| As one of the ten major environmental problems that threaten the survival anddevelopment of human beings, land desertification can have regional-scale andglobal-scale environmental effects; it is among the important issues of the research onglobal environmental changes. The environmental deterioration as well as theeconomic poverty that caused by this problem have become the important factors thatrestrict the global economic development and affect social stability. Desertificationmay not only cause the destruction of the local ecological environment but also havean impact on the regions thousands of miles away.Mongolia is the second biggest inland country and nearly90%of its land islocated in the arid and semiarid climatic zone; in addition, it is also one of the nationsthat suffer the severest desertification in Asia. The farming-pastoral eco-tone innorthern China----the region that has the land desertification at the highest level withthe most extensive land distribution, borders upon the region of Gobi desert.Consequently, the occurrence, development and treatment of the desertification therehave a close connection with those in Gobi desert in Mongolia. The protectivemeasures such as building the Sanbei shelter-forest project and returning land forfarming to forestry or grassland appear to be effective. Moreover, the sand-dustweather in the north is decreasing year by year and the area of land suffering from thedesertification also diminishes. None of these can be achieved without the endeavor ofChinese people. Although the desertification of our country is looking up gradually,the present situation of Mongolia adjacent to us as well as whether it may bring someinfluences on our country are the issues worth taking into consideration. Thus, thispaper studies and discusses the influence of the sandy desertification in Mongolia onthe one in the Northeast China.This paper, based on the RS and GIS technology, takes the TM, ETM togetherwith CBERS data as the data source of the images. It extracts the information of thedesertification of Mongolia via the man-machine interactive interpretation so that the author can obtain the distribution of the sandy desertification in Mongolia accordingto the data got from the interpretation. In the meantime, by using the methodsgrounded on GIS, this paper conducts the analysis of the spatial-temporal dynamicchange, transfer matrix, dynamic degree as well as the intensity of change of thesandy desertification in Mongolia. After getting the data from the interpretation ofthree periods focused on the desertification of the farming-pastoral eco-tone innorthern China, the author can get the situation of the changes of the data. Connect itwith the distribution rule of the local sand-dust weather, the climate, the terrain andother factors the importance of the influence of the desertification outside Chineseborders on the one of our nation can be explored.The major findings are as follows:1. The sandy desertification in Mongolia is mainly distributed in the Gobi desertand the low-lying areas in the bedrock mountain area except the mountain district inthe north of the country. It is distributed in the shape of an acre from west to east, withmost part being severe desertification. The total area of the desertification reducedfrom76080.13km~2(1990) to75951.68km~2(2000), while increased to79587.45km~2(2007). On the whole, it is getting worse and worse.2. According to the calculation of the dynamic degree of type of the sandydesertification in Mongolia, the mild, moderate and severest types of sandydesertification are all deteriorating dramatically. The severest type only occupies4.78of the total area but is increasing most rapidly. With the proportion being nearly42.05%, the severe type increased on the whole, it has the tendency of increasingslower and slower. The area of argillaceous desert in Mongolia is increasing rapidlyand rings the alarm for the local people.3. Through the transition matrix, we can see that most of the area ofdesertification is stable especially for the severe type, with the mild type, moderatetype and potential type being obvious. Although the area of desertification diminishedduring the period from1990to2000on the whole, when observing the transitionmatrix, we can find that the phenomenon developed to be worse in terms of thetransformation among the types. Though the area enlarged from2000to2007, itbecame mild in terms of degree.4. When observing the intensity of changes, they mainly occur in the region ofthe Gobi desert that is located in the south and the southeast of Mongolia. The regionof the intensity of change is in accord with the active region of the sand storm.5. Learning from the changes of the focus migration, the center of gravity of the types of desertification is mainly distributed in the area of the region of Gobi desertsouth of Mongolia, with the center of gravity of the severe type being exceptional.Generally speaking, the center of gravity of the sandy desertification in Mongoliareceded to the inland areas which show the deterioration of the desertification.6. The sandy desertification of the farming-pastoral eco-zone in northern Chinamainly locates in the edge of four desert regions as well as6sandy regions. The areaof desertification ranges from245.882.96km~2in1975to270419.82km~2in2000. Aftersome control methods being taken, the area is nearly240853.25km~2. The phenomenonof desertification is looking up gradually.7. Spring is the season where dust weather strikes frequently in north China. Themajority of the sand and dust storms are controlled by Mongolia cyclone and carriesthe sand in Mongolia to our nation in two routes. One starts from the northwest ofMongolia which affects most regions of the north of China while another starts fromthe Gobi desert in the west and south of Mongolia and influence the north as well asthe northwest of China.8. The distribution of desertification of Mongolia is mainly controlled andinfluenced by terrain, showing a tendency of developing from the northwest tosoutheast. At the same time, it is in accordance with the route of the sand storm. Thesouthern regions together with thecentral ones are the main sources of the sand of foreign countries and transmit sand toour nation via strong winds. Changes of desertification in the studied area and thechanges of the sand-dust weather have negative impact on the annual rainfall in theregion, while the temperature has little to do with them. The main factor that thereduction of the sandy desertification in the north of China attributes to may be thehuman governance. We can conclude that the desertification in Mongolia hasinfluence on the desertification of the Northeast China, while such influence is weakerthan the influence of governance. It still needs us to intensify the improvement of theenvironment outside Chinese borders so that the climate of the regions of our nationcan be improved. |
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