Cold Season Cloud Response to Sea Ice Loss in the Arctic

Abstract Based on satellite observations, we investigate the cloud responses during the cold season, from October to the following March, to interannual fluctuations in Arctic sea ice concentrations during September and October. It is found that the cloud responses differ between the periods 2000–18 and 1982–99. From 2000 to 2018, increased Arctic Ocean cloud cover in October and November transitioned to significantly less cloud cover and cloud radiative forcing (CRF), from January to March, in response to lower sea ice concentrations in September and October. The lower CRF from January to March preconditions the sea ice and likely contributes to higher sea ice concentrations the following September. This suggests a negative cloud feedback on sea ice concentration, which may contribute to sea ice recovery after a dramatic decrease. In contrast, from 1982 to 1999, generally increased cloud cover and cloud radiative forcing persisted from October to March following lower sea ice concentrations in the preceding September and October. The cause of the different cloud responses to sea ice changes in these two time periods remains unclear and requires further investigation.