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Comments on the GroundWinds NH 2000 Intercomparison

Campaign

James G. Yoe

M.K. Rama Varma Raja

Core Questions

• Are the DWL’s LOSH measurements consistent with the (accepted) wind?

• Did the optical instruments provide LOSH wind measurements in agreement with one another?

• Answer: yes – signal permitting

Approach to addressing

• Examination of “best” dataset– Use most extensive set of observations– Stationary atmospheric conditions prevailing

• Departures recognizable

– Data processing/products considered optimal – 09/28/00

Profiles of radiosonde wind speed & direction on 28/29 September 2000.

Initially clear conditions give way to a thick, descending cloud layer near 5 km between 0000 - 0300 UT on 09/29/00. (GLOW total photon counts display similar structure.)

Time-height section of mini-MOPA SNR 09/28/00 - 09/29/00. The cloud layer visible as enhanced SNR at 4-6 km.

Time-Height section of GroundWinds (molecular) 1-min LOSH velocities.

Time-height section of uncertainty reported for 1-min radial velocity for GroundWinds (molecular channel.)

Time-height section of GLOW 1-min LOSH velocities.

Mean Difference= -1.51 m/s

SD of MD = 5.18 m/s

Size= 198

Mean Difference = -1.84 m/sSD of MD = 4.66 m/sSize= 132

Mean Difference =1.0 m/sSD of MD = 4.67 m/sSize= 78

Mean Difference= -2.51 m/sSD = 5.58 m/sSize= 78


Mean Difference =0.23 m/sSD of MD = 2.24 m/sSize=140

Mean Difference = -2.78 m/sSD of MD =2.04 m/sSize=166


Mean Diff. =-1.25 m/sSD of MD =3.04 m/sSize=193

Mean=-1.07 m/sSD=2.55 m/sSize=567

Mean=-1.17 m/sSD=2.67 m/sSize=762

Mean Difference =-0.7 m/s

SD of MD =5.57 m/s

Size=361

Mean Difference=-3.76 m/sSD of MD =8.19 m/sSize =114 (120)

The horizontal separation of radiosondes and Doppler Wind Lidar sampling volumes as functions of height.

Profiles of radiosonde relative humidity & temperature on 09/28/00 and 09/29/00. Note descending, thickening cloud layer

Mean=0.07 m/sSD=5.42 m/sSize=247