Winter rain on snow and its association with air temperature in northern Eurasia

This study examines the characteristics of winter (Dec-Feb) rain-on-snow events and their relationship to surface air temperatures to reveal potential changes in rain-on-snow days under a warming climate over northern Eurasia. We found that rain-on-snow events mostly occur over European Russia during winter. Rain-on-snow days increase as air temperature increases and are primarily attributable to the increase in rainfall days. Air temperature is the primary cause for these changes, while the North Atlantic Oscillation has some influence on the rain on snow and rainfall over the northern part of European Russia. The magnitude of rain-on-snow increase ranges from 0.5 day to 2.5 days per degree Celsius increase in air temperature. Higher rates of increase in rain-on-snow days occur in the northern and eastern parts of European Russia where the air temperature is lower, in contrast to rainfall days which have higher rates at locations with higher air temperatures. This suggests that a decrease in snowfall days might be limiting the rate of increase in rain-on-snow events over warmer regions where the temperature is about -8 degrees C or higher. This study also implies that rain-on-snow days will become more common over regions in which it is currently a rare event as air temperatures increase. Copyright (c) 2008 John Wiley & Sons, Ltd.