Estimation of vertical air motion from dropsonde and radiosonde data

The theoretical calculation of droposnde fall rate and radiosonde balloon rise rate is made based on fluid dynamics and characteristics of radiosonde and dropsonde systems. The vertical air motion is estimated by subtracting theoretical fall/rise rate from GPS-measured vertical velocity. The technique is applied to data collected from five field experiments. The estimated vertical air velocity from IHOP dropsonde data shows very good qualitative agreement with the airborne Doppler lidar data. Estimated vertical wind profiles from 430 BAMEX dropsonde soundings show interesting six types of profiles. Overall, the technique works well for dropsonde data, but the uncertainty exists for radiosonde data. The theoretical calculation of balloon rise rate does not always work likely due to uncertainty in balloon volume and the drag coefficient, and their variations with height. The radiosonde estimated vertical motions associated with rotors in SRP data qualitatively agree with MAPR data. More comparisons with MAPR data will be conducted in the future.