Arctic Climate Feedbacks in ERA5 Reanalysis: Seasonal and Spatial Variations and the Impact of Sea-Ice Loss

Radiative climate feedbacks in the Arctic have been extensively studied, but their spatial and seasonal variations have not been thoroughly examined. Using ERA5 reanalysis data, we examine seasonal variations in Arctic climate feedbacks and their relationship to sea-ice loss based on changes from 1950-1979 to 1990-2019. The spring and summer seasons experienced large sea-ice loss, strong surface albedo feedback, and large oceanic heat uptake. Arctic clouds exerted small net cooling in May-June-July but moderate warming during the cold season, especially over areas with large sea-ice loss where cloud liquid and ice water content increased. Arctic water vapor feedback peaked in summer but was weak and uncorrelated with sea-ice loss. Arctic positive lapse rate feedback (LRF) was strongest in winter over areas with large sea-ice loss and weak inversion but uncorrelated with atmospheric stability, suggesting that oceanic heating from sea-ice loss led to enhanced surface warming and the positive LRF.

Automated summary

In this study, seasonal variations in Arctic climate feedbacks and their relationship to sea-ice loss were investigated using ERA5 reanalysis data. The results showed that spring and summer experienced significant sea-ice loss, strong surface albedo feedback, and large oceanic heat uptake. Arctic clouds had a small net cooling effect in May-June-July but a moderate warming effect during the cold season, particularly in areas with substantial sea-ice loss. Arctic water vapor feedback reached its peak in summer but was weak and unrelated to sea-ice loss. Arctic positive lapse rate feedback (LRF) was strongest in winter over regions with significant sea-ice loss and weak inversion but was uncorrelated with atmospheric stability, indicating that oceanic heating from sea-ice loss led to enhanced surface warming and positive LRF.