Diagnostic Wind Model Initialization Using the Airborne Doppler Wind lidar Data Yansen Wang1, Chatt Williamson1, David Emmitt2, and Steve Greco2 1U. S. Army Research Laboratory 2Simpson Weather Associates AMS 4th Symposium on Lidar Atmospheric Application

. Very accurate boundary treatment, structured Cartesian grids. Brief 3DWF Model Description Given a limited number of observations or coarsely modeled wind field in a complex terrain, the wind field is physically interpolated in such way that the mass conservation is satisfied. Mathematically, to Minimize the following functional (Sasaki, 1970; Sherman 1978): . Very accurate boundary treatment, structured Cartesian grids. Bi-CGSTAB numerical and multigrid numerical solvers. Building and steep topographic wake parameterizations. Lidar data assimilation/initialization. Vegetation canopy flow parameterization. Validation and improvement with observation data sets. dV V z w y v x u E ò ú û ù ê ë é ¶ + - = ) ( , 2 1 l b

3DWF Askervein Hill Simulation Simulstion in Complex Terrain 3DWF Askervein Hill Simulation

3DWF wind field at 10m AGL A B AA A B AA

Comparison of model results with observations at Askervein Hill

3DWF model simulation wind field at Salinas Valley initialized by the airborne Doppler lidar data

Airborne Doppler Wind Lidar Optical Particle Counters Aircraft Platform Optical Particle Counters PCASP 0.1-3.0 m FSSP 2.5-51 m CAPS 0.45-118 m NPS CIRPAS Twin Otter Naval Postgraduate School Center for Interdisciplinary Remotely-piloted Aircraft Studies TODWL Instrument 2.0125 µm, coherent detection 2 mJ, 330 nsec (FWHM), 500 Hz 10 cm telescope two axis scanner, 30 & 120 deg, side door mount Weight: 425lb Power: 1.5KW ~7-10% total system efficiency TODWL Scanner

TODWL vs. Ft. Ord microwave sounder TODWL Flight Level

TODWL Flight Patterns

TODWL OBSERVATIONS

3DWF wind field at 10m AGL

Zoom in a small area

Comparison with NWS observations

Summary New 3DWF model performed well in a simple low hill with strong wind condition. Airborne Doppler lidar data can be used for the 3DWF initialization with an objective analysis method. The complex Salinas valley case with lidar data initialization gives reasonably good results.

TODWL Characteristics

0030 UTC 13 March 2002 TODWL sounding looking up (20seconds) Aircraft flight level TODWL sounding looking down (20 sec) Microwave sounding Ft Ord (30 minutes)