Remote sensing detection and spatio-temporal change analysis of wetlands in Xinjiang arid region

Abstract: As a part of globle ecosystem, the wetland plays an important role in arid region eco_environment system. The area change of wetland will greatly influence the regional environment. In order to understand the wetlands distribution status, change processes and temporal pattern characteristics in China arid zones under the environment of global change, this paper used multi-source remote sensing data (TM, ETM+ and CBERS_02) to achieve the arid zone wetlands multi-stage monitoring through object-oriented classification technology and semiautomatic method. Firstly, we used object-oriented technology and hieriarchical classification algorithm, achieved preliminary wetlands infomaiton extraction, and checking the classification accuracy of the primary result by manual visual interpretation. Then, we completed 3 times wetlands distribution mapping on year 2000, 2005 and 2010. On that basis, we analyzed the characteristics of wetland spatial distribution and temporal variation in the past 10 years via land use dynamic change model and the geo-statistical method. The research results show that, 1) Wetlands in Xinjiang arid area has increased by about 10% in the last 10 years on the whole. The total area of wetlands reached to 22 438 km2 in 2010 in Xinjiang arid region of China, which increased approximately 2 065 km2 compared with the area in 2000. 2) In the spatial distribution, wetlands in the southern and northern Xinjiang are uneven. Wetlands in the southern Xinjiang accounted for about 76% in total wetlands area, and wetlands in the northern Xiangjiang only accounted for 24%. Wetlands Xinjiang arid area mainly distributed in the south of Xinjiang Tarim river basin. And in different basins, wetlands spatial distribution have different characteristics. 3) On wetland types composition, in year 2010, the ratio of river wetland, lake wetland, marsh wetland and artificial wetland are 42.73%, 29.43%, 17.98%, 8.92% and 0.94% respectively. 4) In change process, all type wetlands showed a growing trend in the past 10 years, but the increasing amount and magnitude are different. The variation on different type wetland presents different characteristics and inter-class differences are large. Among them, the dynamic change of marsh wetland and constructed wetland are 2.58 % and 2.43%; The dynamic change of rivers wetlands and lake wetlands are 0.59% and 0.43%. The largest net increased values are marsh wetland and river wetland, which increased by 827.92 km2 and 531.86 km2 respectively, account for 65.85% of the total increase amount. With the Global warming, rising temperature and increasing precipetation in resent years in Xinjiang district is the main driving force of wetlands increase. And, the human activity intensified the complexity of wetland spatio-temporal change process.