Multi-Frequency Radar Observations of Tropical Oceanic Convection during CPEX-CV

Tropical oceanic convection has long been a focus of field campaigns that have delivered valuable observations of the 3-D structure and lifecycle of convection. From the early days of the GATE experiment, revealing the important role of stratiform precipitation, to 2006’s NAMMA experiment highlighting flow structures within mesoscale convective systems (MCSs) moving offshore, radar has provided new insights into convective systems off the west coast of Africa where African Easterly Waves (AEWs), Saharan Dust (SAL), and the Intertropical Convergence Zone (ITCZ) exert significant influence. The recent NASA Convective Processes Experiment - Cabo Verde (CPEX-CV), occurring September 2022, continued this legacy of using the latest radar technology to advance a process-level understanding of convection in this region. Unique to the overall CPEX campaign series was an airborne payload including a multi-frequency Doppler radar and a Doppler Aerosol WiNd Lidar (DAWN), to obtain highly detailed wind observations in the vicinity of the convection. CPEX-CV in particular included the Airborne Precipitation Radar (APR-3), providing simultaneous Doppler observations of convective systems at Ku-, Ka-, and W-band frequencies, allowing for hydrometeor inferences to be made in the context of Doppler winds internal to the storms and in context of surrounding near-storm winds from DAWN.

During the CPEX-CV campaign, the DC-8 aircraft flew 13 research missions, encompassing a range of convective types (i.e., isolated and those organized on the mesoscale) associated with different large-scale influences (i.e., AEW, SAL, ITCZ) to provide a robust dataset for describing convective characteristics in a new way in this region. These flights included multiple passes through the same evolving convective system, such as Research Flight 7 where APR-3 captured the early stages of an intensifying MCS with high liquid water content and lightning. Embedded deep convection within stratiform was the norm, different from the fast-moving squall lines that were captured moving off the coast during NAMMA. This presentation synthesizes the characteristics of convection observed by radar during CPEX-CV, including 3-D structure, intensity, and hydrometeor inferences. Results are placed in the context of satellite-based tracked convection to determine where within the overall lifecycle these storms were sampled.