Strengthening influence of atmospheric rivers on global snow depth dynamics.

Abstract

Atmospheric rivers (ARs), narrow zones of intense water vapor transport in the Earth's atmosphere, play a pivotal role in driving heavy precipitation and temperature anomalies. Snowpack dynamics, essential for global water availability, are sensitive to variations in precipitation and temperature. However, the global influence of ARs on snowpack dynamics remains unclear. Here, we assess how ARs affect snow depth worldwide and explore the underlying physical mechanisms. Our results reveal that ARs drive strong intra-seasonal snowpack variability-generally increasing snow depth in winter and spring and decreasing it in summer (with declines exceeding 15% in Temperate regions) and autumn. Active El Niño-Southern Oscillation can amplify this influence. On interannual timescales, more frequent ARs are associated with reduced snow depth in summer but increased snow depth in other seasons. Snowfall emerges as the primary factor explaining interannual snowpack changes related to ARs. This study provides a crucial advancement in understanding the complex climate-snowpack relationship and underscores the need to represent AR-snowpack interactions in Earth system models.