[Seminar on 10 July] Observing System Simulation Experiments for Space-based Doppler Wind Lidar Observations
Dr. Zai-Zhong Ma
NOAA/JCSDA Univ. of Maryland /ESSIC
No.319, Building 40, IAP
10:00, 10 July 2014
The three-dimensional global wind field is the most important remaining measurement needed to accurately assess the dynamics of the atmosphere. Wind information in the tropics, high latitudes, and stratosphere, is particularly deficient. Furthermore, only a small fraction of the atmosphere is sampled in terms of wind profiles. This limits our ability to optimally specify initial conditions for numerical weather prediction (NWP) models and our understanding of several key climate change issues.
Because of its extensive wind-measurement heritage (since 1968) and especially the rapid recent technology advances, Doppler lidar has reached a level of maturity required for a space-based mission. The Global Wind Observing Sounder (GWOS) concept, which has been developed by NASA in response to the National Research Council Decadal Survey, is expected to provide global wind profile observations with high vertical resolution, precision, and accuracy when realized. The assimilation of lidar wind data anticipated from the GWOS is being conducted as a series of Observing System Simulation Experiments (OSSEs) at the Joint Center for Satellite and Data Assimilation (JCSDA).
A significant reduction of the stratospheric RMSE of vector wind analyses is found for all latitudes when lidar wind profiles are used in the assimilation system. In addition, the anomaly correlations (AC) of geopotential height forecasts at 500 hPa were evaluated to compare the control and different GWOS telescope configuration experiments. The results show that the assimilation of lidar data from the GWOS can improve the NCEP GFS wind and mass field forecasts.