近50a春季东亚温带气旋活动频数的气候特征及其变化

Climatic Characteristics of Extratropical Cyclone Frequency and Its Variations over East Asia during Recent 50 Years in Spring

根据 194 8— 2 0 0 0年共 5 3a的 NCEP/ NCAR逐日海平面气压再分析资料 ,分析了春季 (3、4、5月 )东亚内陆和沿海地区气旋活动频数、气旋移动路径等气候特征及其年际、年代际变化 ,结果表明在春季的 3、4、5月份中 ,内陆存在三个明显的气旋活动频数较大的地区 ,分别位于 10 1°E、4 5°N附近的蒙古高压南缘、贝加尔湖以东的 115°E、5 3°N附近地区和 12 6°E、5 3°N我国东北北部附近地区。蒙古地区春季气旋活动频数存在明显的年代际变化 ,5 0年代气旋活动频数较少 ,6 0年代开始到 70年代后期气旋活动频数较多 ,从 70年代末至今又进入一个气旋活动频数较少的时期。贝加尔湖东部地区在 5 0年代初气旋活动频数较多 ,5 0年代中期到 6 0年代中期气旋活动频数较少 ,而 6 0年代后期到 70年代后期气旋活动频数又较多 ,此后气旋活动频数逐渐减少。我国东北地区春季各月气旋活动频数没有明显的年代际变化 ,只有 80年代以来气旋活动频数的振幅较大。东亚沿海春季气旋活动频数较高的地区主要位于我国东北到俄罗斯远东和我国长江中下游到日本一带。从气旋活动路径来看 ,我国长江中下游到日本一带气旋活动路径在各个年代基本相同 ,没有明显的年代际变化 。

Based on the NCEP/NCAR sea level pressure (SLP) data from 1948 to 2000,the frequencies,routes,interannual and decadal variations of extratropical cyclone activities in both inland and coast areas over East Asia in spring have been analyzed.It is found that in spring (March,April,May),there are three areas where the cyclones occur frequently,in which one area locates to the south of Mongolia High(101°E,45°N),one to the east of Baikal Lake(115°E,53°N) and the other in northeastern China(126°E,53°N).During spring,there are obvious decadal variations of cyclone activity frequencies at the Mongolian cyclone activity center,with less cyclones in 1950s,more cyclones from 1960s to 1970s and less again from late 1970s.To the east of Baikal Lake,cyclones occur frequently in the beginning of 1950s,sluggish from middle 1950s to middle 1960s,more cyclones occur from late 1960s to late 1970s,and then less cyclones occur.In northeastern of China,no clear decadal variations have been found,except that the variation amplitude of the cyclone activity frequencies increases after 1980s.In the eastern coastal area of east Asia,cyclones occur frequently over the regions from the northeast China to far east of Russia and from the Yangtze River to Japan in spring.As for the routes of cyclone activity,only in the area from northeast China to far east of Russia a little difference is found in different periods.Further analysis shows that frequencies of cyclones in north China correlate to the frequencies of sandstorms and rainfall in spring to some extent.