CPEX 2017: Utilizing the Airborne Doppler Aerosol WiNd Lidar and Dropsondes for Convective Process Studies

During 25 May – 24 June 2017, NASA sponsored and conducted the airborne 2017 Convective Processes in the Tropics Experiment (CPEX) which utilized the Doppler Aerosol WiNd lidar (DAWN), dropsondes and other remote sensing instruments aboard a NASA DC-8 aircraft with the objective to study and improve our understanding and modeling of convective processes in the tropics. Based out of Fort Lauderdale, FL, the NASA DC-8 flew a total of sixteen airborne missions into the Gulf of Mexico, Caribbean Sea and the Atlantic Ocean which enabled a comprehensive set of observations (particularly winds from DAWN and the dropsondes) 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 with a laser that pulses at 2-micron wavelength/10 Hz and previously participated in NASA GRIP (2010) and Polar Winds (2014-15) airborne campaigns. The dropsondes and system used during CPEX 2017 were the High Definition Sounding System (HDSS) dropsonde delivery system developed by Yankee Environmental Services (YES) which had previously been used during NASA Polar Winds 2014-15 and GRIP.

The main purpose of this presentations is to provide a comparison of wind speed and wind direction measurements taken by the newer DAWN lidar and the more conventional dropsondes provided by YES. Initial analysis of DAWN data has shown excellent vertical coverage and agreement with dropsonde winds but a more detailed comparative study will be presented.

In addition to the DAWN-dropsonde comparison, we will also give an overview of the performance of DAWN and utility of the DAWN wind data for various convective and non-convective cases. This will include the utilization of the high resolution (5 -12 km in the horizontal and 75 – 150 m in the vertical) DAWN data to conduct divergence and budget calculations over selected convective or non-convective areas or boxes (100 km²) in the tropics.