HR: 0800h
AN: C31A-0294    [Abstracts]
TI: Long-wave Irradiance Measurement and Modeling during Snowmelt, a Case Study in the Yukon Territory, Canada
AU: Sicart, J
EM: jms@aber.ac.uk
AF: Centre for Glaciology, Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, SY233DB United Kingdom
AU: * Essery, R
EM: rie@aber.ac.uk
AF: Centre for Glaciology, Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, SY233DB United Kingdom
AU: Pomeroy, J
EM: pomeroy@usask.ca
AF: Centre for Hydrology, Dept. of Geography, 42 Kirk Hall, University of Saskatchewan, 117 Science Place, Saskatoon, S7N 5C8 Canada
AB: At high latitudes, long-wave radiation emitted by the atmosphere and solar radiation can provide similar amounts of energy for snowmelt due to the low solar elevation and the high albedo of snow. This paper investigates temporal and spatial variations of long-wave irradiance at the snow surface in an open sub-Arctic environment. Measurements were conducted in the Wolf Creek Research Basin, Yukon Territory, Canada (60ø36'N, 134ø57'W) during the springs of 2002, 2003 and 2004. The main causes of temporal variability are air temperature and cloud cover, especially in the beginning of the melting period when the atmosphere is still cold. Spatial variability was investigated through a sensitivity study to sky view factors and to temperatures of surrounding terrain. The formula of Brutsaert gives a useful estimation of the clear-sky irradiance at hourly time steps. Emission by clouds was parameterized at the daily time scale from the atmospheric attenuation of solar radiation. The inclusion of air temperature variability does not much improve the calculation of cloud emission.
DE: 1863 Snow and ice (1827)
DE: 1878 Water/energy interactions
DE: 1610 Atmosphere (0315, 0325)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting