冬季西太平洋和海洋性大陆热源变化特征及其影响

利用ERA-interim再分析资料、中国地面降水资料、全球海温(SST)和降水资料研究了冬季西太平洋和海洋性大陆大气热源变化特征及其对区域气候的影响。结果表明:冬季西太平洋和海洋性大陆热源具有显著的年际变化，海洋性大陆热源同时存在明显的年代际变化。冬季西太平洋热源强年相较弱年，东亚副热带急流轴线偏北3~4 °，东亚冬季风显著加强；热源强度与中国东部大部分地区冬春季降水呈显著负相关。由于西太平洋热源与ENSO事件密切相关，去除ENSO影响后，西太平洋热源对急流和冬季风的影响明显减弱，且与华东南部和华南地区降水无显著相关，但仍与华东中北部和华北地区呈显著负相关，相关关系仍可从同期冬季持续到后期春季。海洋性大陆热源在1993年左右发生显著突变，突变后海洋性大陆附近SST显著升高，海平面气压显著降低。进一步分析表明，海洋性大陆地区大气热源与Walker环流在年代际尺度上存在很好的对应关系，海洋性大陆岛屿整体增暖趋势快于周围海洋，导致海陆热力差异增大，这可能是触发局地热源和Walker环流长期变化的主要原因，进而影响太平洋SST分布和全球增暖的进程。 

SPATIOTEMPORAL CHARACTERISTICS OF ATMOSPHERIC HEAT SOURCE OVER THE WESTERN PACIFIC AND MARITIME CONTINENT IN WINTER SEASON AND THEIR IMPACT

ERA-interim reanalysis, Chinese precipitation, global sea surface temperature (SST) and precipitation datasets are used to study the spatiotemporal variation of heat sources over the western Pacific (WP) - Maritime Continent (MC) in winter and their impacts on regional climate. Results indicate that both WP and MC heat sources in winter exhibit significant interannual variations while the MC heat source also has a profound inter-decadal variation. The East Asian winter subtropical jet stream (EASJS) is closely related to the WP heat source with its axis shifting northward by 3-4° in strong heat source years in comparison with weak heat source years, together with a stronger East Asian winter monsoon (EAWM). The WC heat source also has a marked negative correlation with precipitation over most areas of east China both in winter and the following spring. Due to the high correlation between the WP heat source and ENSO, the WP heat source still has a marked impact on precipitation north of China, EASJS, and EAWM both in winter and the following spring when the ENSO signal is removed. The MC heat source experiences an abrupt change around 1993 with much warmer SST and lower sea level pressure (SLP) after the year. Further analysis shows that the MC source is closely related to the Walker circulation both on inter-annual and inter-decadal time scales, and the fact that the warming trend over MC islands is much higher than their surrounding oceans after 1993 leads to a larger sea-land thermal difference, which may trigger the long-term change in local heat source and Walker circulation, thus, playing a major role in affecting the SST distribution over the eastern Pacific and even the global warming stagnation.