Diagnostic Wind Model Initialization over Complex Terrain Using the Airborne Doppler Wind Lidar Data

ABSTRACT

An initialization method using airborne Doppler wind lidar data was developed and evaluated for a massconsistent diagnostic wind model over complex terrain. The wind profiles were retrieved from the airborne lidar using a conical scanning scheme and a signal processing algorithm specifically designed for the airborne lidar system. An objective data analysis method in complex terrain was then applied to those wind profiles to produce a three-dimensional wind field for model initialization. The model results using the lidar data initialization were compared with independent surface weather observational data and profiles from a microwave radar wind profiler. The model was previously run for a small domain with simple terrain where comparisons with a surface observation array showed that the model performed well in a strong wind condition. For the more complex terrain in the Salinas valley, the model evaluation with a limited number of observations indicated that the diagnostic wind model with airborne Doppler lidar data also produced a reasonably good wind field in moderate to strong wind conditions. However, caution must be stressed for weak wind conditions in which the flow is thermally driven as the mass-consistent diagnostic wind model is not equipped to handle such cases. The effect of the lidar wind profile density over a simulation domain was also investigated for practical applications. The results indicate that about a half dozen lidar wind profiles would be adequate for a 20 by 20 km complex terrain domain with fairly uniform and moderate wind conditions.