Lake-induced snowfall associated with lakes Erie and Ontario in CMIP5 GCMs
Date
2014
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Publisher
University of Delaware
Abstract
In this study, an analysis of simulated lake-induced snowfall from 2006-2100 is conducted, investigating the presence of a lake-induced snowfall signal to the lee of Lakes Erie and Ontario. Output from seven fully coupled global climate models (GCM) s are used from phase five of the Coupled Model Intercomparison Project (CMIP5). Snowfall trends over the entire study area and in the defined lake-induced Snowbelt are examined seasonally for two Representative Concentration Pathway (RCP) scenarios. In addition, physical mechanisms associated with these trends, such as lake lapse rates, surface temperatures and snow to total precipitation ratios are examined. The models perform well when compared to derived and observed snowfall observations despite model difficulties in resolving small scale orographic and finite lake effect processes. Snowfall declines by 20 - 45% over the entire region, with snowfall actually increasing in the lake-induced region during the first quarter century before declining rapidly in RCP 8.5. An additional 1.7 cm snow-water-equivalent (SWE) signal of purely lake-induced snowfall is detected within the ensemble mean of the defined lake-induced Snowbelt to the lee of the two lakes that is not seen in the grid cells outside of the lake belt. Surface two-meter temperature is found to have the most significant impact on snowfall changes in the region, with impacts not on total precipitation, but on the percentage of precipitation falling as snow. Lake lapse rates were found to not provide enough evidence to draw useful conclusions on snowfall trends.