Based On 3s Technology In Beijing Wetland Dynamic Monitoring And Evaluation Methods

The wetlands of Beijing perform an important function in developing Beijing regional economy, maintaining regional ecological balance and stabilizing environment function. But now, there are some outstanding problems before us in pretending and managing wetlands: we have no idea of how many wetlands we have, and we know precious little about their dynamic change trend and destroyed situations. Only 3S technologies can help us to dynamic monitor wetlands and their eco-environment timely, accurately and macroscopically, and on the basis of it, we can comprehensively evaluate wetland eco-environment quality.There are two aims of this paper, one is dynamic monitoring Beijing wetlands and their eco-environment by 3S technologies, and the other is establishing a perfect evaluation system of wetland eco-environment quality in order to evaluate wetland eco-environment quality. The involved researches include as follow:Supported by RS and GIS technology, combining the former achievements in scientific research and lots of field investigations, we used Landsat-TM/ETM+ images of 1984, 1989, 1992, 1996, 1998, 2002 and 2004 as information sources to overall investigate and dynamic monitor Beijing wetlands, including wetland type, area, distribution, exploitation, etc. We processed images selected using PCI 9.0, and then translated the format into Geotiff format. We set up interpretable symbols of different wetland types, including reservoir wetland, river wetland, lake wetland, division canal, rice paddy and fishpond, then carried out images vectorizaton, spatial analysis and data statistics using ArcGIS 9.0. On the basis of it, we can analyze the dynamic changes trend and the reasons. It turns out that: of all types, area of reservoir wetland is largest, next are rice paddy, fishpond and river wetland, while division canal and lake wetland are relative small; total area took an upward trend before 1996, and got to the top in 1996 and 1998, reached 677.29 km2 and 505.84 km2, after 1998, the wetland resource degenerated sharply, from 1998 to 2004, the wetland area has dropped 39.8%. The cause mainly lies in reduction of yearly precipitation and upper stream inflow.Establish evaluation index system of Beijing wetland eco-environment quality by combining the AHP method with the PSR model, including climate state, water state, soil state, vegetable state, landscape state and land use state; according to the domestic and overseas standards, make evaluation standards; then evaluate wetland eco-environment quality by using integration index method. Take Yeyahu wetland national nature reserve and Miyun reservoir ecological regions as example to evaluate their eco-environment qualities. It turns out the eco-environment quality of Yeyahu wetland national nature reserve is relative worse, in rank V,...