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Yuan P.,Wuhan University | Qin C.,Wuhan University | Qin C.,Hubei Institute of Land Surveying and Mapping
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University

The most important causes of horizontal reference stations are human factors such as excessive pumping of groundwater and immoderate mineral exploitation. GPS data from Anhui Operating Reference Stations (AHCORS) between 2011-11 and 2013-9 was continuously processed the using GAMIT/GLOBK software. Then, based on these results, the 3D velocities of the reference stations were determined, and crustal horizontal movement and land vertical movement was analyzed in detail. It was found that the mean horizontal velocity of AHCORS reference stations was 34.44 mm/a in the direction of E18.01°S under ITRF2008 reference frame and 6.13 mm/a in the direction of E7.31°S with regard to the Eurasia Plate. Stations located in Huaibei Plain have moved in horizontal with 1~4 mm/a relative to No-Net-Rotation of the whole AHCORS. Tancheng-Lujiang Fault showed sinistral strike slip feature between Jiashan and Sixian, with very weak movement in the south of Jiashan. As for the vertical direction, AHCORS reference stations uplift in the south of the Huai River, but subside in the north of it. The average uplift rate of the stations located in the south of the Huai River is 2.72 mm/a, while the average subside rate of the stations located in the north of the Huai River is 2.98 mm/a. © 2016, Wuhan University All right reserved. Source

Li L.,Wuhan University | Xia H.,Wuhan University | Li Z.,Hubei Institute of Land Surveying and Mapping | Zhang Z.,Tianjin Institute of Surveying and Mapping
Remote Sensing

Four natural lakes in the middle and lower reaches of the Yangtze River-Dongting Lake, Poyang Lake, Chaohu Lake and Taihu Lake-play a key role in the climate, environment, and ecology of this area. Upstream of these lakes, the Three Gorges Dam Project has been storing water for 12 years. Future monitoring and management of rivers and lakes can certainly benefit from research on the patterns of variation of natural lakes downstream of the Three Gorges Project. This research applies Landsat TM/ETM data to evaluate water area changes in the four lakes from 2002 to 2013. The water area is estimated using AWEI (Automated Water Extraction Index) from satellite images. The average areas decreased respectively 452, 11, and 5 km2 (29.6%, 1.4% and 0.2%) from 2002 to 2013 for Dongting, Chaohu, and Taihu Lakes. Meanwhile, it increased 300 km2 (11.0%) for Poyang Lake. Precipitation and changes in river inflow may account for the fluctuation in the surface area to a large degree, especially between 2009 and 2013. The present study was undertaken to characterize the evolution of lakes and to explore the potential driving force of variation in order to assist the management of dams upstream in the river basin. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source

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