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TitleCoupling of winter climate transitions to snow and clouds over the Prairies
AuthorBetts, A K; Desjardins, R; Worth, D; Wang, S; Li, J
SourceJournal of Geophysical Research, Atmospheres vol. 119, issue 3, 2014 p. 1118-1139, https://doi.org/10.1002/2013JD021168
Year2014
Alt SeriesEarth Sciences Sector, Contribution Series 20140250
PublisherWiley-Blackwell
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceAlberta; Manitoba; Saskatchewan
NTS52E; 52L; 52M; 52N; 53D; 53E; 53F/12; 53F/13; 53K; 53L; 53M; 53N; 53O; 54; 62; 63; 64; 72; 73; 74; 82; 83; 84
Lat/Long WENS-120.0000 -89.0000 60.0000 49.0000
Subjectsgeophysics; environmental geology; snow; temperature; climatic fluctuations; climate
Illustrationsplots; tables
ProgramLand Surface Characterization, Remote Sensing Science
Released2014 02 04
AbstractUsing data from 13 climate stations on the Canadian Prairies, together with opaque cloud cover and daily snow depth, to analyze the winter climate transitions with snow, we find that a snow cover acts as a fast climate switch. Surface temperature falls by about 10?K with fresh snowfall and rises by a similar amount with snowmelt, while the daily range of relative humidity falls to around 5–15% with snow cover. These are robust climate signals. For every 10% decrease in days with snow cover over the Canadian Prairies, the mean October to April climate is warmer by about 1.4?K. Stratifying by daily mean opaque cloud cover across snow transitions shows the rapid shift within 5?days from a diurnal cycle dominated by shortwave cloud forcing to one dominated by longwave cloud forcing. We calculate the change in the surface radiative budget with snow using surface albedo data from the Moderate Resolution Imaging Spectroradiometer and station longwave data. We find that with the fall-winter snow transitions, the surface radiative heating is reduced by 50?Wm-2, with 69% coming from the reduced net shortwave flux, resulting from the increased surface albedo and a small increase in effective cloud albedo, and 31% from a reduced incoming longwave flux. This drop in surface radiative heating is sufficient to produce a drop in the surface radiometric skin temperature of 11?K. We find that in winter, the monthly mean diurnal climate is more closely coupled to the diurnal shortwave forcing than the mean diurnal climate.
Summary(Plain Language Summary, not published)
Using data from 13 climate stations throughout the Canadian Prairies, along with cloud cover and daily snow depth, we analyzed the winter climate transitions with snow and found that snow cover acts as an indicator of swift seasonal climate swings. Surface temperature falls by about 10 degrees with fresh snowfall and rises by a similar amount with snowmelt, while the daily range of relative humidity falls to around 5-15% with snow cover. These are robust climate signals. For every 10% decrease in days with snow cover over the Canadian Prairies, the mean October to April climate is warmer by about 1.4 degrees.
GEOSCAN ID295448