A comparison of ground-based Doppler lidar and airborne in situ wind observations above complex terrain

Airborne wind observations collected by the National Oceanic and Atmospheric Administration’s (NOAA) WP-3D aircraft are compared with the winds retrieved by the NOAA/Environmental Technology Laboratory’s ground-based scanning Doppler lidar within the Wipp Valley during the Special Observing Period of the Mesoscale Alpine Programme. Comparisons are performed along individual  ight tracks and over an aggregated dataset consisting of all pairs of WP-3D and lidar observations that were approximately coincident in time and space. The impact of several different quality-control thresholds on the root mean square (r.m.s.) difference between the two observations is explored. The overall quality-controlled r.m.s. difference between radial wind speeds measured by each platform was 3.0 m s¡1 , with larger r.m.s. errors in the region up valley from the lidar than in the region down valley. A bias was also evident, in which the wind speeds from the WP-3D exceeded those from the lidar; this bias was small down valley (0.4 m s¡1) and much larger up valley (2.4 m s¡1).