Remote Sensing Application Study on Environmental Hazards in Shaanxi, China
Yang Minjun
Shaanx Remote Sensing Center Xian. Chian
It is a very important subject for the protection of environment and development of economy in the present world to make reasonable exploration and good use of natural resources, take precautions against natural hazards and try every means to lessen the aftermath of each disaster. Shaanxi Province is situated in the center of China, enjoying natural landsenes of the North and the South, The west and the East Shaaxi is rich in datural resources by suffers serious natural hazards.
Shaanxi Remote Sensing Center has made application of remote sensing technology in the survey and intergraded evaluation study on geology, mineral resources, land use, ecological environment and natural nazards is Shaaanxi Province, providing scientific basis for reasonable exploration and use of natural resources and for the protection of environment for the protection of environment for the province.
The major natural hazrtds hitting Shaanxi are land desertization, land erosion, landslide, debris flow, earthquakes. Active structures, ground figures, surface subsidence, ground water pollution, air pollution and storms, hails, droughts and so on. Most of the hazards are local, though, the damages are quite great.
Remote sensed survey of environmental bazards are various natural or rectificial evolution and events of variations which happen on surface of the earth and bring disasters to human society. These evolutions and events often leave director or indirect marks or records of the events on the surface of the earth. Remote sensing images are true portraitures of the natural landscene of the earth’s surface and they show various marks, prints, or hints of the environmental disasters directly through interpretation of the images. And these are the main basis for remote sensing study on environmental hazards and also the essential information for the study of distribution of environmental hazards.
I. llazards of Land Descrtization
Land desertization hazards mainly occur along the Great all in the Northern part of the province. Some are in the joining area of the Weihe River and the Yellow River in the east of Guanzhong. Land desertification are marked clearly on images and can be circumscribed accurately. And according to the distribution, the areas and the development of the
moving dunes. Stable and semi-stable dunes, and forestry, grass clusters, four kinds of damaging intensities, or say seriousness, of serious, strong, developing and potential can be classification for the land desertization of the hazards hit areas. Evaluation can also be carried out for the achievements in plantation and in battles against desertification. Through studies of comparison of images of different period of time, it is concluded that local land desertification hazards are still going on inside the province.
II. Liazaros Soil Errosion
The loess plateau in the Northern Shaanxi is one of the most serious areas of soil erosion along the Yellow River. The intensity of damage is indicated by the structure features of loess geomorphology and formation of river system. The classification of soil erosion intensities of certain accuracy and various degrees scan be obtained. Through statistics study of loess dones and valleys shown in the large scaled remote sensing images, and by classification of developing types of these valleys, and the evaluation of the features of geomorphology, and then through necessary processes. It is concluded in the study that soil erosion in the north of the Yanhe River is quite serious and in some parts of the belly areas in Southern Shaanxi, soil erosions have become clearly damaging hazards.
