Trends in the duration or extent of snow cover are expected to feedback to temperature trends. We analyzed trends in dates of onset and termination of snow cover in relation to temperature over the past 27 years (1980-2006) from over 636 meteorological stations in the Northern Hemisphere. Different trends in snow duration are observed over North America and Eurasia. Over North America, the termination date of snow cover remained stable during the 27 years, whereas over Eurasia it has advanced by 2.6 +/- 5.6 d decade(-1). Earlier snow cover termination is systematically correlated on a year-to-year basis with a positive temperature anomaly during the snowmelt month with a sensitivity of -0.077 degrees C d(-1). These snow feedbacks to air temperature are more important in spring, because high net radiation is coupled with thin snow cover.
- ALBEDO FEEDBACK
- VEGETATION INDEX
[Peng, Shushi; Piao, Shilong] Peking Univ, Coll Urban & Environm Sci, Dept Ecol, Beijing 100871, Peoples R China; [Piao, Shilong] Chinese Acad Sci, Inst Tibetan Plateau Res, Beijing 100085, Peoples R China; [Ciais, Philippe; Wang, Tao] CEA, LCSE, UVSQ, CNRS,UMR, F-91191 Gif Sur Yvette, France; [Friedlingstein, Pierre] Univ Bristol, QUEST, Dept Earth Sci, Bristol BS8 1RJ, Avon, England; [Zhou, Liming] SUNY Albany, Dept Atmospher & Environm Sci, Albany, NY 12222 USA