid we calibrated our results to a series of real data experiments. In an experiment in which the WINDSAT data is added to the observational database, the analyses and forecasts are improved relative to the control experiment. These improvements are large in the Southern Hemisphere extratropics. The addition of the SSM data improves the analysis of moisture particularly in the tropics and Southern Hemisphere extratropics.