Future projections of wet snow accretion and snowfall in Kanto Plain, Japan, using a large ensemble climate simulation

Snowfall and wet snow accretion in the Kanto Plain, including the Tokyo Metropolitan Area, significantly impact the lives of people there. This study used a large ensemble simulation to predict future changes in the frequency of snowfall and wet snow accretion, and the accumulated snowfall and wet snow accretion during an event. We assessed wet snow accretion using a model that considers the effects of temperature, precipitation, wind speed, and humidity. The future snowfall event frequency and accumulated snowfall were predicted to decrease by 0.73 year-1 (61%) and 0.69 mm (11%), respectively, under +2-K future climate projections from those under the present climate. 87% and 13% reduction in future snowfall events was due to increasing temperature and reduced frequency of extratropical cyclone passages, respectively. Moreover, the future frequency of wet snow accretion events and accumulated wet snow accretion are predicted to decrease by 0.84 year-1 (90%) and 0.73 kg m-1 (29%), respectively, from those in the present. 91% and 9% reduction in future wet snow accretion events was due to increasing temperature and reduced frequency of extratropical cyclone passages, respectively. Snowfall and wet snow accretion risk are predicted to decline under the +2-K future climate projections from those under the current climate. The risk can decrease more significantly in the coastal areas than in the inland areas. We hope that the information provided in this study will help policymakers of local governments in the Kanto Plain to implement appropriate measures against future snowfall and wet snow accretion. We reveal future changes in wet-snow accretion and snowfall in and around the Tokyo Metropolitan Area by assessing the impact of temperature increments and future changes in cyclones. Wet-snow accretion and snowfall risk will dramatically decline in the mid-21st century from the current level, predominantly due to temperature increments.image