资源环境科技发展态势分析平台

Based on the daily precipitation data from 208 meteorological stations in Northeast China, NCEP/NCAR re-analysis monthly mean wind, sea level pressure data and NOAA reconstructed monthly mean sea surface temperature (SST) data from 1961 to 2013, the contribution rate of heavy rainfall to the total rainfall (hereafter referred to as "heavy rainfall contribution rate" or HRCR) during the rainy season in Northeast China was investigated. The changing characteristics of HRCR in the context of global warming are analyzed. The relationship between the HRCR and the contemporaneous atmospheric general circulation and early SST anomaly was analyzed to understand the possible physical mechanism responsible for the changing HRCR before and after the warming. Results show that during the whole study period (1961-2013), no evident trend in the HRCR has been detected. However, during cold period (1961-1979), the HRCR showed a significantly declining trend, while during warm period (1981-2013), the HRCR does not exhibit any trend. During cold period, the anomalous North Pacific summer monsoon and March North Atlantic tripole SSTA are the main factors affecting the HRCR, while the West Pacific summer monsoon, the East Asian subtropical westerly jet and March North Pacific dipole SSTA are responsible for the HRCR in the warm period. In the cold period, due to the air-sea interaction, March Atlantic tripole SSTA can influence the North Pacific summer monsoon in the late July August, in turn affecting the HRCR. In the warm period, March North Pacific dipole SSTA tends to cause anomalies in the West Pacific summer monsoon and the position of the East Asian subtropical westerly jet axis in the July August through air-sea interaction, thereby affecting the HRCR. During 1961-1979, the weakening of the North Pacific summer monsoon might have been the primary cause of the significant decline in the trend of the HRCR in the cold period. In 1981-2013, the absence of significant trends of the West Pacific summer monsoon and subtropical westerly jet position might be the main reason for the lack of an obvious linear trend of HRCR in the warm period.