Title Large surface radiative forcing from topographic blowing snow residuals measured in the High Arctic at Eureka
Author Lesins, G.; Bourdages, L.; Duck, T.J.; Drummond, J.R.; Eloranta, E.W.; Walden, V.P.
Author Affil Lesins, G., Dalhousie University, Department of Physics and Atmospheric Science, Halifax, NS, Canada. Other: University of Wisconsin; University of Idaho
Source Atmospheric Chemistry and Physics, 9(6), p.1847-1862, . Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1680- 7316
Publication Date 2009
Notes In English. Published in Atmospheric Chemistry and Physics Discussions: 29 September 2008, http://www.atmos-chem-phys- discuss.net/8/17691/2008/acpd-8-17691-2008.ht ml; accessed in Apr., 2011. 27 refs. GeoRef Acc. No: 310588
Index Terms aerosols; precipitation (meteorology); backscattering; boundary layer; climate; crystals; humidity; ice; ice crystals; lasers; lidar; optical properties; radar; snow; solar radiation; spectra; temperature; Arctic region; Canada--Nunavut--Eureka; atmospheric precipitation; atmospheric transport; Canada; climate forcing; Eureka Nunavut; infrared spectra; laser methods; lidar methods; MODIS; Nunavut; radar methods; solar forcing; transport; winds
Abstract Ice crystals, also known as diamond dust, are suspended in the boundary layer air under clear sky conditions during most of the Arctic winter in Northern Canada. Occasionally ice crystal events can produce significantly thick layers with optical depths in excess of 2.0 even in the absence of liquid water clouds. Four case studies of high optical depth ice crystal events at Eureka in the Nunavut Territory of Canada during the winter of 2006/07 are presented. They show that the measured ice crystal surface infrared downward radiative forcing ranged from 8 to 36 W m-2 in the wavelength band from 5.6 to 20 Ám for 532 nm optical depths ranging from 0.2 to 1.7. MODIS infrared and visible images and the operational radiosonde wind profile were used to show that these high optical depth events were caused by surface snow being blown off 600 to 800 m high mountain ridges about 20 to 30 km North-West of Eureka and advected by the winds towards Eureka as they settled towards the ground within the highly stable boundary layer. This work presents the first study that demonstrates the important role that surrounding topography plays in determining the occurrence of high optical depth ice crystal events from residual blowing snow that becomes a source of boundary layer ice crystals distinct from the classical diamond dust phenomenon.
URL http://www.atmos-chem-phys.net/9/1847/2009/acp-9-1847-2009.pdf
Publication Type journal article
Record ID 65007013