摘要
青藏高原南缘水汽输送和聚散过程决定着高原及其邻域的降水分布特征,在提出"青藏高原南缘水汽输送关键区"(简称南缘关键区)概念的基础上,利用NCEP/NCAR再分析资料分析了1979-2010年南缘关键区夏季水汽输送过程与收支变化,并根据台站降水量观测资料探讨了南缘关键区各边界水汽收支与高原夏季降水分布的关系。结果表明,孟加拉湾偏南风水汽流进入南缘关键区后,在印度热低压与青藏高原大地形制约下,形成了3条进入高原的水汽输送通道。这使得南缘关键区整体为多年平均水汽辐散区,除南边界外,其余均为水汽输出边界。南缘关键区各边界水汽收支年内与年际变化明显,且东、西边界水汽输出强度变化特征相反。而各边界水汽收支与印度热低压和南海夏季风活动关系密切,输出边界的水汽支出异常则直接影响着青藏高原乃至周边季风区的降水异常分布以及极端旱涝事件的发生、发展。此外,NCEP/NCAR与JRA-25再分析资料之间的对比验证表明,这两种再分析资料在青藏高原南缘水汽输送过程的定性研究中是可靠的。
Regional water vapor convergence and divergence over the southern margin of the Qinghai-Xizang Plateau(QXP) can be regarded as a good factor for the formation of rainfall climate and extreme weather in the TP and its surroundings. In view of the key region in southern margin of the QXP(the key region for short),summer moisture transport and budget over the key region are analyzed based on the NCEP / NCAR reanalysis data from 1979 to 2010,combined with rainfall station data as well to explore its effects on the rainfall characteristics in the QXP and its surroundings. The main conclusions are summarized as follow s. Influenced by the Indian low and the terrain of the QXP,three water vapor transport channels were transformed in the key region from the Bay of Bengal moisture flow,and those led to water vapor divergence over the key region where the southern boundary was the only input one. Meanw hile,different boundaries show ed different monthly and interannual variations,especially for the contrary trend of the moisture budget intensity betw een the western and the eastern boundaries. The budget of input and output boundaries were affected by the activities of the Indian low and the South Asian monsoon,and the output boundaries moisture budget was directly connected with abnormal distribution of rainfall and the development of extreme drought and flood events in the QXP and even the monsoon region surroundings. In addition,the reliability of NCEP / NCAR and JRA-25 reanalysis data in qualitative research over the south margin of the QXP was confirmed by comparison of these tow datasets.
出处
《高原气象》
CSCD
北大核心
2015年第2期327-337,共11页
Plateau Meteorology
基金
国家自然科学基金项目(41171062
41471064)
关键词
水汽输送与收支
夏季降水
青藏高原南缘水汽输送关键区
Moisture transport and budget
Summer rainfall
Moisture transport key region in the southern margin of the Qinghai-Xizang Plateau
