## 5 Conclusions  
As a key part of the global climate system, arctic precipitation is of great significance in studying arctic climate change. In this study, we applied the monthly average sea ice concentration data and monthly average reanalysis data to analyze winter precipitation anomalies in the BKS from 1988 to 2017, finding that precipitation in the BKS has been on the rise for 30 years. Through the correlation analysis, we found that the increase of the sea's winter precipitation was closely related to the decrease of autumn eastern Siberian Sea ice conditions. The September eastern Siberian Sea ice extent has the strongest impact on the precipitation in the Barents and Kara Seas in the winter. We specially analyzed the Sep-Oct eastern Siberian Sea ice anomaly as the sea ice index. By calculating the relationship between the autumn sea ice index and the characteristics of the main atmospheric circulation in the northern hemisphere, we found that the autumn sea ice anomaly in the eastern Siberian Sea was related to winter SH (R = 0.5). We also calculated the relationship between SH and arctic precipitation, indicating that the winter SH is closely related to the winter BKS precipitation. When the eastern Siberian Sea ice extent decreased in autumn, a significant positive geopotential height anomaly occurred in Norway-Barents in winter, which in turn led to positive atmospheric circulation in the Atlantic Ocean. According to our analysis, the eastern Siberian Sea ice extent decreased in autumn. This decrease preceded a significantly positive geopotential height anomaly over the Norway-Barents (NB) Seas in winter. Following this increase were changes in atmospheric circulation, including a southerly wind anomaly that flows from the mid-latitudes of the North Atlantic, across the Greenland Sea, and toward the North Pole. These winds carry warm, humid air. Simultaneously, an anomalously strong northerly wind blows across the Barents and Kara Seas, eastwardly transporting the moistened air transported from the mid-Atlantic. This results in an increase in both the local precipitation and surface air temperatures of the BKS region. By calculating the water vapor transport in the low sea ice index years, we found that a positive northward water vapor transportation exists in the Atlantic Ocean. This result is very similar to that of the anomalous wind field in the low sea ice index. In the high sea ice index years, southerly winds in the Atlantic were suppressed, preventing an increase in arctic precipitation. Thus, the strong water vapor transport in the Atlantic Ocean to the North Pole disappeared, and it only reached Norway and spread southward. The BKS ice evaporation is an important factor, as is water vapor transport. The increase of the meridional water vapor caused an increase in the air temperature near the Barents and Kara Sea. Figure 11: The correlation coefficient between the autumn eastern Siberian Sea ice extent and the winter air temperature at 2 m.  
We calculated the relationship between the air temperature anomaly near said sea and the precipitation and potential evaporation. The correlation coefficients were 0.55 and 0.87, respectively. In this case, a strong positive relationship exists between evaporation of the arctic surface and local precipitation. The low sea ice index years featured the positive anomalous distribution of OLR in the anomalous precipitation area, which indicates that the local convective activity leads strongly to the bolstering of local precipitation. Meanwhile, in high sea ice index years, the negative anomaly distribution of OLR in the area of precipitation anomaly inhibited convective activity, which is not conducive to precipitation. This further proves that surface evaporation will lead to increased precipitation. More research work is still needed to refine this issue in future studies. Conceptualization, J.F. and Y.Z. ; methodology, Y.Z. ; software, J.F. ; validation, J.F., C.K., and Y.Z. ; formal analysis, J.F. ; investigation, C.K. ; resources, C.K. ; data curation, J.F.