CLIMATE CHANGE AND RIVER SEDIMENTATION IN MONGOLIA

摘要

As you know, Mongolia is land locked country in Northeast Asia, locates between the latitudes of 41° 35'N and 52° 09'N and the longitudes of 87° 44'E and 119° 56'E and is sandwiched by Russian Federation and People's Republic of Chine (Fig. 1). Covering area is 1.564 thousand square km's and it's territory is lifted relatively high altitude above the see level, 81.2 percent of the territory situated at the level higher than 1,000 m, 50 percent -higher than 1,500 m, the average altitude is 1,580 m above the sea level. Mongolia has unique ecological system consisting of the southernmost fringe of boreal forest of the Great Siberia, the northernmost deserts, vast steppes of the Central Asia and chains of Altai, Kangai, Khentei and Khyangan mountain massifs. All natural zones such as high mountains, valleys between the mountain ranges, wide steppes, Gobi-desert and semi desert zones are combined. The territory is surrounded by high mountains that filter both from the northern and western cold airmass and from Pacific moisture airmass. Ecologically, Mongolia occupies a critical transition zone in Central Asia: here the great Siberian taiga forest, the Central Asian steppe, the high mountains and Gobi desert converge. The climate of Mongolia is harsh continental with sharply defined seasons, high annual and diurnal temperature fluctuations, and low rainfall. Because of high altitude and latitude, it is generally colder than of other countries of the same latitude.