资源环境科技发展态势分析平台

Climate change may accelerate the water cycle on the global scale, resulting in more frequent extreme climate events. However, very few studies are available on the effect of global warming on winter extreme precipitation and its causes. In this investigation, the effect of global warming on winter extreme precipitation in the high-latitude regions of Northeast China and the changes in large-scale circulation patterns are studied using the data recorded by 62 meteorological stations in Heilongjiang Province from 1961 to 2018, along with daily NCEP/NCAR reanalysis data. The results reveal an abrupt change in the winter temperature of Heilongjiang Province in 1986, and the onset of a period of relatively warm winters during which a temperature rise of 1.7 °C was discovered. The winter precipitation increased by 5.4 mm during the warm period, which is a significant change from that in the cold period, and included an abrupt change in precipitation in 1995. 75% of the years with extreme precipitation and 100% of the years with high-extreme precipitation occurred during the warm period. The interannual variability of precipitation in the warm period was large. During the warm period, changes were observed in the Arctic polar vortex, the East Asian trough, and the circulation at 850 hPa. The strength of the Arctic polar vortex decreased significantly at a rate of 56.2 hPa/10a, with an abrupt change occurring in 2002. The strength of the East Asian trough decreased noticeably by 6.8 hPa during the warm period, and was located 40 degrees west longitudinally compared to the cold period. These changes led to weakened downdrafts and enhanced updrafts, and an increased warm, humid air current flowing over Heilongjiang Province in winter. More cold air and warm humid air currents converged above this region due to changes in the circulation at 850 hPa, increasing winter precipitation. The greater interannual variability of the strength of the Arctic polar vortex and East Asian trough during the warm period increased the number of years with winter extreme precipitation in the province, and resulted in larger precipitation variability. The changes in the large-scale atmospheric circulation pattern are attributed to the temperature rise in the Arctic and its surrounding high-latitude areas.