HR: 1330h
AN: C43A-11    [Abstracts]
TI: Radiative Energy Disposition in the Coupled Atmosphere-Snow-Ice-Ocean System
AU: * Stamnes, K
EM: kstamnes@stevens.edu
AF: Stevens Institute og Technology, Castle Point on Hudson, Hoboken, NJ 07030 United States
AU: Hamre, B
EM: borge.hamre@ift.uib.no
AF: University of Bergen Department of Physics and Technology, Allegt 55, Bergen, 5007 Norway
AU: Gerland, S
EM: s.gerland@npolar.no
AF: Norwegian Polar Institute, The Polar Environmental Centre, Tromso, 9296 Norway
AU: Eide, H
EM: heide@stevens.edu
AF: Stevens Institute og Technology, Castle Point on Hudson, Hoboken, NJ 07030 United States
AU: Frette, O
EM: oyvind.frette@ift.uib.no
AF: University of Bergen Department of Physics and Technology, Allegt 55, Bergen, 5007 Norway
AU: Stamnes, J J
EM: jakobj.stamnes@ift.uib.no
AF: University of Bergen Department of Physics and Technology, Allegt 55, Bergen, 5007 Norway
AB: The radiative interaction between the atmosphere and the surface is a factor of paramount importance in the Arctic where the net radiation is the largest component of the surface energy budget. The effect of clouds on the surface energy budget has important implications for the extension of the polar ice cover, which is highly sensitive to the surface irradiance. Also, the cloud cover is very important for the primary production, since it regulates the amount of light available for photosynthesis. Solar radiation affects snow metamorphism, which reduces the surface albedo, leading to further metamorphism (grain growth), increased snow temperature and reduction in snow and ice thicknesses (surface albedo feedback mechanism). Changes in the thickness of snow and sea ice will change the optical properties of the snow and ice system and hence cause a change in the amount of UV radiation and Photosynthetically Available Radiation (PAR) reaching the aquatic environment. Furthermore, a potential increase in ice temperature will change its transparency due to melting and enlargement of brine pockets. Accurate modelling of irradiances in snow and ice requires sophisticated methods. It is very important to take into account the tight radiative coupling between the atmosphere and the snow-sea ice-ocean system, and also the change in refractive index that occurs at the interface between the atmosphere/snow and sea ice/ocean. Such coupling effects may cause the downward irradiance to increase by 75% just beneath the air-ice interface, and the enhancement is much larger under clear sky than under cloudy conditions. A combination of field measurements, state-of-the-art radiative transfer modelling, and satellite data is required to enhance our understanding of the disposition of solar energy in this coupled system. The purpose of this presentation is to outline studies including field measurements and modeling required to quantify cloud-radiation-surface interactions and feedbacks, so as to enhance our understanding of the solar energy disposition in this coupled system, and how it affects climate evolution, and primary production in the polar regions, and the Arctic in particular.
DE: 1640 Remote sensing
DE: 1863 Snow and ice (1827)
DE: 4552 Ocean optics
SC: Cryosphere [C]
MN: 2005 Joint Assembly