Unmanned aerial systems measurements in the Arctic during the MOSAiC campaign: Observations of the boundary layer and surface albedo during the melting season

Abstract:

Unmanned aerial systems (UAS) were part of the MOSAiC expedition (Multidisciplinary drifting Observatory for the Study of Arctic Climate). The University of Colorado, Boulder, deployed several types of UAS during Leg 4 of the campaign, which took place during the melting season of the Arctic sea ice (June-August 2020). Detailed profiles up to 1000 m. asl on the vertical structure of lower atmospheric thermodynamic (pressure, temperature, humidity) and dynamic (wind) characteristics were provided by a fixed-wing UAS (Datahawk). Spatial variability and surface properties such as albedo and sea ice fraction were additionally measured with a copter UAS (HELiX). Based on the measurements collected during Leg 4, two case studies will be introduced to describe conditions of the boundary layer encountered during the melting season. The first case study will focus on clear sky days with a stable boundary layer capped by a strong inversion. The second case will present meteorological conditions observed during cloudy days with warm airmasses measured above the inversion. Radiation measurements from copter UAS occurred simultaneously with profiling from a tethered balloon and ground measurements set up on a sled on the sea ice. The different platforms provide complementary measurements to better understand the processes driving the energy transfer between the surface and the overlying atmosphere.