The Yurungkax River is one of the two major tributaries of the Hotan River that is located at the southern edge of the Tarim River Basin. Its flow is mainly recharged by snow and ice melt water. Since these sources of river flow play an important role in the state of regional water resources, it is necessary to analyze the temporal and spatial variations of snow cover area(SCA) in this catchment for rational water resource management. In this study, we mainly used 8-day snow cover data(MOD10A2) of Moderate Resolution Imaging Spectro-radiometer to extract the SCA of the studied basin over a period of 13 years(March 2000 to February 2013). The two methods used for removing cloud contamination of the SCA images are as follows: MOD/MYD images compositing; and correction using glacier boundary extracted using nine Landsat TM, ETM+ and OLI images from 2000 to 2013. The results show that the two methods removed on average 77.23% of the cloudy pixels and effectively increased the number of images that can be used for analysis. Furthermore, we analyzed the spatial and temporal variations of the SCA in the study area using the corrected MOD10A2 snow cover data, and calculated the coefficients of the Pearson correlation between the SCA and meteorological parameters(air temperature and precipitation) from the hydrological station Tongguziluoke. Results of seasonal change analysis indicate single peak(winter season) of the SCA at low altitude (1650~4000 m asl.) and double peaks(spring and autumn respectively) at high altitude (4000~6000 m asl.), as well as no significant change of the SCA above 6000 m asl. because most areas at this altitude are covered by glaciers. Inter-annual changes of the SCA show that neither the average nor the maximum SCA at all altitude had a significant increasing trend, but the minimum SCA at high altitude increased significantly at a rate of 65.877 km² per year during the study period. The SCA time series analysis shows an increasing-decreasing-increasing trend at all altitudes in spring, summer and winter seasons respectively. But in the autumn, there was no significant fluctuation of the SCA at low altitude except in 2009 and 2010, which were the peak years of the SCA, and the SCA shows an increasing-decreasing trend at high altitude. Pearson correlation coefficients between the SCA and air temperature and precipitation in 8-day interval show that SCA changes are significantly influenced by air temperature and precipitation at low altitude, where air temperature was the dominant factor in the spring and summer, precipitation was the dominant factor in the winter, and air temperature and precipitation equally controlled the SCA regime in the autumn. At high altitude, SCA was sensitive to precipitation only in winter and spring. In the summer SCA was affected by both temperature and precipitation but air temperature was the main factor that influenced SCA.

Wetland as a unique ecosystem has important environment regulating functions and irreplaceable role in maintaining regional ecological balance, conserving biodiversity, and providing food, materials and water resources to humans. The Maqu alpine wetland located in the northeast of the Tibetan Plateau is an important water conserving and supplying area to the upper reach of the Yellow River. In the past 30 years, global warming has led to significant vegetation changes on the Tibetan Plateau. The Maqu alpine wetland is undergoing a process of prominent warming and drying, and degradation of its water conservation function is very significant in recent years. Wetland vegetation dynamics , regional differentiation and causes of degradation of the alpine wetland ecosystem were investigated using multi-source remote sensing data in this study. Land use information and ecological patterns of Maqu were extracted via analyzing Landsat-5/TM and Landsat-7/ETM+ satellite images of 2000 and 2010, through visual interpretation and supervised classification using GIS techniques. NDVI (Normalized Difference Vegetation Index) was used as an indicator in monitoring vegetation changes. MODIS NDVI time series data of 2000-2010(after applying the S-G filtering method and MVC) were used to detect temporal and spatial variations and evolution trend of wetland ecosystems. Point data from weather stations was interpolated using Kriging interpolation method. Based on long-term observations from weather stations，the relationship between Maqu wetland changes and climatic factors(temperature and precipitation) was examined using the least squares method. The results show that areas of rivers, inland beaches, ponds, and swamp meadows were decreasing. Summer NDVI of 2000-2010 in the study area also decreased. Areas with significant decline in NDVI are located in Cairima, Manrima and Hequmachang. Changes in vegetation type also occurred, as signified by swamp meadows shifting to subalpine meadows. The warming and dry climate appears to be a critical factor contributing to the degradation of the Maqu alpine wetland. The changes of the Maqu alpine wetland are related to the inter-annual variability of precipitation and temperature, with 61% and 51% of the total area showing a positive correlation between NDVI and annual precipitation as well as between NDVI and mean temperature respectively. A stronger correlation exists between NDVI and annual precipitation, indicating that the vegetation growth is more sensitive to the inter-annual variability of precipitation.

The term "Ecological Footprint" is used to quantify the pattern of sustainable development in many recent studies. Since this term was coined in 1992, it has gained a growing popularity among scholars and decision makers all over the world because of its operability and comparability across various places. Based on the SCIE (Science Citation Index Expanded) and SSCI(Social Science Citation Index) databases, a bibliometric analysis is conducted on ecological footprint research during 1992-2012. The objective of this study is to identify the status and research direction of this theme. The collaboration relationship on this theme is detected among authors, research institutions, and countries. In addition, differences in research between China, USA and UK is identified. Future trend and hot topics are discussed as well. This study should serve as a useful guidance for beginners to grasp the big picture of this growing literature list while experienced researchers can gain a comprehensive and in-depth overview of this hot topic to better refine research directions and detect the gaps to fill. Bibliometrics is employed in this paper to analyze the publication pattern of ecological footprint research. As a research method used in library and information sciences, bibliometrics has been widely applied to analyze the pattern of literature and trend of a given topic or subject. It can be used for in-depth reviews of research themes for better guidance for follow-up studies. Based on 869 publications indexed in the SCIE/SSCI databases during 1992-2012, the bibliometrics depicts the progress of ecological footprint research through the revisit of many studies in this field. Build upon many review papers on ecological footprint, this bibliometrics-based paper presents a more comprehensive summary of the term definition, computational models, and case studies. The results reveal that the most productive and influential scholar in ecological footprint research is Wackernagel M, a Canadian ecological economist. University of British Columbia and University of Sydney are two major research institutions. Chinese Academy of Sciences and Beijing Normal University are two most influential institutions in this research area in China. USA ranks as the top country in the publications of this topic both qualitatively and quantitatively. China's publications of ecological footprint research follow USA and UK, but the quality should be improved in the future. Despite a relatively smaller size of publications than many other themes, ecological footprint research has witnessed a growing trend by paper number and collaboration across countries. Research has been conducted at multiple scales over the years, with growing interest in analyzing finer-scale patterns and trend. The list of research methods has become richer and more diverse. The methods such as input-output analysis, life cycle assessment and energy analysis are among the most popular approaches in recent literatures, though different countries vary in research focus. Climate change, carbon footprint and the transfer of ecological footprint appear to be the emerging hot topics.