Projections and Physical Drivers of Extreme Precipitation in Greenland & Baffin Bay

Extreme precipitation events can have substantial impacts on communities and the climate system in the warming Arctic, but their changes are not well understood. In this study, the characteristics of extreme precipitation days in the eastern Canadian Arctic and Greenland are examined in historical (1980–1999) and future (2080–2099, SSP5-8.5) variable-resolution Community Earth System Model simulations. Comparisons between the simulations illustrate potential changes in the frequency and intensity of these events in the region. Extreme precipitation is expected to increase broadly across the region. The frequency of the most intense daily precipitation rates is projected to rise, particularly in the northernmost areas. The seasonality of extremes does not shift substantially in the future simulation with most areas receiving the highest accumulations and increases during the summer. However, southeastern Greenland is projected to see decreases in extreme precipitation. Algorithms detecting atmospheric rivers and cyclones are employed to assess how their changes may factor into changes in extreme precipitation. Cyclone frequency remains largely consistent with slight decreases near southeastern Greenland, which may explain decreased extreme precipitation seen in the region. Atmospheric rivers are projected to become more frequent across the domain, largely during the summer. Although the majority of the region's extreme precipitation is associated with cyclones, this suggests that atmospheric rivers become more important in a warming climate. These results provide insight into potential changes in impactful precipitation events in the region and how the processes driving them may change.