The Doppler Aerosol Wind (DAWN) Lidar during CPEX 2017: Performance Assessment, Data Processing, and Data Products

In May-June 2017, NASA conducted the airborne 2017 Convective Processes in the Tropics Experiment (CPEX) which featured the Doppler Aerosol WiNd (DAWN) lidar along with dropsondes and other remote sensing instruments aboard a NASA DC-8 aircraft. With a goal to study convective processes and circulations in the tropics, sixteen NASA DC-8 missions were flown into the Gulf of Mexico, Caribbean Sea, and the Atlantic Ocean where a comprehensive set of observations (particularly winds from DAWN and the dropsondes) were taken near isolated, scattered, and organized deep convection during all phases of the convective life cycle.

DAWN is NASA’s most capable airborne wind-profiling lidar and utilizes a 2-micron laser that pulses at 10 Hz and has previously participated in NASA GRIP (2010) and Polar Winds (2014-15) airborne campaigns. As will be shown, the DAWN can provide high resolution (4 -12 km in the horizontal and 35 – 150 m in the vertical) wind measurements in clear as well as partly to sometimes mostly cloudy conditions. Complete profiles from 8-10km flight level to the surface were common.

A summary of the overall DAWN performance within both undisturbed and highly convective conditions during CPEX will be presented. The accuracy, representativeness, and potential bias of the DAWN wind measurements for CPEX and for different convective conditions will be discussed.

A review of the DAWN data processing and the available parameters and data products will be provided. An emphasis will be placed on discussing the evolution of the advanced DAWN data processing software that enables the processing of data in low aerosol/SNR conditions and near the ocean surface.