| Climatological characteristics, which can provide some drought or flood years with large-scale background, are investigated for large-scale water vapor transport over Asian-Australian Monsoon Region based on vertically integrated water vapor flux by pentad from 1980 to 1997.At the same time, the differences of moisture transport over the Yangtze River Basin between drought and flood and the moisture budgets over eastern China from April to September are examined. Major results are as follows:I . In winter (January), there are four nearly latitudinal moisture transport belts (channel) over Asian-Australian Monsoon region. They are closely related with the easterlies and westerlies over Southern Hemisphere and Northern Hemisphere. In boreal winter, Asian monsoon region is moisture source; the cross equatorial moisture transport channels transport the moisture to Australian monsoon and south Indian Ocean from Asian monsoon region. In summer (July), the obviously feature is that there exists the strongest moisture transport formed by the currents from different sources, It originates from Southern Hemisphere, passes Arabian Sea, the Bay of Bengle, the indo-China peninsula, the east China, Korea and Japan, at last flows into the north Pacific, like a big river. Asian monsoon region is moisture sink, the cross equatorial moisture transport channels transport the moisture from Australian monsoon and south Indian Ocean to Asian monsoon region, which is moisture sink. The change of transport pattern from winter to summer closely relates with the change of the direction of the cross equatorial moisture transports, especially nearl 05 E and 45 E.II. The northward march of the southerly moisture transport with the summer monsoon transport over the East Asian (110-130 E) shows the feature of staged jumps. Each jump relateswith the large-scale important weather incident in China. The southerly water vapor can progress to 50 N near North-East in China-, the southeasterly water vapor from south side of the west pacific subtropical high and north side of the monsoon trough can march westward to 100 E near south-east part of GanSu in summer. The strong convergence areas, which are coincide to the big rain belt, mostly lie in the planetary-scale water vapor transport.III. The most obvious feature of the first leading term of EOF applied to the climatic vertically integrated water vapor flux over Asian-Australian Monsoon Region shows a planetary-scale southwesterly moisture transport, starting from south hemisphere, passing over Asian monsoon region and flowing into North Pacific, which indicates the interaction between the northern and southern hemisphere as well as between mid and low latitudes in the Northern hemisphere. The 1st time coefficient shows the staged feature of the progression of the moisture transport over Asian-Australian Monsoon Region, which relates with the large-scale important weather incidents in Asian-Australian Monsoon Region.IV. In drought or flood years over the Yangtze River Basin, the features of the establishment, progression and decrease of moisture transport is significantly different, meanwhile the differences of the moisture transport by the monsoon circulation between mid and low latitudes in the Northern hemisphere, and by the subtropical high are obvious, so are their convergence, especially over South China Sea, the tropical west pacific, the Yangtze River Basin, North China and North-East in China. In the droughts or floods over the Yangtze River Basin, between June and the second dekad in July, the moisture transport from the southern boundary, originating from South China Sea and South China, is the most important influence factor, but between the last dekad in July and August, the one flowing out from northern boundary is the most important influence factor. In drought (flood) years over the Yangtze River Basin, the southerly moisture transport with the summer monsoon can shift to northern (southern) than the normal, the southeasterly water vapor from south...
|
PDF Full Text Request