713 Validation of Ground-Based Doppler Lidar Measurements of Atmospheric Wind Profile Observations

Wednesday, 9 January 2013
Exhibit Hall 3 (Austin Convention Center)
Mary Morris, Univ. of Michigan, Ann Arbor, MI; and K. Vermeesch, B. Gentry, B. B. Demoz, and H. Chen

Tropospheric wind observations are an important factor in numerical weather prediction, climate modeling, wind-generated electricity, and air transportation. Despite the importance of global tropospheric wind observations, a satellite mission has yet to be planned for this purpose. In order to develop a Doppler lidar satellite mission for measuring tropospheric wind globally, ground and aircraft based Doppler lidar systems must be tested and validated. Comparisons between a Doppler lidar system, named the Goddard Lidar Observatory for Wind (GLOW), with radiosondes and wind profilers have been made.

In support of these comparisons, this study completed a comparison between observations taken from radiosondes and a 915 MHz boundary-layer wind profiler. From this comparison between radiosonde and wind profiler observations, along with the lidar/radiosonde and lidar/profiler comparisons performed previously, we will eventually be able understand how the different instruments perform in various atmospheric conditions.

Matlab was used to compare the observations taken at corresponding times and heights. Data from a ceilometer were used to further investigate events where a detailed description of the structure of the atmosphere could explain why the wind observations differed by a significant amount. To date, only data from 2010 has been analyzed. After looking through the comparisons manually for significant outliers, a set of dates where the instruments observed significantly different wind speeds was compiled for further analysis of the environmental setup. This led to a characterization of when each instrument performs best.

This study found that the 915Mhz profiler performed best during the summer, when there is more convection and mixing in the planetary boundary layer. The water vapor mixing ratio and aerosol scattering ratio mix deeper into the boundary layer in the summer months, which generally improves the performance of the profiler.

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