伴随着 El Nino 和 La Nina 事件的发生发展，我国东部地区季节降水异常的特征也发生变化。本文通过统计1951-2010年我国东部地区120个站点的月平均降水量资料，利用合成分析的方法，研究中国东部季节降水与 El Nino 和 La Nina 事件的...伴随着 El Nino 和 La Nina 事件的发生发展，我国东部地区季节降水异常的特征也发生变化。本文通过统计1951-2010年我国东部地区120个站点的月平均降水量资料，利用合成分析的方法，研究中国东部季节降水与 El Nino 和 La Nina 事件的关联。结果显示，El Nino 当年冬季和次年春夏季我国东部大部分地区以多雨为主，La Nina 年则相反；长江中下游地区降水显著异常偏多发生在 El Nino 次年春季，且此时长江流域以及河套地区降水量均显著增加，但 La Nina 次年春季该地区雨量无明显变化；El Nino 次年春季和 La Nina 次年夏季西南地区易发生干旱。结果表明 El Nino 和 La Nina 对中国东部季节降水的影响存在非对称性，对于部分地区具有一定的预测意义。展开更多
Based on the CMA tropical cyclone(TC) best track data as well as the reanalysis datasets from the NCEP/NCAR and NOAA, the variation characteristics of TC number from 1949 to 2013 over the western North Pacific(includi...Based on the CMA tropical cyclone(TC) best track data as well as the reanalysis datasets from the NCEP/NCAR and NOAA, the variation characteristics of TC number from 1949 to 2013 over the western North Pacific(including the South China Sea) are examined. Notably, the time series of TC number exhibits a significant abrupt change from more to less around 1995. Comparative analysis indicates that the environmental factors necessary to TC formation also change significantly around the mid-1990 s. After 1995, accompanying with anomalous warm sea surface temperature(SST) in western equatorial Pacific, a La Nia-like pattern in tropical Pacific appears obviously. However,compared with the period before 1995, the vertical upward movement decreases, vertical shear of tropospheric zonal wind increases, and sea level pressure(SLP) rises, all of which are unfavorable to TC formation and work together to make TC number reduce markedly after 1995. Furthermore, when the typical interannual more and less TCs years are selected in the two separate stages before and after 1995, the relative importance of oceanic and atmospheric environments in interannual TC generation is also investigated respectively. The results imply that the SST over the tropical Pacific exerts relatively important influence on TC formation before 1995 whereas the atmospheric circulation plays a more prominent role in the generation of TC after 1995.展开更多
文摘伴随着 El Nino 和 La Nina 事件的发生发展，我国东部地区季节降水异常的特征也发生变化。本文通过统计1951-2010年我国东部地区120个站点的月平均降水量资料，利用合成分析的方法，研究中国东部季节降水与 El Nino 和 La Nina 事件的关联。结果显示，El Nino 当年冬季和次年春夏季我国东部大部分地区以多雨为主，La Nina 年则相反；长江中下游地区降水显著异常偏多发生在 El Nino 次年春季，且此时长江流域以及河套地区降水量均显著增加，但 La Nina 次年春季该地区雨量无明显变化；El Nino 次年春季和 La Nina 次年夏季西南地区易发生干旱。结果表明 El Nino 和 La Nina 对中国东部季节降水的影响存在非对称性，对于部分地区具有一定的预测意义。
基金Key Project of Natural Science Foundation of Yunnan(2016FA041)National Natural Science Foundation of China(41375105)External Cooperation Program of BIC,CAS(GJHZ1729)
文摘Based on the CMA tropical cyclone(TC) best track data as well as the reanalysis datasets from the NCEP/NCAR and NOAA, the variation characteristics of TC number from 1949 to 2013 over the western North Pacific(including the South China Sea) are examined. Notably, the time series of TC number exhibits a significant abrupt change from more to less around 1995. Comparative analysis indicates that the environmental factors necessary to TC formation also change significantly around the mid-1990 s. After 1995, accompanying with anomalous warm sea surface temperature(SST) in western equatorial Pacific, a La Nia-like pattern in tropical Pacific appears obviously. However,compared with the period before 1995, the vertical upward movement decreases, vertical shear of tropospheric zonal wind increases, and sea level pressure(SLP) rises, all of which are unfavorable to TC formation and work together to make TC number reduce markedly after 1995. Furthermore, when the typical interannual more and less TCs years are selected in the two separate stages before and after 1995, the relative importance of oceanic and atmospheric environments in interannual TC generation is also investigated respectively. The results imply that the SST over the tropical Pacific exerts relatively important influence on TC formation before 1995 whereas the atmospheric circulation plays a more prominent role in the generation of TC after 1995.
