| Nowadays, water loss and soil erosion has ranked among the leading of global environmental problems, and causes severe natural calamities in many countries. Scholars in many countries have researched the mechanism and process of water loss and soil erosion, and put forward the importance of forests and vegetation in the control of water loss and soil erosion. There are the only coniferous forest of the cool temperate zone in Great Khingan, and Heilongjiang and the Songhua river water system and its tributaries Flow across the Great Khingan. Great Khingan is the important water conservation area. Great Khingan plays a stable role in ecological balance in the northeast region, and has a significant function for the northeast Asian region and ecological construction of our country. Meanwhile, this region plays an irreplaceable role in natural shield protective effect on global climate, because Great Khingan is the production base of the Commodity grain and animal husbandry. In the beginning the forests grow intensively in Great Khingan, with the continuous felling and growth of population, the amount of Sparse Woodlot and Low-yield forest grow rapidly, in addition, the situation such as fire, mining, reclamation, road construction happened frequently, and it caused ecological environment and soil erosion in the Precipitation concentrated area became worse and worse. Under the situation that the soil erosion become worse and worse in Great Khingan, this article integrates the historical data of rainfall, multi-source RS data, geographical information data and the data of survey field, adopts cross of multi-disciplinarity and integration of multi-technology, studies the extraction method of RUSLE’s factor based on amended RUSLE, research interpolation method of Rainfall data space in comparative method using ArcGIS, on the basis of grid method simulate soil erosion amount of forest ecological system in Great Khingan between2000and2010. analyzes dynamic variation of space distribution, make analysis of the space and time changes on soil erosion with DEM, terrain niche index and The center of gravity shift theory, and develop evaluation system of soil erosion with programming language in Great Khingan. The research results can provide reliable basis and scientific guidance for the prevention of soil erosion in Great Khingan. and offer the Theoretical support to the water and soil conservation, restoration and sustainable management of forest resource. The main conclusions and results are following below:1. TM data collection and processing are discussed, including geometric correction, radiometric Calibration, atmospheric correction, solar elevation angle correction, normalization processing of multi-temporal radiation and image mosaics processes. It is necessary to normalize remotely-sensed data in radiation using the time multi-phase when we study on large scale problems. 2. This dissertation discusses the collection and processing of climate data, processes the amounts of daily rainfall data with program of VBA, and according to the way which establish the regression model to increase the dot density, cover the study areas in Great Khingan with rainfall data.3. Use the rainfall data in the Great Khingan and its surrounding18weather stations, based on IDW, SPLINE.OK, OCK and other four kinds of spatial interpolation method, spatial interpolation simulation and cross examination in the study rainfall annual scale and month scale. Cross validation results show, in all interpolation methods, ranking is OCK<OK<SPLINE<IDW, spatial interpolation effect of OCK method is better than other methods. From four methods for monthly rainfall data interpolation results in2007,6-9months of the interpolation result uncertainty is less than11-3. Based on the ordinary co Kriging method in4Great Khingan areas and14neighboring sites of multi-year average precipitation interpolation, get the distribution characteristics of average rainfall space research area for many years, the annual rainfall in Great Khingan in between358-462mm, the center of heavy rainfall in the southern part of Huma County, the maximum value is462mm, the low value area in Western Mohe County,annual rainfull precipitation is358mm.4. Using ArcGIS to extract the raster map NDVI vegetation index and related slope, grid map, elevation to geographic information in order to establish the quantitative remote sensing model inversion of vegetation coverage.5. By calculating the mode of systematic review of soil erosion factors, and according to the geographical features and data obtainment conditions of Great Khingan, selection of calculation method suitable quantitative factors of erosion of soil in Great Khingan, and make appropriate adjustments to the related method. This research finally according to the methods in the existing research data combined with soil types of the study area to determine the soil erodibility factor K value, using the monthly rainfall estimation of R value to determine the rainfall erosivity factor R value of vegetation coverage, the inversion model of RS and GIS is determined based on the cover and management factor C value, calculation LS non cumulative flow is determined based on the slope length factor LS value, determining the factor of soil and water conservation measures P value using the Wener empirical formula method. Compared with the previous research results obtain the calculation model of the factors is reliable. applicable to all factors in Great Khingan to obtain.6. Based on the RUSLE model, the quantitative evaluation of the Great Khingan in2000and2010two of the soil erosion, and through the terrain niche index and spatial center of gravity transfer model theory, the evolution of soil erosion in Great Khingan in11years time to reveal. The results showed that:during the period of2000-2010, the amount of soil erosion in Great Khingan, the overall upward trend, mainly to reduce3929.37km2in the micro degree of soil erosion area, mild erosion area increased by3911.65km2, several other erosion type has no obvious change. On the whole, micro degree erosion area decreased and mild degree erosion area increased as the same number, the total increase in regional soil erosion. Constraint topography erosion intensity on the temporal and spatial distribution of soil in Great Khingan is very obvious, the intensity of soil erosion types in the topographic gradient distribution pattern was significantly changed. During the2000-201011years, micro degree erosion shrinkage tendency in the terrain, and mild erosion is the expansion of the trend in the terrain, other types of erosion in the topographic position did not change significantly, that in these11years, types of transformation from micro degree erosion to mild erosion the superiority of Great Khingan. From2000to2010, in addition to micro degree erosion expansion to the southeast area, center of gravity of several other types of soil erosion intensity to the northwest shift, but the specific angular offset and offset distance is not the same. The micro degree erosion offset the shortest distance is1.98km, and the moderate soil erosion offset the longest distance is29.22km, the light soil erosion followed by25.11km. Great Khingan, above moderate soil erosion are concentrated in the southeast, the regional soil erosion is facing tremendous pressure, should strengthen the management, formulate corresponding measures for soil and water conservation.7. Study on the evaluation system of soil erosionEvaluation system of soil erosion in Great Khingan. several major modules of the system to be ncluded factor calculation, calculate the amount of soil erosion, database, map function, realize the quantitative evaluation of soil erosion in the study area. |
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