Remote sensing analyses of spatio-temporal changes of the ecological environment in the lower reaches of the Tarim River.

The ecological environment in the Tarim River Basin is extremely fragile. The ecological problems resulting from local economic development in this region have been a hot topic for the ecological scientists. There is a new trend to use information technologies to monitor the ecological environment dynamically by means of the modem information technologies. To meet the constant requirements of long-term monitoring of a region ecological environment, this paper focuses on the vegetation coverage and land desertification on the basis of the information technologies of remote sensing (RS), geographic positioning systems (GPS), geographic information systems (GIS), and data warehouse, applying the theory of the integrative spatial and attribute data, seamless integration of multi-source data. The ecological environment for the lower reaches of the Tarim River is analysed qualitatively and quantitatively. The investigated database is established and managed through multisource and multi-type massive data, which are collected from three periods of the remote sensing images and background data in 1999, 2002 and 2004, respectively. The methods of system classification, remote sensing interpretation, vegetation coverage, conversion models construction, and massive data built database are applied to analyse the data concerned during the dynamically monitoring the ecological environment in the Tarim River Basin. The results show that the vegetation coverage has increased gradually each year after the emergent water transportation project was started, whereas the desertification area has decreased, some sand areas have obviously retreated. The speed of improvement in the east part of the river has been higher than in the west. The ecological environment in the lower reaches of the Tarim River has tended to improve after the emergent water transportation project in the lower reaches of the Tarim River Basin. In conclusion, the emergent water delivery plays a decisive and significant role in promoting the ecological environment in this region. [ABSTRACT FROM AUTHOR]