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Land use dynamics in Lhasa area, Tibetan Plateau

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Journal of Geographical Sciences 2010年第6期20卷 899-912页

作者： CHU DUO ZHANG Yili BIANBA Ciren liu linshan Tibet Institute of Plateau Atmospheric and Environmental Sciences CMA Lhasa 850000 China Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China

Land use change is the result of the interplay between socioeconomic, institutional and environmental factors, and has important impacts on the functioning of socioeconomic and environmental systems with important tradeoffs for sustainability, food security, biodiversity and the vulnerability of people and ecosystems to global change impacts. Based on the results of the First Land Use Survey in Tibet Autonomous Region carried out in the late 1980s land use map of Lhasa area in 1990 was compiled for the main agricultural area in Lhasa valley using aerial photos obtained in April, May and October 1991 and Landsat imagery in the late 1980s and 1991 as remotely sensed data sources. Using these remotely sensed data the land use status of Lhasa area in 1991, 1992, 1993, 1995, 1999 and 2000 were mapped through updating annual changes of cultivated land, artificial forest, grass planting, grassland restoration, and residential area and so on. Land use map for Lhasa area in 2007 was made using ALOS AVNIR-2 composite images acquired on October 24 and December 26, 2007 through updating changes of main land use types. According to land use status of Lhasa area in 1990, 1995, 2000 and 2007, the spatial and temporal land use dynamics in Lhasa area from 1990 to 2007 are further analyzed using GIS spatial models in this paper.

关键词： land use change Lhasa area Tibetan Plateau

Predicting Potential Distribution of Tibetan Spruce (Picea smithiana) in Qomolangma (Mount Everest) National Nature Preserve Using Maximum Entropy Niche-based Model

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Chinese Geographical Science 2011年第4期21卷 417-426页

作者： ZHANG Jiping ZHANG Yili liu linshan NIE Yong Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

Tibetan spruce (Picea smithiana) is an endemic species of the Himalayas,and it distributes only in a re-stricted area with very low number.To address the lack of detailed distributional information,we used maximum en-tropy (Maxent) niche-based model to predict the species' potential distribution from limited occurrence-only records.The location data of P.smithiana,relative bioclimatic variables,vegetation data,digital elevation model (DEM),and the derived data were analyzed in Maxent.The receiver operating characteristic (ROC) curve was applied to assess the prediction accuracy.The Maxent jackknife test was performed to quantify the training gains from data layers and the response of P.smithiana distribution to four typical environmental variables was analyzed.Results show that the model performs well at the regional scale.There is a potential for continued expansion of P.smithiana population numbers and distribution in China.P.smithiana potentially distributes in the lower reaches of Gyirong Zangbo and Poiqu rivers in Gyirong and Nyalam counties in Qomolangma (Mount Everest) National Nature Preserve (QNNP),China.The species prefers warm temperate climate in mountain area and mainly distributes in needle-leaved evergreen closed to open forest and mixed forest along the river valley at relatively low altitudes of about 2000-3000 m.Model simulations suggest that distribution patterns of rare species with few species numbers can be well predicted by Max-ent.

关键词：国家级自然保护区模型预测珠穆朗玛峰最大熵云杉珠峰基础西藏

Glacial change in the vicinity of Mt. Qomolangma （Everest）, central high Himalayas since 1976

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Journal of Geographical Sciences 2010年第5期20卷 667-686页

作者： NIE Yong ZHANG Yili liu linshan ZHANG Jiping Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Glaciers are one of the most important land covers in alpine regions and especially sensitive to global climate change. Remote sensing has proved to be the best method of investigating the extent of glacial variations in remote mountainous areas. Using Landsat thematic mapping （TM） and multi-spectral-scanner （MSS） images from Mt. Qomolangma （Everest） National Nature Preserve （QNNP）, central high Himalayas for 1976, 1988 and 2006 we derived glacial extent for these three periods. A combination of object-oriented image interpretation methods, expert knowledge rules and field surveys were employed. Results showed that （1） the glacial area in 2006 was 2710.17 ＋ 0.011 km2 （about 7.41% of the whole study area）, and located mainly to the south and between 4700 m to 6800 m above sea level; （2） from 1976 to 2006, glaciers reduced by 501.91± 0.035 km2 and glacial lakes expanded by 36.88 ＋ 0.035 kin2; the rate of glacier retreat was higher in sub-basins on the southern slopes （16.79%） of the Himalayas than on the northern slopes （14.40%）; most glaciers retreated, and mainly occurred at an elevation of 4700-6400 m, and the estimated upper limit of the retreat zone is between 6600 m and 6700 m; （3） increase in temperature and decrease in precipitation over the study period are the key factors driving retreat.

关键词： glacial change glacial retreat Himalayas Mt. Qomolangma （Everest） National Nature Preserve remote sensing

Sensitivity of surface air temperature change to land use/cover types in China

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Science China Earth Sciences 2009年第8期52卷 1207-1215页

作者： YANG XuChao ZHANG YiLi liu linshan ZHANG Wei DING MingJun WANG ZhaoFeng Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Institute of Meteorological Sciences Meteorological Bureau of Zhejiang ProvinceHangzhou 310017China Shanghai Institute of Geological Survey Shanghai 200072China

Using CRU high resolution grid observational temperature and ERA40 reanalysis surface air temperature data during 1960-1999, we investigated the sensitivity of surface air temperature change to land use/cover types in China by subtracting the reanalysis from the observed surface air temperature (observation minus reanalysis, OMR). The results show that there is a stable and systemic impact of land use/cover types on surface air temperature. The surface warming of each land use/cover type reacted differently to global warming. The OMR trends of unused land (≥0.17℃/decade), mainly comprised by sandy land, Gobi and bare rock gravel land, are obviously larger than those of the other land use/cover types. The OMR over grassland, farmland and construction land shows a moderate decadal warming about 0.12℃ /decade, 0.10℃/decade, 0.12 ℃ /decade, respectively. Woodland areas do not show a significant warming trend (0.06 ℃ /decade). The overall assessment indicates that the surface warming is larger for areas that are barren and anthropogenically developed. The better the vegetation cover, the smaller the OMR warming trend. Responses of surface air temperature to land use/cover types with similar physical and chemical properties and biological processes have no significant difference. The surface air temperature would not react significantly until the intensity of land cover changes reach a certain degree. Within the same land use/cover type, areas in eastern China with intensive human activities exhibit larger warming trend. The results provide observational evidence for modeling research on the impact of land use/cover change on regional climate. Thus, projecting further surface climate of China in regional scale should not only take greenhouse gas increase into account, but also consider the impact of land use/cover types and land cover change.

关键词： surface air temperature land use/cover types OMR method observations reanalysis

Vegetation change in the Mt. Qomolangma Nature Reserve from 1981 to 2001

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Journal of Geographical Sciences 2007年第2期17卷 152-164页

作者： ZHANG Wei ZHANG Yili WANG Zhaofeng DING Mingjun YANG Xuchao LIN Xuedong liu linshan Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China Institute of Tibetan Plateau Research CAS Beijing 100085 China

Based on the NOAA AVHRR-NDVI data from 1981 to 2001, the digitalized China Vegetation Map （1：1,000,000）, DEM, temperature and precipitation data, and field investigation, the spatial patterns and vertical characteristics of natural vegetation changes and their influencing factors in the Mt. Qomolangma Nature Reserve have been studied. The results show that：（1） There is remarkable spatial difference of natural vegetation changes in the Mt. Qomolangma Nature Reserve and stability is the most common status. There are 5.04% of the whole area being seriously degraded, 13.19% slightly degraded, 26.39% slightly improved, 0.97% significantly improved and 54.41% keeping stable. The seriously and slightly degraded areas, which mostly lie in the south of the reserve, are along the national boundaries. The areas of improved vegetation lie in the north of the reserve and the south side of the Yarlung Zangbo River. The stable areas lie between the improved and degraded areas. Degradation decreases with elevation. （2） Degeneration in the Mt. Qomolangma Nature Reserve mostly affects shrubs, needle-leaved forests and mixed forests. （3） The temperature change affects the natural vegetation changes spatially while the integration of temperature changes, slopes and aspects affects the natural vegetation change along the altitude gradients. （4） It is the overuse of resources that leads to the vegetation degeneration in some parts of the Mt. Qomolangma Nature Reserve.

关键词： Mt. Qomolangma （Everest） nature reserve AVHRR vegetation degradation Himalayas

Characteristics of grassland degradation and driving forces in the source region of the Yellow River from 1985 to 2000

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Journal of Geographical Sciences 2006年第2期16卷 131-142页

作者： liu linshan ZHANG Yili BAI Wanqi YAN Jianzhong Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China College of Resources and Environment Southwest University Chongqing 400716 China Peking University Beijing 100871 China

The source region of the Yellow River is located in the middle east of the Tibetan Plateau in northwest China. The total area is about 51,700 km^2, mainly covered by grassland （79%）, unused land （16%） and water （4%）. The increasing land utilization in this area has increased the risk of environmental degradation. The land use/cover data （1985 and 2000） provided by the Data Center of Resources and Environment in the Chinese Academy of Sciences were used to analyze the land cover change in the source region of the Yellow River. DEM （1：250,000） data, roads and settlement data were used to analyze the spatial characteristics of grasslands degradation. The ArcGIS 9 software was used to convert data types and do the overlay, reclassification and zonal statistic analysis. Results show that grassland degradation is the most important land cover change in the study area, which occupied 8.24% of the region＇s total area. Human activities are the main causes of the grassland degradation in the source region of the Yellow River： 1） the degradation rate is higher on the sunny slope than on the shady slope; 2） the grassland degradation rate decreases with an increase in the elevation, and it has a correlation coefficient of -0.93; 3） the nearer to the settlements the grassland is, the higher the degradation rate. Especially within a distance range of 12 km to the settlements, the grassland degradation rate is highly related with the distance, with a coefficient of -0.99; and 4） in the range of 4 km, the degradation rate decreases with the increase of distance to the roads, with a correlation coefficient of -0.98. Besides some physical factors, human activities have been the most important driving forces of the grassland degradation in the source region of the Yellow River since 1985. To resolve the degradation problems, population control is essential, and therefore, it can reduce the social demand of livestock products from the grassland. To achieve sustainable development, it needs to improve the management of grassland ecosy

关键词： source region of the Yellow River grassland degradation slope aspect elevation distance settlement roads

The trend on runoff variations in the Lhasa River Basin

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Journal of Geographical Sciences 2008年第1期18卷 95-106页

作者： LIN Xuedong ZHANG Yili YAO Zhijun GONG Tongliang WANG Hong CHU Duo liu linshan ZHANG Fei Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Institute of Tibetan Plateau Research CAS Beijing 100085 China Tibet Hydroelectric Investigation Designed Research Institute Lhasa 850000 China Department of Hydraulic Engineering Tsinghua University Beijing 100084 China Tibet Hydrographic and Water Resources Survey Bureau Lhasa 850000 China Institute of Xizang-Plateau Atmosphere Environment Sciences Lhasa 850000 China

Taking the Lhasa River Basin above Lhasa hydrological station in Tibetan Plateau as a study area, the characteristics of the annual and monthly mean runoff during 1956-2003 were analyzed, based on the hydro-data of the two hydrological stations （Lhasa and Tanggya） and the meteorological data of the three meteorological stations （Damxung, Lhasa and Tanggya）. The trends and the change points of runoff and climate from 1956 to 2003 were detected using the nonparametric Mann-Kendall test and Pettitt-Mann-Whitney change-point statistics. The correlations between runoff and climate change were analyzed using multiple linear regression. The major results could be summarized as follows：（1） The annual mean runoff during the last 50 years is characterized by a great fluctuation and a positive trend with two change points （around 1970 and the early 1980s）, after which the runoff tended to increase and was increasing intensively in the last 20 years. Besides, the monthly mean runoff with a positive trend is centralized in winter half-year （November to April） and some other months （May, July and September）. （2） The trends of the climate change in the study area are generally consistent with the trend of the runoff, but the leading climate factors which aroused the runoff variation are distinct. Precipitation is the dominant factor influencing the annual and monthly mean runoff in summer half year, while temperature is the primary factor in winter season.

关键词： Lhasa River Basin trend of runoff variation Pettitt change-point test Mann-Kendall trend analysis multiple linear regressions

The international conference on mountain development in a context of global change with special focus on the Himalayas was held successfully in Kathmandu, Nepal

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Journal of Geographical Sciences 2018年第10期28卷 1560-1560,F0003页

作者： XIN Liangjie liu linshan

The international conference on mountain development in a context of global change with special focus on the Himalayas was held in Kathmandu, Nepal on April 21-26.

关键词： The international conference on mountain development in a context of global change with special focus on the Himalayas was held successfully in Kathmandu Nepal

Start of vegetation growing season on the Tibetan Plateau inferred from multiple methods based on GIMMS and SPOT NDVI data

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Journal of Geographical Sciences 2015年第2期25卷 131-148页

作者： DING Mingjun LI Lanhui ZHANG Yili SUN Xiaomin liu linshan GAO Jungang WANG Zhaofeng LI Yingnian Key Lab of Poyang Lake Wetland and Watershed Research of Ministry of Education and School of Geography and Environment Jiangxi Normal University Nanchang 330022 China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research (IGSNRR) CAS Beijing 100101 China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 10101 China Key Laboratory of Ecosystem Network Observation and Modeling IGSNRR CAS Beijing 100101 China Northwest Institute of Plateau Biology CAS Xining 810008 China

In this study, we have used four methods to investigate the start of the growing season （SGS） on the Tibetan Plateau （TP） from 1982 to 2012, using Normalized Difference Vegetation Index （NDVI） data obtained from Global Inventory Modeling and Mapping Studies （GIMSS, 1982-2006） and SPOT VEGETATION （SPOT-VGT, 1999-2012）. SGS values esti- mated using the four methods show similar spatial patterns along latitudinal or altitudinal gradients, but with significant variations in the SGS dates. The largest discrepancies are mainly found in the regions with the highest or the lowest vegetation coverage. Between 1982 and 1998, the SGS values derived from the four methods all display an advancing trend, however, according to the more recent SPOT VGT data （1999-2012）, there is no continu- ously advancing trend of SGS on the TP. Analysis of the correlation between the SGS values derived from GIMMS and SPOT between 1999 and 2006 demonstrates consistency in the tendency with regard both to the data sources and to the four analysis methods used. Com- pared with other methods, the greatest consistency between the in situ data and the SGS values retrieved is obtained with Method 3 （Threshold of NDVI ratio）. To avoid error, in a vast region with diverse vegetation types and physical environments, it is critical to know the seasonal change characteristics of the different vegetation types, particularly in areas with sparse grassland or evergreen forest.

关键词： phenology NDVI start of vegetation growing season method Tibetan Plateau