Monte Carlo Study of UAV-Measurable Albedo over Arctic Sea Ice

• Published in: Journal of Atmospheric and Oceanic Technology
• Main Authors: Podgorny, Igor, Lubin, Dan, Perovich, Donald K.
• Language: unknown
• Published: 2021
• Subjects: 54 ENVIRONMENTAL SCIENCES; Arctic; albedo; Sea ice
• Online Access: http://www.osti.gov/servlets/purl/1541861; https://www.osti.gov/biblio/1541861; https://doi.org/10.1175/jtech-d-17-0066.1

In anticipation that unmanned aerial vehicles (UAVs) will have a useful role in atmospheric energy budget studies over sea ice, a Monte Carlo model is used in this study to investigate three-dimensional radiative transfer over a highly inhomogeneous surface albedo involving open water, sea ice, and melt ponds. The model simulates the spatial variability in 550-nm downwelling irradiance and albedo that a UAV would measure above this surface and underneath an optically thick, horizontally homogeneous cloud. At flight altitudes higher than 100 m above the surface, an airborne radiometer will sample irradiances that are greatly smoothed horizontally as a result of photon multiple reflection. If one is interested in sampling the local energy budget contrasts between specific surface types, then the UAV must fly at a low altitude, typically within 20 m of the surface. Spatial upwelling irradiance variability in larger open water features, on the order of 1000 m wide, will remain apparent as high as 500 m above the surface. To fully investigate the impact of surface feature variability on the energy budget of the lower troposphere ice–ocean system, a UAV needs to fly at a variety of altitudes to determine how individual features contribute to the area-average albedo.