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Poster Session Q
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Dynamic monitoring of desertization environment using Remote Sensing technique in Qinghai
The environmental characteristics of sand area and the developing trend of desetization
The forming of a desert would have a process of generating , developing and evolution and be affected and contrained by natural and cultural environments. By remote sensing studying, the main charcteristics of environment of sandy area are:
- Characteristics of Gological History
Qinghai is located in Qinghai-Xizang plateau and the desert in Qinghai has close relation with geological development. Since Quaternary period, Ximalaya mountain and Qinghai-Xizang plateau have been rising at a large scale from 1000m of Neogene Period to the present 4800 m [4] and now it is still rising.
- The Conditional Characteristics of Sandy sourse
The thick sediments of river lake facies are the main sourse of desert which is proved by sandbody granularity, C14 measurement and contrast analysis of heavy minerals [5] in Gonghe basin, The cyan-cyan white strips, rings and concentric circlar features(21550km2) resulted by wind erosion from cemetation, semi-cemen-tation sandstone, siltstone of Tertiary Period in Chaidamu Basin have close relation with coresponding accumulation of desert in leeward side and which is the main sourse of desert accumulation of desert in leeward side and which is the main sourse of desert accumulation in this basin.
- Characteristics of Climate Elements.
Qinghai desert is chracterized by much dryness, little rainfall, low tempreature and cold, winds almost in WN frequent and strong, and strong evaporating. These characteristics are distinctive in zones. On the satellite images, the kinds of vegetation (forest, bush, grassland), quality (types of grasslands) are in parallel distribution in NE, the coverage is decresing from ES to WN , from mountain area to sandy area of basin, from dark red, red to cyan, cyan white in color. Those gradual changes are the direct indicator of the the climate action, and which produces the same influences to lake area (Fig.7).
- Characteristics of cultural Environment
The social development and growing human activities bring strike influences to environments. The activities of over cultivating , grazing , and wood cutting have distrupted the land resources and led to land desetization, grassland degeneration and environmental deterioration. The desetization still spreads though the natural environment has been improved and the changing velocity of farmland and water area has been slowed down (Fig.8)mean while the reforming of environmental desertization is rather difficult.
mental deterioration the desertization still spreds though the natural environment has been improved and the changing velocity of farmland and water area has been slowed down (Fig.8) Mean while the reforming of environmental desertization is rather difficult.
As mentioned above, the dry climate and strong wind are the power to form and develope the desert in Qinghai. The large area of loose sediments provides enough sanday sources; The natural and potential elements are the basis of generating and developing desert; And the human activities are the leading factor to strengthen desertization; The development and trend of Qinghai desertization are chracterized by spreading, sand dunes invading into the margin of oasis, stabilizing and semi-stabilizing sand dunes acting , the area of wind erosion expanding , water area decreasing , environmental deterration ect.
Ecologic environment in Qinghai is very weak (especially in north side of 35°30'). The rising of Qinghai-Xizang plateau would influence this region furtherly.; dry climate is going on furtherly; The environmental disruption caused by human activities is getting worse and desertization will be intensified.
Fig 8 Dynamic changes and different types of Qinghai Lake
Conclusion
The protection of environment and ecologic balance are the first important task tp harness the desetization. Bassed on the environmental chracteristics of desertization and its origin, surface morphology, scale and the relation with surrounding setting, we should enchance the regional management and certain the reasonable usage of resources, land use and protection by control-ling population and protecting the present forest and grassland resources, developing and utiilizing the water resources properly, reforming the energy structure in the countryside of desert area.
From practice, remote sensing technique is an effective tool to investigate, study and dynamically monitor environmental deserization. It plays an important role in forecasting the nature developing trend and harnessing of desert.
References
- Zhu Zhenda etc. An Introduction to Desert in China, Science Press, 1980.
- The research group of applications of the National Land resources satellite data in the region of Beijing, Tianjin and Tangshan: The Application of the National land resources satelite data, science Press , 1988.
- Zhong Decai , Lu Jinhua: Desert Map of the people's Republic of China (1:4000,000), Map Press, 1979.
- Geng Kuanhong : The Climate of Desert Region in China, science Press, 1986
- Xu Shuying : Accumulation of wind sand in Gonghe Basin in Qinghai, Desert in China, Val. No.3 1982.
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