Using remote sensing data of TM and ETM+ in 1992 and 2002, land degradation based on land use changes, especially sand changes were analyzed and land degradation status in 2002 was evaluated in the Huan Beijing Area. The area of sand in 2002 is 6669.6 km<sup>2</sup>, increased 716.2 km<sup>2</sup> compared to that in 1991, and most of the newly-produced sand came from grassland. Land degradation status in 2002 was evaluated by the combination of vegetation, soil and topography information and the region was divided by 1km ×1km cell as the evaluation unit by the application of the GIS. The indicators of land degradation evaluation included soil organic, soil depth, vegetation cover (NDVI) and slope. Land degradation index (DI) was computed, considering the contribution of different indicators to land degradation. The land degradation status was divided into four types according to DI, no-degradation (DI > = 55), slight degradation (50 = < DI < 55), moderate degradation (40 = < DI < 50) and severe degradation (DI < 40). The results showed that the area of degraded land is 132900 km<sup>2</sup>, which occupied the percent 58.2 of the whole Huan Beijing Area and the proportion of slightly-degraded land to degraded land is about 0.47. The political county taken as an evaluation unit, the partition of land degradation in this area was also analyzed based on land degradation area proportion and degree. Six types of land degradation partition were got.
Land degradation processes, which imply a reduction of the potential productivity of the land (e.g., soil degradation and accelerated erosion, reduction of the quantity and diversity of natural vegetation), result from a long history of human pressure upon land resources as well as from interactions between varying climatic characteristics and ecologically unbalanced human intervention. The north-west region outside of Beijing, is one of the most important regions where many departments invest most and pay most attention. The land degradation and other environmental problems in this region affect not only Beijing but also the surrounding area. This paper analyzed characteristics of land degradation actuality situation in the NW region of Beijing, based on TM (ETM) in 2002. The wind-eroded land was mainly distributed in north of Yin Shan Mountain. Due to degradation of grassland, the sandy land increased from 1991-2002, mostly distributed in the monitoring zone of Hunshandake sandy land. The water-eroded land was mainly distributed in monitoring zone of the south of Yin Shan Mountain and south of monitoring zone of Horqin sandy land. The salination-land was mainly distributed in lake surrounded area and the drainage basin of Sanggan River. And To better understand the drive forces of land degradation processes in study area, a multivariate spatial model associated with land degradation is found by the explanatory variables of Logistic multivariate regression model(LMR). The explanatory variables include wind speed, soil humidity, soil organic matter, NDVI, average precipitation, soil slope, et al. The value of the parameter estimated by model with their corresponding standard error, chi-square statistics, and significance probability are analyzed to find the driver of land degradation in studied area. And the high or low probability of land degradation is predicted. Finally, suggestions to the eco-environment construction of the studied region have been put forward.
The aim of this work is to apply hyperspectral remote sensing technique to land quality monitoring to explore its application potential in this field. According to the characteristics of hyperspectral remote sensing technique combining with spectral features of land quality indicators, we use multivariate statistics methods and approaches based on spectral position variables, explore the spectral indicators sensitive to land quality, set up the retrieval models of land quality indicator, study the potential of applying hyperspectral remote sensing technique in land quality monitoring. Attempt to ameliorate land quality monitoring techniques, expand monitoring extents, decrease the self cost of survey, shorten the survey period, and make the results more scientific, objective and stable by this technique.
A land use/cover classification system is important for land resource management and it is one of the key research issues in Land Use /Cover Change (LUCC) and land change science research. Lots of work has been done in this area, however, a universally-accepted classification system has not been available yet. This paper proposed several guidelines for building a land use/ cover classification system, which encompasses the basic concept of land use and land cover. Then a preliminary framework for Chinese land use/cover classification system at different scale based on remote sensing data was detailed. The framework is made up of four scales, including national scale, regional scale, county scale and country scale. The classes of first level at national scale in the system are agriculture land, woodland, natural grassland, built-up land, water, wetland and barren land. The regional scale includes 27 classes of land use/cover and the county scale includes 43 types. The general diagnostic criterion of the first level of classification system is the situation of existing vegetation, soil and water, artificial and natural surface. Monitoring on land resource in Beijing-around area as an example, this paper introduce the respects need to be paid attention of this classification system. Because of the complexity and difficulty of this question itself, this system was based on synthesis of relevant research achievement; its actual feasibility still remains to be verified.