Trends And Variability In Rain-on-Snow Events.pdf

- Frequency and Location: Rain-on-snow (ROS) events are rare outside specific regions like western Eurasia, western North America, northeastern US, and southeastern Canada. They occur at high latitudes, away from continental interiors.
- Trends: No robust trends were found in the frequency of ROS events.
- Variability: ROS events vary with the Arctic Oscillation/North Atlantic Oscillation (AO/NAO). A northeast/southwest dipole feature across western Eurasia is notable. More ROS events occur in northeastern Europe during positive AO/NAO phase due to increased rainfall, and in Central Europe during negative phase due to increased snow cover.
- Impacts: ROS events constrain surface soil temperatures near 0°C, accelerate snow melting, and can lead to drier soils in summer. They have significant consequences in permafrost regions and where foraging animals and ungulates live.
- Climate Change: Warmer winters bring more rain than snow, increasing moisture in soil and runoff. In the Arctic, more ROS events are possible with increased precipitation in fall and spring. The area affected by ROS events is expected to increase by 40% by the 2080s over Northern Eurasia.
- Large-Scale Characteristics: The study analyzes hemispheric patterns, trends, and relationships of ROS events with large-scale climate modes to anticipate future changes with climate change.