High precision topographic data on Lop Nor basin＇s Lake ＂Great Ear＂ and the timing of its becoming a dry salt lake

High precision elevation measurements using DGPS were carried out along three representative tran-sects for the ＂Great Ear＂ area, a dry salt lake within the Lop Nor basin. Results indicate that the Lop Nor basin is only 5.2 m deep and its lowest point occurs at the center of the ＂Great Ear＂. In addition, the basin is asymmetric-steeper in the southwest （0.19‰） and gentler in the northeast （0.09‰）. Points along the same ＂Great Ear＂ ring were found to have an identical elevation value, but different when from different ones （lower towards the center）. The spacing of the ＂Great Ear＂ rings was found to be closely related with the surface steepness. The closer the ＂Great Ear＂ rings are spaced, the steeper the ground surface, and vice versa. These findings support the argument that the ＂Great Ear＂ rings are the former shoreline trails left behind by Lop Nor water during the last few episodes of recession towards its total dry up. A comprehensive analysis of the high precision elevation data, historical accounts, aerial and satellite photographs and imagery, and official topographic maps of the study area suggests that the ＂Great Ear＂ area in the Lop Nor basin was incorrectly mapped as being covered by a great body of water on the 1963 topographic maps. A re-interpretation of the 1958 aerial photographs and newer remote sensing imagery indicated that the ＂Great Ear＂ ring structure was already in place in 1958 and it continued to appear on the subsequent remote sensing data without any major changes. It is estimated that lake water in the ＂Great Ear＂ area of the Lop Nor basin disappeared between the late 1930s and early 1940s.     

Estimation of the rational water area for controlling wind erosion in the dried-up basin of the Ebinur Lake and its effect detection

The Ebinur Lake region was described as a ＂Green Labyrinth＂ in ＂Xinjiang Map Records： Records of Rivers＂ published in 1910, however, the ecology and environment in the region have been seriously degenerated due to the impacts of human activities during the recent 40 years. A dried-up lake basin with an area of 107.4 km^2 forms in its northwestern part, is covered by unconsolidated silt deposit without vegetation, and has become one of the main dust sources of dust weathers in north Xinjiang, and the dust with an annual amount of 4.8×10^6 t is blown out of the region by strong winds from the Alataw mountain-gap where there are 164 days occurring strong winds in a year. The rational water area and inflow of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin are estimated using the water balance equation after analyzing the current ecological problems and the relationship between the granular composition of deposit in the dried-up lake basin and the dust weathers, and the ecological effects in recent years are monitored. It is considered that the water area of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin should be 800 km^2at least, and the annual volume of surface runoff and groundwater recharging the lake should be over 7.92×10^8 m^3.     

Estimation of the rational wa-ter area for controlling wind erosion in the dried-up basin of the Ebinur Lake and its effect detection

The Ebinur Lake region was described as a “Green Labyrinth” in “Xinjiang Map Records: Records of Rivers” published in 1910, however, the ecology and environment in the region have been seriously degenerated due to the impacts of human activities during the recent 40 years. A dried-up lake basin with an area of 107.4 km² forms in its northwestern part, is covered by unconsolidated silt deposit without vegetation, and has become one of the main dust sources of dust weathers in north Xinjiang, and the dust with an annual amount of 4.8×10⁶ t is blown out of the region by strong winds from the Alataw mountain-gap where there are 164 days occurring strong winds in a year. The rational water area and inflow of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin are estimated using the water balance equation after analyzing the current ecological problems and the relationship be-tween the granular composition of deposit in the dried-up lake basin and the dust weathers, and the ecological effects in recent years are monitored. It is considered that the water area of the Ebinur Lake for improving the ecology in the lake region and effec-tively controlling wind erosion in the dried-up lake basin should be 800 km² at least, and the annual volume of surface runoff and groundwater recharging the lake should be over 7.92×10⁸ m³.     

Monitoring lake changes of Qinghai-Tibetan Plateau over the past30 years using satellite remote sensing data

During the years 2006–2009,lakes in the Qinghai-Tibetan Plateau(QTP)were investigated using satellite remote sensing strategies.We report the results of this investigation as well as follow-up research and expanded work.For the investigation,we mainly focused on lakes whose areas are more than 1 km2.The remote sensing data that we used included 408 scenes of CBERS CCD images and 5 scenes of Landsat ETM?images in Qinghai Province and Tibet Autonomous Region.All these data were acquired around years 2005–2006.Besides remote sensing images,we also collected 1,259 topographic maps.Numbers and areas of lakes were analyzed statistically,which were then compared with those coming from the first lake investigation(implemented between the1960s and 1980s).According to our investigation,up to and around year 2005–2006,the total number of lakes in the QTP was 1,055(222 in Qinghai and 833 in Tibet),accounting for more than 30%of that of China.Thirty newborn lakes with area[1 km2were found,and 5 dead lakes with initial area[1 km2were also found.Among those 13 big lakes([500 km2),Yamzhog Yumco had seriously shrunk,and it has continued to shrink in recent years;Qinghai Lake had shrunk during the period,but some new researches indicated that it has been expanding since the year 2004;Siling Co,Nam Co,and Chibuzhang Co had expanded in the period.We divided the newborn lakes into six categories according to their forming reasons,including river expansion,wetland conversion,etc.The changes of natural conditions led to the death of four lakes,and human exploitation was the main reason for the death of Dalianhai Lake in Qinghai.We picked out three regions which were sensitive to the change of climate and ecological environment:Nagqu Region,Kekexili Region,and the source area of the Yellow River(SAYR).Lakes in both Nagqu and Kekexili have been expanded;meanwhile,most lakes in the SAYR have obviously been shrunk.These regional patterns of lake changes were highly related to variations of temperature,glacier,precipitation,and evaporation.Our investigation and analysis will provide references for researches related to lake changes in the QTP and the response to climate fluctuations.     

Lakes’ state and abundance across the Tibetan Plateau

Understanding the changes in number and areal extent of lakes,as well as their abundance and size distribution is important for assessments of regional and global water resources,biogeochemical cycles,and changes in climate.In this study,changes in lake area greater than 1 km2are mapped using Landsat datasets,spanning the 1970s,1990,2000,and 2010.In addition,high-resolution images(GeoCover Landsat mosaic 2000,with a pixel size of 14.25 m)are used for the first time to map lakes as small as 0.001 km2across the entire Tibetan Plateau(TP).Results show that the numbers and areal extent of individual lakes[1 km2in size show a slight decrease between the 1970s and 1990,followed by a clear increase from 1990 to 2010.Ninety-nine new lakes are identified between the 1970s and 2010,71 of which are found between 1990 and 2010.This indicates the accelerated glacier melt and/or increased difference of precipitation minus evaporation since the 1990s.More than 80%of the lakes show an increase in their area between the 1970s and2010.The lake census,using 2000 imagery,shows that there are 32,843 lakes with a total area of 43,151.08±411.49 km2,which makes up 1.4%of the total area of the TP.Around 96%of all lakes are small,with an area\1 km2,while the 1,204 large lakes([1 km2)account for96%of the total lake area.The TP is subdivided into 12greater drainage basins,and of these the inner TP dominates in terms of the number of lakes(55.03%),the total area of lakes(66%),and lake density(0.026/km2compared to the mean,0.011/km2).A plot of lake abundance against size shows that the size distribution of lakes departs from a typical power-law distribution,but displays such a distribution at the mean elevation(4,715 m),with an r2value of 0.97 and a slope of-0.66.The slopes of the abundance-size equations from each of the 12 greater basins,and from all basins together,are larger than-1,supporting the inference that larger lakes,rather than the small lakes,contribute more to the total lake surface area across the TP.The lake inventory provided in this study,along with the assessment of lake size distribution,have important implications for estimates of water balance,for water resource management,and for lake area estimations in the TP.     

Land use and land cover change along the topographic gradients and stream corridors in the LRGR

With the Longitudinal Range-Gorge Region （LRGR） in the southwestern China as the object, this research studied how land use pattern varies with the complex topographic features. Based on the 1：50000 digital elevation model （DEM） data and the remote sensing images in 1980, 2001, and by using GIS map algebra method, we investigated the relationship between landform （e.g. elevation and stream networks） and land use, especially the correlation of human activities with the spatial arrangement of the stream networks. This paper reveals that land use and land cover changes in valleys with rich water source at lower elevations are characterized by distinct successional gradients from the river to the upland, which was possibly due to the distance and the availability of water resource. And by dividing the region into four vertical zones according to their elevations, we found that the land use and human activities in each zone were significantly different. Finally, it is indicated that the jamming effects of human activities in the LRGR were spatially heterogeneous and thus led to the barrier effect of stream corridors.     

Monitoring the frozen duration of Qinghai Lake using satellite passive microwave remote sensing low frequency data

The Qinghai Lake is the largest inland lake in China. The significant difference of dielectric properties between water and ice suggests that a simple method of monitoring the Qinghai lake freeze-up and break-up dates using satellite passive microwave remote sensing data could be used. The freeze-up and break-up dates from the Qinghai Lake hydrological station and the MODIS LIB reflectance data were used to validate the passive microwave remote sensing results. The validation shows that passive microwave remote sensing data can accurately monitor the lake ice. Some uncertainty comes mainly from the revisit frequency of satellite overpass. The data from 1978 to 2006 show that lake ice duration is reduced by about 14--15 days. The freeze-up dates are about 4 days later and break-up dates about 10 days earlier. The regression analyses show that, at the 0.05 significance level, the correlations are 0.83, 0.66 and 0.89 between monthly mean air temperature （MMAT） and lake ice duration days, freeze-up dates, break-up dates, respectively. Therefore, inter-annual variations of the Qinghai Lake ice duration days can significantly reflect the regional climate variation.     

Recent glacial retreat and its effect on water resources in eastern Xinjiang

The eastern Xinjiang Basin is desperately short of water. Most rivers in the basin originate in the high eastern Tianshan, which has abundant precipitation and numerous alpine glaciers. Fieldwork conducted on three reference glaciers around Mt. Bogda in 1981 and 2009 suggests that they all strongly melt in summer, a process that has tended to accelerate in recent decades. Based on topographic maps from 1962 and 1972 and 2005/2006 satellite imagery, we investigated 203 glaciers near Mt. Bogda and 75 glaciers near Mt. Harlik. The results show that the surface area of the Mt. Bogda glaciers decreased by 21.6% (0.49% a?1) from 1962 to 2006. This was accompanied by a 181 m decrease in length and a 28% drop in ice volume. In the Mt. Harlik region, areal extent was reduced by 10.5% (0.32% a?1), length by 166 m, and volume by 14% between 1972 and 2005. South-facing glaciers lost more of their area than those that are north facing, yielding an areal loss of 25.3% and 16.9% for southern and northern slopes of Mt. Bogda, respectively, and 12.3% and 6.6% for the comparable slopes of Mt. Harlik. Glaciers smaller than 0.5 km2 in area experienced the strongest retreat, whereas glaciers larger than 2 km2 in area experienced gentle recession but may be the main contributors in the future to river runoff. Glacial ablation in eastern Xinjiang tends to be strong, and the water resources in this region are deteriorating. Also, a heavy reduction in the capacity of the local karez system, as well as a significant change in river runoff, can be related to glacial retreat. Combined, this will adversely affect the downstream city of Urumqi and the Turfan Basin.     

Extracting change information of land use and soil erosion based on RS & GIS technologystration

Rapid landuse change has taken place in many arid regions of China such as Yulin prefecture over the last decade due to rehabilitation measures. Landuse change and soil erosion dynamics were investigated by the combined use of remote sensing and geographic information systems (GIS). The objectives were to determine landuse transition rates and soil erosion change in Yulin prefecture over 15 years from 1986 to 2000. Significant changes in landuse and soil erosion occurred in the area over the study period. The results show the significant decrease in barren land mainly due to conversion to grassland. Agricultural land increased associated with conversions from grassland and barren land. The area of water erosion and wind erosion declined. The study demonstrates that the integration of satellite remote sensing and GIS is an effective approach for analyzing the direction, rate, and spatial pattern of landuse and soil erosion change.     

Monitoring dynamic changes of global land cover types:fluctuations of major lakes in China every 8 days during 2000–2010

Remote sensing images can be used to delineate variations in the area of lakes and to assess the influence of environmental changes and human activities.However,because lakes are dynamic,results obtained from individual images acquired on a single date are not representative and do not accurately reflect ongoing changes.In this study,we used 8-day moderate resolution imaging spectroradiometer(MODIS)composite data from 2000 to2010 to map water surface changes over 629 lakes in China.We combined automatic extraction of training data and support vector machine classification to derive the spatial distribution of these large water bodies.The producer’s and user’s accuracies for MODIS images were91.06%and 89.81%,respectively,when compared with interpretation results from 30 m resolution Landsat images taken on similar days.Area changes,variability,inundation intensity,and rainy seasons of the 629 lakes were analyzed based on this multi-temporal lake database.The total area of the 629 lakes increased over the study period,primarily as a result of the expansion of lake areas on the Tibetan Plateau.There were 12 lakes with a maximum area[1,000 km2,and six of these decreased in area from 2000to 2010.The shrinkages of Poyang Lake and Dongting Lake were-54.76 and-25.08 km2/a,respectively.The area of lakes on Tibetan Plateau,in northern Xinjiang,northeastern Inner Mongolia,and northeastern China varied little,while lakes on the Yangtze Plain,in southern Inner Mongolia,and central Xinjiang fluctuated considerably.Inundation intensity increased for lakes on the Tibetan Plateau,in northern Xinjiang,Heilongjiang,and Jilin,while inundation extent decreased in central Xinjiang,southern Tibet,southern Inner Mongolia,Sichuan,and on the Yangtze Plain.This study is an attempt to develop high-frequency specific land cover maps to improve applicability of general land cover maps.The lake products serve as an important supplement to hydrologic data.The lake database enables the generation of new land surface process models,which could improve the precision of simulations,based on more accurate observations of dynamic lake systems.     

Physically based simulation of Buddha Glory

This paper proposes a novel method of photorealistic simulation of Buddha Glory, a natural phenomenon of great visual beauty which can be observed in the area of famous Buddhism Holy Lands in China. This phenomenon is mainly caused by back-scattering of water droplets in fog or cloud. To simulate the glory, we first calculate the spectral scatter intensity of glory rings using Mie scattering theory. We then present a new shadow model to determine the deformed shape of the head and body of “Buddha” within the glory ring. The affect of atmospheric parameters such as the solar elevation angles, the density and size of water droplet in fog or cloud on the shape and color of Buddha Glory is also calculated. For rendering, we adopt the method of path scattering integral to generate the whole attenuated scene of Buddha Glory. Compared with the photographs of real Buddha Glory displays, our synthetic results are quite satisfactory.     

Hydrochemical characteristics and recharge sources of Lake Nuoertu in the Badain Jaran Desert

We present a case study of physical and chemical indicators and isotope characteristics of Lake Nuoertu,one of the largest and deepest lakes of the Badain Jaran Desert.We analyze the concentrations of eight ions,total dissolved solids,and stable isotope composition of the lake and groundwater,as well as radioactive isotope tritium concentration in groundwater.The results show that annual and seasonal variations of the physical and chemical characteristics of Lake Nuoertu water are significantly greater than those of groundwater.The lake is uniformly mixed in the horizontal and vertical directions,and the hydrochemical types of the lake at different depths are consistent for Na–Cl–CO3–(SO4).Stable isotope composition of the lake and groundwater at Nuoertu is distributed along the local evaporation line(EL)slope,which is less than the slope of the global meteoric water line.The comparatively small slope shows the characteristic strong evaporation in the study area.Lake water isotopes are mostly in the upper right corner of the EL,whereas groundwater is mostly in the lower left corner.The main recharge source of Nuoertu lake water is groundwater,in combination with lake water and groundwater level change.The age of tufa springs around Nuoertu is about75–80 a,which shows that the initial recharge source of the lake is a mix between modern and 1952 or older;however,further research is required.     

Geochemical characteristics and zones of surface snow on east Antarctic Ice Sheet

The surface-snow geochemical characteristics are discussed on the East Antarctic Ice Sheet, depending on the stable isotopes ratios of oxygen and hydrogen, concentration of impurities (soluble-ions and insoluble micro-particle) in surface snow collected on the ice sheet. The purpose is to study geochemical zones on the East Antarctic Ice Sheet and to research sources and transportation route of the water vapor and the impurities in surface snow. It has been found that the ratio coefficients, as S1, d1 in the equation δD =S1δ^18O d1, are changed near the elevation 2000 m on the ice sheet. The weight ratio of Cl^-/Na^ at the area below the elevation of 2000 m is close to the ratio in the sea salt; but it is about 2 times that of the sea salt, at the inland area up to the elevation of 2000 m. The concentrations of non-sea-salt Ca^2 ion (nssCa^2 ) and fine-particle increase at the interior up to the elevation 2000 m. At the region below the elevation of 2000 m, the impurity concentration is decreasing with the elevation increasing. Near coastal region, the surface snow has a high concentration of impurity, where the elevation is below 800 m. Combining the translating processes of water.vapor and impurities, it suggests that the region up to the elevation 2000 m is affected by large-scale circulation with longitude-direction, and that water-vapor and impurities in surface snow come from long sources. The region below the elevation 2000 m is affected by some strong cyclones acting at peripheral region of the ice sheet, and the sources of water and impurities could be at high latitude sea and coast. The area below elevation 800 m is affected by local coastal cyclones.     

Remote sensing of environmental change over China: A review

China is a large country by area. In situ monitoring of the environment cannot meet the demand of the society. For large areas, remote sensing is the only viable technology for environmental monitoring of the entire area. Although satellite observation capabilities as well as remotely sensed data acquired on board of satellites from both within and outside China are widely available, research is rare that targets the entire territory of China for environmental monitoring. In this paper, the process of environmental change has been categorized into changes in driving forces, environmental change, materials transport and transformation, concentration and abundance change, exposure and infection change of human and ecosystems, and impacts. The potential in monitoring changes in these various aspects is assessed. The progress of environmental change monitoring over the entire territory of China is reviewed. It is suggested that at the methodological level, remote sensing should not only be applied to observation and experiments as well as understanding the change mechanism, but also be coupled with environmental simulation and forecasting so as to support environmental policy making. At the application level, remote sensing should be used beyond its traditional application fields to include species diversity, biological invasion, public health, air and water quality monitoring. Finally, at the technical level, systematic research should be devoted to the improvement of operational and automatic use of remotely sensed data.     

Oxygen isotope variation in the water cycle of the Yamzho lake Basin in southern Tibetan Plateau

Given the potential use of stable isotope in the paleoclimate reconstruction from lacustrine records as well as in the local hydrology cycle, it is crucial to understand the processes of stable isotope evolution in catchment in the Tibetan Plateau region. Here we present a detailed study on the water oxygen isotope based on 2 years observation including precipitation, river water and lake water in the Yamzho Lake, south of the Tibetan Plateau. Temporal variation of local precipitation 5180 shows an apparent ＂monsoon cycle＂. In monsoon season, 5180 in waters is lower. In non-monsoon season, δ^18O in precipitation and lake water is higher and higher river δ^18O exists in spring, probably reflecting the effect of land surface evaporation, together with the higher δ^18O values in spring precipitation. It is also found that the surface lake water δ^18O varies seasonally and annually. The lower lake water δ^18O in the late summer is apparently related to the summer monsoon precipitation. The mean δ^18O value of lake water in 2007 is 1.2‰ higher than that in 2004, probably due to the less monsoon precipitation in summer of 2007, as can be confirmed from the precipitation data at the Langkazi meteorological data. It is also found that an obvious shift of vertical lake water δ^18O reflects the fast mixture of lake water. δ^18O values of lake water are over 10‰ higher than those of precipitation and river water in this region due to the evaporation fractionation. The modeled results show that the evaporation process of the lake water is sensitive to relative humidity, and the present lake water δ^18O reflects a relative humidity of 51% in the Yamzho Lake. It shows that the lake will take 30.5 years to reach present lake water δ^18O given a large shift in the input water δ^18O. The modeled results also reveal that surface lake water temperature and inflow δ^18O have slight effect on the isotopic balance process of lake water in the Yamzho Lake.     

Climate and environment reconstruction during the Medieval Warm Period in Lop Nur of Xinjiang,China

We made multi-proxy analysis of ^14C, grain size, microfossils, plant seeds, and geochemical elements on samples from a profile in the central West Lake of Lop Nur. The grain size suggests relatively stable sedimentary environment around the Medieval Warm Period （MWP） with weak storm effect, which is followed by frequent strong storm events. Abundant microfossils and plant seeds in this stage indicate a warm and humid fresh to brackish lake environment. C, N, and stable elements are high in content in the sediments while Rb/Sr, Ba/Sr, and Ti/Sr are in a steady low level. In addition, plenty of red willows lived here prior to about 700 a B.P., indicating a favorable environmental condition. The results indicate that the environment in Lop Nur and its west bank turned to be favorable at about 2200 a B.P., where the Loulan Culture began to thrive. Then the climate and environment came to be in the good condition in the Tang and Song Dynasties, when the storm effect became weaker, rainfall increased and the salty lake water turned to be brackish to fresh lake water. Hence, limnic biomass increased with higher species diversity.     

Preliminary research on Megalake Jilantai-Hetao in the arid areas of China during the Late Quaternary

We identified geomorphological, sedimentary and biological evidence of high lake levels around the current Jilantai Salt Lake through field investigations and through analyses of regional remote sensing images. There are four groups of shorelines at elevations of around 1060, 1050, 1044 and 1035 m a.s.l., being 37, 27, 21 and 12 m above the current salt lake surface, respectively. Littoral deposits of sand and gravels are found at elevations between 1070 and 1080 m a.s.l., 47 to 57 m higher than the current salt lake surface, although palaeoshoreline landforms are only preserved at several sites. At Herimuxini, on the northern margin of the Ulan Buh Desert, typical lacustrine sediments and sand-gravel littoral deposits also occur at elevations of 1080 m a.s.I, and below. A 11-km-long typical spit extends eastward from this shoreline gradually reducing in elevation from 1050 to 1035 m a.s.I. In some sand-gravel quarries along the southern bank of the Yellow River on its Great Bend, such as those located near the Hydrological Gauge Station and Shilazhao Town, shoreline features were identified. Littoral deposits overlying the alluvial-diluvial layers occur in a sand quarry near Balagong in Hangjin County. There are also beachrock and littoral deposits preserved on the cut-and-built terraces at several sites along the southern piedmont of Langshan-Yinshan Mountains. In addition, a profile revealing subaqueous delta sediments was identified near Wuhai, where the Yellow River enters the basin. Typical lake sediments also exist at the Togtoh Platform on the eastern end of the Hetao Plain. Aquatic Mollusk shells are common in the littoral deposits, including several species of Corbicula, Radix lagotis, R. xauricularia and Gyraulus convexiusculus. Ostracode shells can also be identified in finer sediments. Typical ver- tical prograding sequences are evident in outcrops where lacustrine sediments were well preserved. Wave-rolled cobbles and beachrock are very commonly preserved on the top of profiles in the embankments at     

Remote sensing model and dynamic mechanism for seasonal changes of the euphotic depth in the East China Sea

Based on remote sensing data and models, spatial distribution of the monthly euphotic depth in the East China Sea in 1998 has been obtained. The character of the seasonal changes of the euphotic depth is summarized, and the dynamic mechanism of the key influencing factors is analyzed. The results indicate that the controlling factors of the seasonal changes of euphotic depth in the East China Sea are the seasonal changes of temperature, diluted water from the Yangtze River, the ocean currents and the front process of different water masses.     

landscape Changes in Wenchuan—A Mountainous County in Sichuan, China

Based on the collection of land use maps of three repre sentative years (1972, 1986 and 1995) with a scale of 1 = 100 000, which were derived from interpreted aerial photographs and field surveys, landscape pattern were studied in Wenchuan County of Aba Prefecture, northwest of Sichuan Province, China, Six land use categories were classified according to the actuality of the study area and digitized by manual with the assistance of Geographic Information System (GIS). Landscape spatial and temporal changes were analyzed quanti ficationally by a series of structure, shape, pattern indices, which indicated that grassland dominates in number of patch while both grassland and shrub-land dominate in total area of patch over time. During the last 23 years, the fractal dimension of grassland and shrub-land were decreased while the other types were increased. Highest dominance and fragmentation and lowest diversity characterized the landscape of 1972. In 1986, the landscape pattern had the highest diversity and lowest dominance and fragmentation, which is contrary to the pattern in 1972, Slight change of diversity, dominance and fragmentation has been displayed from 1986 to 1995.     

A test of Snowmelt Runoff Model （SRM） for the Gongnaisi River basin in the western Tianshan Mountains, China

The Snowmelt Runoff Model (SRM) is one of a very few models in the world today that requires remote sensing derived snow cover as model input. Owing to its simple data requirements and use of remote sensing to provide snow cover information, SRM is ideal for use in data sparse regions, particularly in remote and inaccessible high mountain watersheds. In order to verify the applicability of SRM in an environment of continental climate, a test of SRM is performed for the Gongnaisi River basin in the western Tianshan Mountains, the results show that two SRM average goodness-of-fit statistics for simulations, Nash-Sutcliff coeffident (R2) and volume difference (Dv), are 0.87 and 0.90%,respectively. As compared with the application results over 80 basins in 25 different countries around the world, SRM performs well in the Gongnaisi River basin. The results also show that SRM can be a validated snowmelt runoff model capable of being applied in the western Tianshan Mountains.On the basis of snowmelt runoff simulation, together with a set of simplified hypothetical climate scenarios, SRM is also used to simulate the effects of climate change on snow cover and the consecutive snowmelt runoff. For a given hypothetical temperature increase of 4℃, the snow coverage and snowmelt season shift towards earlier dates, and the snowmelt runoff, as a result, is changed significantly at the same time. The simulation results show that the snow cover is sensitive to changes of climate, especially to the increase of temperature, the major effect of climate change will be a time shifting of snowmelt runoff to early spring months, resulting in a redistribution of seasonally runoff throughout the whole snowmelt season.