热带大气季节内振荡与2008年初中国南方雪灾的关系

利用热带大气季节内振荡(MJO)指数、向外长波辐射(OLR)资料和NCEP/NCAR全球逐日再分析资料以及中国南方地区降水资料，应用合成分析等探讨了MJO与2008年初南方雪灾的关系，进而从MJO角度研究雪灾过程成因。结果表明：雪灾过程中，MJO存在明显的东传现象，即由西太平洋向东传送至印度洋附近。伴随着MJO的向东传播，中国南方降水强度及集中区也在随之变化，MJO在一定程度上对雪灾过程有调制作用。通过对OLR的分析，表明2008年初中国南方4次异常降水(雪)过程受到了MJO两次东传的影响，第一次导致西太平洋副热带高压持续偏强，第二次导致南支槽活跃；副热带高压西侧偏南风带来的暖湿气流，以及南支槽带来的印度洋和孟加拉湾的暖湿气流不断向中国输送，为中国南方强降水过程提供了水汽条件。

The relationship between MJO and snow disaster in the south of China in January of 2008

Based on the Madden-Julian oscillation index, the outgoing long wave radiation （OLR） data, the daily NCEP/NCAR reanalysis data and precipitation data in the south of China, the relationship between Madden-Julian oscillation（MJO） and the snow disaster in 2008 in the south of China and the forming reason of snow disaster were discussed by a synthetic analysis method. The results show that the MJO has an obviously eastward phenomenon in the snow disaster process, namely, it spreads from the Western Pacific to the India Ocean. Accompanying with the eastward MJO,the precipitation intensity and its concentrating region also change. The MJO could modulate the snow disaster process to some extent. The analysis of OLR also suggests that four abnormal rainfall（snow） proces- ses in the early of 2008 in the south of China are influenced by the two eastward MJO. The first eastward MJO leads to the strength of the western Pacific subtropical high continually, while the second one makes the south branch trough active. The southward wind in the west side of subtropical high and the active of the south branch trough make the warm wet airflow transporting continually to China, which provides water vapor condition for strong precipitation in the south of China.