Global, China-Mongolia Arid- and Semiarid\|Areas (CMASA) andthe Details of Precipitation Distribution in Part Regions of CMASA
2011, 30 (1):
In this paper, after the simply review and intercomparison of the global eight major arid-and semiarid-areas have been done, also and the CMASA size, area, name and the some details of the precipitation distribution over part regions of CMASA have been calculated and analysed. The some main conclusions are as follows: There are eight major semi-permanent arid- and semiarid-areas totally in the world. They are the North Africa-, MidwestAustralia-, Central Asia-, China-Mongolia and Midwest America arid- and semiarid\|areas and so on, are mainly located in Africa, Asia and Oceanica. The CMASA is linked together and should be treated as a whole, not in partly. If taking simply the multi-year mean rainfall less than 200 mm and 200~500 mm as the criterions of arid- and semiarid-areas, respectively, then the CMASA covers both the entire Mongolia and north China bording on Daxinganli-Luliangshan a line to the east and the latitude of 36°N to the south, has the totally area of 5×106 km2, with the main body, making up 69% of its total area, and the extremely arid on China side. And it is the homeland of nearly one hundred million populations in China-Mongolia. The CMASA is dry in the middle, something wet on its south- and north-sides. On the China side, the southmost part of Shaanxi is quite humid, with the mean rainfall as much as more than 900 mm, but in the inland hyper arid region, Toksun, the east end of South Xinjiang Basin, is with the rainfall less than 7 mm only; on the Mongolia side, its central and northern part is with the rainfall more than 400 mm; south part, nearly 100 mm; its southwest corner, just 30 mm. The CMASA is a unique mid-latitude, inland dry zone in the Earth. There are four dry centers in isolation in the extremely dry region of the east end of South Xinjiang basin. That is the common impact of the thermal dynamical inducing compensate descent of Qinghai-Xizang Plateau (QXP) topography on the large scale and Fohn effect on leeward side of East Tianshan and Arjinshan orography on the meso-scale. And also there is a obviousextending southward ‘V’ shappeddry valleyon the northeast side of the QXP, that is the impact of thermal compensatedescent of QXP orography as well.