The Study Of Desertificated Land Risk Evaluation Around Qinghai Lake Area

This paper selects the largest inland lake in China - Qinghai Lake area as the experimental area, using remote sensing to obtain the test area in 2006.The paper is based on Landsat TM image data of the these periods with the Qinghai Lakebasin vegetation maps, land use map, 1:50000 topographic map, DEM map, meteorological data of Lake District, and socio-economic data as the supplementary information. It also takes software tools ARCGIS9.2, ERDAS IMAGINE9.1 as image processing tools. With the help of previous research results and research needs of this paper, index system is established on selected indicators of desertification risk assessment. Using AHP decision analysis method to weigh each index valueand evaluation model of desertification risk, a comprehensive map of risk of desertification of study area is produced. Analysis of the map shows that:(1) There are four levels of the risk of desertification in the study area: potential risk of desertification, mild desertification risk, moderate desertification risk, and severe desertification risk. In which all levels of distribution of land desertification interlace, and appear continuously banded or patchy, and also serious land desertification is in relatively concentrated areas of human economic activity;(2) Causes for desertification risk are:1, from the natural factors of the study area, the grade distribution of the entire study areat does not follow certain law, which means that climate factors on the development of desertification are influential but is not a decisive role;2, from the inner dangerous factors of study area, the potential and the mild distribution of desertification is at the north of the lake, showed a banded structure. On the contrary, the lake is mainly surrounded by distribution of moderate and severe desertification.3, from the land factors of study area, the entire area has a positive trend of land distribution;4, from the socio-economic factors of study area, moderate and severe desertification desertification mainly is distributed in the populated areas;Overally speaking, the natural factors in study area are predisposing factors for desertification, whose main driving force is climate. Human factors play a leading role and the increase in population caused by human activities is the most fundamental reason. Land desertification is a result of the interaction of natural factors and human factors.