Prediction and Verification of the Observation Errors for Space-based lidar Measurements of Wind Profiles

Rod Frehlich

CIRES, University of Colorado

Boulder, CO 80309

Phone:303-492-6776 FAX:303-492-1149 Email:rgf@cires.colorado.edu

and

RAP/NCAR

Boulder, CO 80307

Phone (NCAR): 303-497-2848 Email (NCAR): frehlich@ucar.edu

Verification of the accuracy of space-based wind measurements will be difficult because of the random variations of the atmospheric velocity field over the measurement volume. The definition of accuracy requires a definition of ``truth". Truth is defined as the spatial average of the random velocity over the measurement volume. The random errors of Doppler lidar measurements produced by the instrument as well as the sampling or representative error from the lidar scanning geometry are discussed. The results are compared with the sampling error produced by ideal rawinsonde measurements and aircraft winds. The verification of space-based measurements using consistency in the data and using the correlation between rawinsonde measurements and aircraft winds is also investigated for typical tropospheric conditions. The implications of these results on data assimilation algorithms and models will be presented.