Strengthened relationship between sea ice in East Siberian Sea and midsummer rainfall in Northeast China

Abstract

Arctic sea ice displays the high rates of decay during summer-autumn. Previous studies have revealed the impact of autumn Arctic sea ice on local and remote atmospheric circulation. Few attentions have been paid on the relationship between summer Arctic sea ice and climate variation at Eurasia. This study identifies a strengthened relationship between midsummer rainfall at Northeast China (NEC) and simultaneous sea ice area (SIA) in East Siberian Sea after the 1990s. The NEC’s rainfall shows a significant positive correlation with the SIA during 1994–2016, whereas the relationship is insignificant during 1961–1983. The strengthening of the relationship is attributed to the western elongation of background circulation at the North Pacific and the increased interannual variability of the SIA after the 1990s. The former facilitates the western extension of the SIAI-associated circulation over the Central North Pacific. The enlarged amplitudes of sea ice induce surface heat fluxes in situ, and then it leads to stronger meridional temperature gradient anomalies and intensified interaction between synoptic-scale eddies and mean flow over the North Pacific. These conditions jointly contribute to stronger and western elongation of circulation over the Central North Pacific during 1994–2016. Accordingly, the SIA has an intimate connection with NEC’s rainfall though the modulation of moisture transport and vertical movement.