Arctic Atmospheric Boundary Layer Regimes Observed using Unmanned Aircraft Systems (UAS) during the MOSAiC Expedition

Transfer of energy between the Earth's surface and the overlying atmosphere, particularly at high latitudes, remains an area of substantial uncertainty in our understanding of the global climate system. To reduce this uncertainty, unmanned aircraft-based observations of the lower atmosphere were made over Arctic sea ice during legs 3 and 4 (March through August 2020) of the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) Expedition. Specifically, meteorological data throughout the lowest 1km of the atmosphere were gathered with the University of Colorado DataHawk2, a small fixed-wing unmanned aircraft with a 40-min endurance time, equipped with multiple sensors for measuring air pressure, temperature and humidity, wind speed and direction, infrared brightness temperatures of the sky and surface, and turbulence. These measurements provide unprecedented perspectives on lower atmospheric state over the central Arctic from late winter through summer.

In this presentation, we will provide a brief overview of the MOSAiC UAS flights, as well as an analysis of atmospheric profiles sampled. For each flight, we categorize the stability regime and identify the boundary layer height, comparing a subjective boundary layer height with objective boundary layer heights from several published methods. Lastly, we relate boundary layer stability and height to other features within the profile including low-level jets and inversions.