Line-of-Sight Wind Products

For each DWL line of sight perspective, a profile of forward model winds at each range gate is computed using the input horizontal wind components (converted to along track and cross track perspectives), platform geometry and the sampling scale uncertainties. 

V_for = ((U_ct+s_u* GN) * cos(ß) + (V_at+s_v* GN) * sin(ß)) * cos(Q) + W_vv+(s_w* GN) * sin(Q)

where

         V_for - the forward model line-of-sight wind velocity (m/s)

          U_ct - the cross track wind velocity at the shot location (m/s)

         s_{u - the sampling scale uncertainty in the cross track wind (m/s)}

         GN - gaussian distributed random number

        ß - heading angle (rad)

        V_at - the along track wind velocity at the shot location (m/s)

         s_{v - the sampling scale uncertainty in the along track wind (m/s)}

        Q - the elevation angle (rad)

         W_vv - the vertical velocity at the shot location (m/s)

     s_{w - the sampling scale uncertainty in the vertical velocity (m/s)}

The simulated DWL line-of-sight wind velocity is calculated by adding the line-of-sight uncertainty derived from the DWL's signal-to-noise model  to the forward model wind as follows:

where

         V_los - the line-of-sight wind velocity (m/s)

         s_los - the line-of-sight uncertainty (m/s).

DWL Shot Accumulation (grid volume averaging)

The Lidar Simulation Model estimates the performances of a pulsed DWL for a user-defined grid volume in order to define a lidar measurement of the line of sight wind.  The LSM supports two methods; single measurement LOS accumulation and multiple measurement volume accumulation.

Single shot mode: Along each DWL line of sight, each pulse within the user's defined vertical thickness resolution (with respect to the ABL) is accumulated to contribute to the DWL LOS wind estimate as depicted in the following figure:

 Accumulation Mode: The method the MLSM accumulates each pulse over an user-defined grid volume depends upon the user's scan mode: either conical or step/stare. 

For a conically scanned DWL, the grid volume is defined horizontally by the user's angle bin and number of scans for shot accumulation (shown in figure below) and the previously discussed vertical accumulation. Since this configuration is not likely and is only included in the MLSM for statistical purposes, the user is strongly cautioned when using this option. 

For step/stare DWL, the grid volume is defined horizontally by each dwell time of the stare and the previously discussed vertical accumulation. The percentage of shots to accumulate in a stare is preset to 100% in the MLSM Version 1.0.

Horizontal Wind Products  (The LSM's Horizontal Wind Models are not included in the MLSM version 1.0) 

Last Updated: 02/07/2007