Response of daily snowfall extremes to climate change: theory and simulations

Abstract:

Snowfall is sensitive to climate change through changes in air temperature, humidity, and dynamics. Because of the sensitivity to temperature, annual-mean snowfall is expected to decrease in a warming climate except in very cold regions. However, it is shown here that CMIP5 models simulate smaller fractional changes in the intensities of daily snowfall extremes than in mean snowfall for many regions and months of the year. An asymptotic theory is introduced for snowfall extremes based on the temperature dependencies of the rain-snow transition and precipitation extremes. The theory accounts for the main features of the response of snowfall extremes to warming in the simulations. A variant of the theory that better accounts for the role of dynamics will also be discussed.