Instrument configuration for Dual Doppler Lidar co-planar scans: METCRAX II

The Second Meteor Crater Experiment (METCRAX II) was designed to study downslope-windstorm-type flows occurring at the Barringer Meteorite Crater in Arizona. Two Doppler wind lidars were deployed to perform a Co-planar Dual Doppler lidar analysis to capture the 2D vertical structure of these flows in the crater basin. This type of analysis allows the flow to be resolved on a 2D Cartesian grid constructed in the RHI scan overlap region. Previous studies have shown that the dominant error in the Co-planar Dual Doppler analysis mentioned above is due to the under sampling of radial velocities. Hence, it is necessary to optimize the setup and choose a scan strategy that minimizes the under sampling of radial velocities and provides a good spatial as well as temporal coverage of these short-lived events, which in turn strongly depend on the lidar parameters and the grid spacing.

To optimize the lidar parameters for the METCRAX II field experiment, a lidar simulator was developed using an LES wind field. A wind retrieval technique based on the weighted least squares method with weights calculated based on the relative location of the lidar range gate centers to the grid intersection points was developed. An optimal instrument configuration was devised by comparing the simulator retrievals to the LES-modeled background wind field. Details about the lidar simulator and early results from the field experiment will be presented.