摘要
文中利用1948—2002年NCEP/NCAR全球再分析资料,1958—2002年ECWMF再分析资料,中国国家气候中心的618个测站1961─2005年的逐日降水量资料,采用作者确定的东亚夏季风(EASM)建立标准,探讨东亚夏季风在南海爆发以后继续向北和向东推进活动范围、建立、持续和撤退的时空分布特征,结果表明:(1)给出东亚—西北太平洋地区的东亚夏季副热带季风(EASSM)的定义,计算其建立时间(候)和空间分布,发现EASSM除继续向北推进的方向外,在20°─25°N还有明显向东的分支,以及向西稍偏北的分支,107.5°E以西的季风建立等时线梯度十分密集,而以东的等时线梯度很小,季风建立的等时线的总体以110°─115°E为轴心、明显向中国华北和东北地区凸起的近于折线的分布,表明EASSM先在中国大陆建立,而同纬度的中国近海和西北太平洋地区的夏季副热带季风后建立;(2)撤退的等时线则近于与建立的等时线相反分布,沿120°E的方向凸向南,表明中国东北地区和近海地区先撤退;(3)给出东亚─西北太平洋地区EASSM建立的概率等值线的空间分布,我们尝试定义了<35%概率等值线的地区为其影响的边缘地带,北边界始于黑龙江省北部48°N附近向东南经由黑龙江省南部和俄罗斯滨海省,穿过日本海止于日本北海道南部,其西边界由东北向西南沿中蒙边境止于青藏高原。20世纪90年代北部边缘地带与多年平均比偏南3─5纬度,而西部边缘变动较小,只向东偏了1个经度。
The NCEP/NCAR global reanalysis data from 1948 to 2002, the ECMWF reanalysis data from 1958 to 2002, the National Climate Center （NCC） daily precipitation data at 618 stations in China, and the onset criterion of the East Asian subtropical summer monsoon （EASSM） defined by author, are used to investigate the northward and eastward marching domain of EASSM after its onset in the South China Sea, as well as the spatial-temporal distributive features of the onset, persistence, withdrawal of the EASSM. The results show that （1） except the northward marching main body of EASSM, there are also an eastward marching embranchment and a northwestward marching embranchment between 20° - 25°N; and the isochrones of onset date are very dense west of and sparse east of 107.5°E, displaying a north-convex polygonal line pattern along 110° - 115°E toward North China and Northeast China, which indicates the onset of the EASSM first over China mainland, and then successively over China offshore waters and the Northwest Pacific region at same latitudes. （2） The isochrones of withdrawal date are, on the contrary, a southward-convex polygonal line pattern with its convex points approximately along 120°E, suggesting the withdrawal of the EASSM first in Northeast China and China offshore waters. （3） The area with an influence probability of less than 35 % is called the marginal influence region of the East Asia-Northwest Pacific EASSM. The north marginal region starts from 48°N in the north of Heilongjiang Province, goes southeastwards through Primorsky Kari in Russia and the Sea of Japan to Southern Hokkaido, and the west marginal region goes along the China-Mongolia border southwestwards to the Tibet Plateau. In the 1990s, the north marginal region was 3 - 5 latitudes south of the normal position, but the west marginal region only one longitude east of the normal.
出处
《气象学报》
CAS
CSCD
北大核心
2007年第4期503-510,共8页
Acta Meteorologica Sinica
基金
国家自然科学基金(40275019
40575047)
中国气象局科研重点项目"现代气候变化对吉林省西部荒漠化影响的监测和评估研究"
吉林省重点课题(20020417
990218)
关键词
东亚-西北太平洋地区
夏季副热带季风
建立和撤退
活动范围
East Asia-Northwest Pacific region, Summer subtropical monsoon, Onset and withdrawal, Active domain.
