Monday, 10 January 2005: 1:30 PM
Evaluating various Lidar-based wind analysis schemes against independent observations.
The Pentagon Shield project was a month long field experiment to measure the wind field in and around the Pentagon at high spatial and temporal resolution. A number of wind measuring instruments were used including a Doppler lidar, SODAR, tethersonde, 30 meter tower as well several surface observing stations. The Doppler lidar has the best wind observing capability in terms of coverage and spatial/temporal resolution. However, the observations from the Doppler lidar are restricted to just one component of the three-dimensional wind, the radial component. During, and after, the experiment a number of wind analysis schemes were run on the lidar data in an effort to retrieve some of the unobserved components of the wind field. In this study we will evaluate these different methods using some of the independent observations.
The analysis schemes can be separated into two main categories; those that determine a single profile of the horizontal wind and those that determine the three-dimensional wind over a three-dimensional volume. In the first category are three schemes; VAD (Velocity Azimuth Display) and two versions of VVP (Volume Velocity Processing). The output from these three schemes have been compared against the SODAR data for the month long experiment. The three-dimensional scheme is the Variational Lidar Analysis Scheme (VLAS) which fits a numerical model over time to the lidar data. The output from VLAS is currently being compared to some of the independant data sources, results will be presented at the Symposium.