Measurements and modeling of optical-equivalent snow grain sizes under arctic low-sun conditions

Autor: J��kel, E., Carlsen, T., Ehrlich, A., Wendisch, M., Sch��fer, M., Rosenburg, S., Nakoudi, K., Zanatta, M., Birnbaum, G., Helm, V., Herber, A., Istomina, L., Mei, L., Rohde, A.
Jazyk: angličtina
Předmět:
Popis: The size and shape of snow grains directly impacts the reflection by a snowpack. In this article, different approaches to retrieve the optical-equivalent snow grain size (r$_{opt}$) or, alternatively, the specific surface area (SSA) using satellite, airborne, and ground-based observations are compared and used to evaluate ICON-ART (ICOsahedral Nonhydrostatic���Aerosols and Reactive Trace gases) simulations. The retrieval methods are based on optical measurements and rely on the r$_{opt}$-dependent absorption of solar radiation in snow. The measurement data were taken during a three-week campaign that was conducted in the North of Greenland in March/April 2018, such that the retrieval methods and radiation measurements are affected by enhanced uncertainties under these low-Sun conditions. An adjusted airborne retrieval method is applied which uses the albedo at 1700 nm wavelength and combines an atmospheric and snow radiative transfer model to account for the direct-to-global fraction of the solar radiation incident on the snow. From this approach, we achieved a significantly improved uncertainty (
Databáze: OpenAIRE