Observations of Marine Atmospheric Boundary Layer Processes and High-Frequency Internal Waves from Ship-Launched UAVs and Ship-based Instrumentation

Thursday, 18 December 2014: 4:30 PM
Ben D Reineman1, Luc Lenain2 and Wallace Kendall Melville2, (1)Scripps Institution of Oceanography, La Jolla, CA, United States, (2)University of California San Diego, La Jolla, CA, United States
We present measurements obtained during the October 2012 EquatorMix experiment (0N, 140W), in which we deployed ship-launched and recovered Boeing-Insitu ScanEagle unmanned aerial vehicles (UAVs) to measure momentum and energy fluxes, ocean surface processes, and the marine atmospheric boundary layer (MABL). The UAV dataset is complemented by measurements from a suite of ship-based instrumentation, including a foremast MABL eddy covariance system, scanning and point lidar altimeters, a laser Doppler wind profiler, and a digitized X-band radar system (WaMoS). The combination of the unmanned aircraft and the ship instrumentation provides a novel and valuable dataset of many air-sea interaction phenomena, extending from 100s of meters below the surface to 1500 m above. Ocean surface displacements observed with the UAV lidar altimeter (coupled with a GPS/IMU) give evidence of high-frequency equatorial internal waves, with measurements consistent and coherent with those from ship-based X-band radar, the Hydrographic Doppler Sonar System (HDSS), and a theoretical model. UAV-based flux measurements at low altitudes (down to 30 meters) are consistent with ship-based eddy covariance measurements, but reveal differences between along- and crosswind sampling flight legs associated with longitudinal roll structures that are not captured by the ship measurements from tracks mainly in the upwind-downwind directions.