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Liu B.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Qu J.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Qu J.,Gansu Center for Sand Hazard Reduction Engineering and Technology | Kang S.,State Key Laboratory of Cryospheric science
Climate Research | Year: 2016

Four general circulation models (GCMs) under the moderate Representative Concentration Pathway (RCP) 4.5 emission scenario were used to evaluate the impact of climate change on monthly scale dune activity and desertification during the near future (2015-2035) in Anduo on the Tibetan Plateau (TP) of China. Dune activity was estimated by an improved index that uses the Penman-Monteith equation to account for comprehensive climate factors, including precipitation, air temperature, wind speed, humidity, and air pressure. Lower limits were used for the evapotranspiration values and the ratio of rainfall to evapotranspiration so that it was possible to calculate a dune activity index in the cold and dry winter months in the TP. The GCM outputs were transferred by statistical functions built from the control period (1966-2005), and the overlapping period of GCM projections and observations from 2006-2014 was used for error estimation. The results show that all GCMs captured the variation in dune activity well, although large differences in values were found. The statistical transferring of GCM outputs cannot reduce estimation error. The annual dune activity index is predicted to decrease by 7 to 9% during 2015-2035, implying that sand dunes will be easily stabilized in the future, but the 4 GCMs differ in January and February. If excessive surface disturbances can be controlled, the future environment in the studied area will be suitable for the reversal of the desertification trend, recovery of degraded land, and improvement of the living conditions for local herders. © 2016 The authors. Source

Wu H.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Wu H.,University of Chinese Academy of Sciences | Wang N.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Wang N.,State Key Laboratory of Cryospheric science | And 3 more authors.
Annals of Glaciology | Year: 2014

Water level fluctuations of inland lakes are related to regional-scale climate changes, and reflect variations in evaporation, precipitation and glacier meltwater flowing into the lake area in its catchment. In this paper, Ice, Cloud and land Elevation Satellite (ICESat) altimeter data and Landsat imagery (2002-09) are used to estimate Nam Co lake (Nyainqentanglha range, Tibetan Plateau) water elevation changes during 2002-09. In 2003 Nam Co lake covered an area of ~1998.8±4.2km2 and was situated at 4723ma.s.l. Over such inland water bodies, ICESat altimeter data offer both wide coverage and spatial and temporal accuracy. We combine remote-sensing and GIS technology to map and reconstruct lake area and increased volume changes during a 7 year time series. Nam Co lake water level increased by 2.4±0.12m (0.33ma-1) between 23 February 2003 and 1 October 2009, and lake volume increased by 4.9±0.5km3. In the past 7 years, Nam Co lake area has increased from 1998.78±5.4 to 2023.8±3.4km 2, the glacier-covered area has decreased from 832.34 to 821.0km 2 and the drainage basin area has decreased from 201.1±4.2 to 196.1±2.3km2. However, the most spectacular feature is the continual water level rise from 2003 to 2009 without an obvious associated increase in precipitation. Based on digital elevation models (DEMs) from Shuttle Radar Topography Mission (SRTM) DEM data and corrected ICESat elevation data, significant changes to glacier mass balance in the western Nyainqentanglha mountains are indicated. Nyainqentanglha mountain glacier surface elevations decreased by 8.39±0.45m during 2003-09. Over the same period, at least 1.01km3 of glacial meltwater flowed into Nam Co lake, assuming a glacial runoff coefficient of 0.6. The mean glacier mass-balance value is -490mmw.e. over the corresponding period, indicating that glacier meltwater in the catchment contributes to lake level rise. The contribution rate of glacial meltwater to lake water volume rise is 20.75%. The temporal lake level fluctuation correlates with temperature variations over the same time span. Source

Wei T.,Chinese Academy of Meteorological Sciences | Ding M.,Chinese Academy of Meteorological Sciences | Ding M.,State Key Laboratory of Cryospheric science | Wu B.,Chinese Academy of Meteorological Sciences | And 2 more authors.
Atmospheric Science Letters | Year: 2016

We present a comprehensive analysis of temperature-related extreme events in Ny-Ålesund (78.9°N, 11.9°E) using data from three meteorological stations. The results show that annual mean temperatures in Ny-Ålesund increase at a rate that is four times faster than the global mean from 1975 to 2014 with no 'hiatus' in recent decades. The annual diurnal temperature range shows a negative trend as minimum daily temperature increases at a faster rate than maximum daily temperature. A negative trend in cold extremes and a positive trend in warm extremes are observed. This asymmetry hints at potential changes in the probability distribution of temperatures in Ny-Ålesund. © 2016 Royal Meteorological Society. Source

Yang G.,Key Laboratory of Ecohydrology and Integrated River Basin Management | Yang G.,State Key Laboratory of Cryospheric science | Ye B.,State Key Laboratory of Cryospheric science | Xie X.,Key Laboratory of Ecohydrology and Integrated River Basin Management | Zhou L.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2010

Oasis is a specific landscape that exists with deserts in arid regions. In this paper, the oasis landscape changes in middle-lower reaches of Shule River basin had been analyzed. Using the Landsat TM imagines of June in 1987 and August in 2003 as the digital sources, the vector and grid landscape maps of distributions of the study area were derived. The dynamics variation of the oasis landscape in that basin was got on the basis of the software of ArcGIS 9.0, and the forecast on the dynamic variation of landscapes was executed using the software of the Matlab 6.3. At the same time, the eco-environmental effects of landscape change had been analyzed. The results showed that the landscape change with the main feature of increasing cropland area led to a series of ecological environment problem, such as deterioration of water quality, natural vegetation decreasing, and the eco-environmental system deteriorating. Human activities, especially in relation to water utilization and population increment, have gradual became the most active and dominant driving factors in the landscape change. © 2010 IEEE. Source

Wu H.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Wu H.,University of Chinese Academy of Sciences | Wu H.,State Key Laboratory of Cryospheric science | Wang N.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 5 more authors.
Journal of Applied Remote Sensing | Year: 2014

The Ice, Cloud and land Elevation Satellite (ICESat) altimetry and the Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) data are used to estimate glacier mass loss changes in the West Kunlun Mountains, Tibetan Plateau (TP), 2003 to 2009. We integrated Landsat thematic mapper (TM)/enhanced TM images and GIS spatial analysis to map glacier surface elevation changes during 2003 to 2009. The ICESat-GLAS data can be used as baselines for surface elevation changes in altimetry as well as for TM imagery changes for depicting glacier area. Least-squares regression of an ICESat-derived thickness series shows the regional glacier mass decreased at an average rate of 1.41±0.23 km3/year water equivalent from 2003 to 2009, during the period of 2003 to 2009, the trend in thickness change became weaker. The ICESat-GLAS and SRTM DEM elevation differences between February 2003 and October 2009 show that the glacier surface elevations were decreasing below 5800 m but increased by 1.1±0.7 m above 6000 m a.s.l. region over that period. Thickness changes in the lower reaches of the glaciers indicate that the glacier ice ablation was mainly due to the summer temperature increases of 0.23°C and the summer precipitation decreases of 47.8 mm as measured at four stations, as well as the effects of sand and dust sources from the Tarim Basin. Meanwhile, in the upper parts of the glaciers (above 5800 m a.s.l.), ice surface elevation was increasing even though the Hetian station summer temperature at the 500 hPa level showed an obvious decrease of 0.78°C compared to 2003. In the upper part of the glacier-covered region, firn compaction and surface density should be taken into account. The glacier surges and bedrock movement may also lead to an underestimate of the volume loss due to the reduced mass conversion. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE). Source

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