Summary The Effects Of Environmental Factors On Dynamics Of Veget. Ation Cover Based On Ndvi In Yanchi Country

Yanchi County at the eastern part of the Ningxia Hui Autonomous Region, betweenlatitude37°04'~38°10', longitude106°30'~107°47' between the northern part of theMu Us desert connected to the south and the Loess Plateau, rely on, is located in aridandsemi-arid transition zone on the geographical location of the transition zone from the LoessPlateau to the Ordos tableland Yanchi County in vegetation from steppe to desert transitionzone in the transition zone from rural areas to the pastoral areas of resource utilization,in atypical pastoral area, is the only animal husbandry county in Ningxia. Grassland degradationin the area under the combined action of natural and man-made, a serious threat to localeconomic development and ecological security. Yanchi County, since the end of2002,implementation of the grazing prohibition, in order to better the area of the development ofthe grassland vegetation status in real-time dynamic monitoring to understand the trends ofgrassland vegetation, according to the national standard (GB19377-2003) and remote sensingdata from Yanchi County grassland vegetation coverage, select the grassland vegetation coveras the evaluation index, vegetation index (NDVI) and the dichotomy pixel (sub-pixeldecomposition), the establishment of Yanchi County grassland vegetation cover remotesensing monitoring system, the region grassland cover conditions changes in remote sensingmonitoring and evaluation, the following results:(1) Yanchi County proceed according to the grassland vegetation cover the actualsituation, based on remote sensing data and the national standard (GB19377-2003), based onYanchi County grassland vegetation coverage for the evaluation of indicators, combined withremote sensing vegetation index (NDVI) and sub-pixel decomposition method (like thedichotomy), Yanchi County grassland vegetation coverage of remote sensing estimationcalculation and validation based on field survey data, Yanchi County grassland coverage for11consecutive years, the situation changes remote sensingmonitoring and evaluation,indicating that this model of remote sensing estimation of vegetation coverage is effectivepractical.(2)2000to2010,11years Yanchi County grassland vegetation cover significantlyimproved, very low vegetation cover grassland reduced1462.39km~2; in coverage grassland,high coverage grassland, high coverage grassland increased by586.39km~2, indicating that although as a whole tends to improved. But the situation is not very optimistic, low and verylow coverage grassland up level transfer of the county desertification be reversed during thisperiod, but low coverage grassland part to retain the larger, indicating that in this periodgrassland as a whole to the positive direction, but slow. The common role of the human andnatural factors, continue to enhance the grassland ecological construction investment,grassland overall situation will be a qualitative change. The application of this methodachieved a high accuracy vegetation coverage in Yanchi County.(3) under the natural and human factors, the size and grade of the different grasslandvegetation cover in the evolving use of Markov chain in the county,2000,2005and2009remote sensing data of the auxiliary objective the reactions of the county's overall grasslandcover condition, so the horse Cove chains can be effectively applied to the dynamic changesin evaluation of grassland cover, the results are reliable.(4) the GIMMS, and MOD13Q1data set, covering the grassland vegetation of YanchiCounty Temporal and spatial analysis studies have shown that: the GIMMS, and MOD13Q1data sets can be used to a certain scale of grassland vegetation cover change, and to goodeffect, this data set bold explorations in the grassland resource monitoring applications andinformation mining.