Projected 21st century changes in snow water equivalent over Northern Hemisphere landmasses from the CMIP5 model ensemble

摘要

Changes in snow water equivalent (SWE) over NorthernHemisphere (NH) landmasses are investigated for the early (2016–2035),middle (2046–2065) and late (2080–2099) 21st century using amulti-model ensemble from 20 global climate models from the Coupled ModelIntercomparison Project Phase 5 (CMIP5). The multi-model ensemble was foundto provide a realistic estimate of observed NH mean winter SWE compared tothe GlobSnow product. The multi-model ensemble projects significantdecreases in SWE over the 21st century for most regions of the NH forrepresentative concentration pathways (RCPs) 2.6, 4.5 and 8.5. This decreaseis particularly evident over the Tibetan Plateau and North America. The onlyregion with projected increases is eastern Siberia. Projected reductions inmean annual SWE exhibit a latitudinal gradient with the largest relativechanges over lower latitudes. SWE is projected to undergo the largestdecreases in the spring period where it is most strongly negativelycorrelated with air temperature. The reduction in snowfall amount fromwarming is shown to be the main contributor to projected changes in SWEduring September to May over the NH.