东亚地区夏季水汽输送特征

利用1950—2002年NCEP/NCAR再分析逐日平均资料，计算全球格点整层水汽输送通量，分析东亚地区夏季水汽输送在推进过程中逐候的气候特征。研究发现：第25—44候是水汽输送变化最为明显的时段，也是水汽输送的集中期；东亚地区各个经度带的偏南风水汽输送在出现时间、北抬进程速度、北界位置、南撤速度等方面均表现出不同的特征；副高边缘的东南风水汽输送具有迂回西扩和快速东撤的特点，并且在强盛期能够到达青藏高原的东南部。

THE CHARACTERISTICS OF EAST-ASIA VAPOR TRANSPORTATION IN SUMMER

With the NCEP/NCAR reanalysis daily average data for 1950-2002, the global transportation fluxes of water vapor are calculated for the whole atmospheric layer, and the climatological characteristics of East-Asia vapor transportation during summer advancement are analyzed. The results reveal that water vapor experiences the most significant and concentrated changes in transportation from the 25~(th) pentad to the 44th pentad; southerly vapor transportation for each of the longitudinal areas in East Asia has different characteristics in appearance time, speed of northward shifts, location of northernmost bound and speed of southward withdrawal; southeasterly vapor transportation at the edge of the subtropical high expands to the west in roundabout ways and withdraws to the east rapidly, and can reach the southeastern tip of the Tibet-Qinghai Plateau during its most vigorous period.