In the Coupled Model Intercomparison Project (CMIP3) there are 22 global climate models (GCM), of which the simulating capability on snow water equivalent (SWE) over China is tested in this paper. Those models having better simulating capability are chosen to predict the snow water equivalent in the coming 40 years over China. The results show that SWE will decrease in the coming 40 years over China for two scenarios (A1B and B1). It is found that there are SWE decreasing zones mainly in Tibetan Plateau, North China Plain,the middle reaches of Yangtze River and the north of Northeast China. Among them, the most significant decreasing zones are the Pamirs and the west of Kunlun Mountains, followed by the Himalayas and the east of Bayan Har Mountains. There is a slight increase of SWE in Inner Mongolia, the south of Yunnan-Guizhou Plateau and some other zones. Additionally, the decreasing rate in Scenarios A1B is greater than that in Scenarios B1. SWE will significantly decrease in 2021-2050 over the Tibetan Plateau. In autumn and winter, with snow cover increasing, SWE has a slight increase, especially from October to December, but in spring and summer, when snow cover disappears, SWE has a decrease.
Snow cover as the result of climatic change and an indicator of climate change plays an extremely important role in the development of local social economy and improving ecological environment. In order to better guide people in reasonable development and utilization of snow water resources, the response of snow cover ablation to climate change in the Kumalak River basin is discussed in this paper by using MODIS snow cover data in 2001-2010, Land Use/Cover Change data of 2005 and daily meteorological data of Aksu Weather Stations during 1954-2010. It is found that air temperature has been rapidly rising after 1997, especially in winter and spring; the ablation laws of the snow cover has a good response to climate change in annual, monthly and other scales; snow coverage show a parabola rule along with temperature, except for the areas of agricultural land where the snow coverage show a linear variation with temperature. The sensitivity level of snow coverage to temperature change is variable, dependent on land surface types. The order of the sensitivity level is forest lands >shrub>grasslands>snow and ice.
Based on the data of the maximum snow depth and the snow days of 7 meteorologicalstations in Altay region from 1961 to 2010 and the snow density from November 2011 to April2012 on the snow characteristics observations station in Kuwei Hydrological Station, Xinjiang, the characteristics of snow cover change were analyzed, the results showed that the maximum snow depth is on a significant increasing trend, and the trend of the maximum snow depth in the western is greater than that of in the eastern. There are differences in the change of snow days because of the spatial distribution. The snow cover days tended to decrease in Fuyun and Qinghe stations, which are located in the eastern Altay region. That of the other 5 stations is on an increasing trend. The average snow cover days in eastern is slightly more than that of in western Altay region. The data of the snow density shows the snow cover process in winter in alpine areas is a hollow densification process; the sublimation may be a process of snow mass losses, which is caused by temperature, wind speed and vapor pressure. There is a closer relationship between the monthly maximum freeze depth and altitude, but not with latitude. When the depth of snow cover is more 20 cm, it haveinsulation for the underlying frozen soil, and if it is more than 40 cm, its effects is stable on frozen ground, but when snow cover depthis exceeding to 70 cmand more, the freezing depth will change again, which may be caused by the ground temperature.
In this paper, the change process and characteristics of Ürümqi Glacier No. 1 during the past 51 years is studied based on the observation of mass balance on the Ürümqi Glacier No. 1 from 1959 to 2009.It is found that the glacier has experienced nine negative mass balance fluctuations and nine positive mass balance fluctuations since 1959,and the ratio of negative balance years to positive balance years is 35:16. The average negative mass balance has reached -450 mm,the average positive one has reached 130 mm,and the average annual balance has reached -267 mm.From 1997 to 2008,the observed mass balance on the Ürümqi Glacier No. 1 WAs negative mass balance for 12 consecutive years.Furthermore, Ürümqi Glacier No. 1 has been in the state of strong negative mass balance in general,with the largest negative mass balance (-999 mm) in history until 2008. From 1959 to 2009,cumulative mass loss of the glacier reached -13 646 mm (2 402.6 ×104 m3). In other words,the thickness of the glacier in 2009 decreased 15.2 m as compared with that in 1959.This continuous long-term mass loses is very severe for a glacier.
With meteorological and hydrological data from 1961 to 2005 in Hunlun Lake wetland, based on water balance equation, taking the yearly cumulative sum of water balance as a factor, the response model about growth and decline of water area and rise and fall of water level in Hulun Lake wetland was developed in respect of meteorological and hydrological factors, The response characteristics about growth and decline of water area and rise and fall of water level were analyzed with the influencing factors, in order to protect, recover and utilize the Hunlun Lake wetland. It is found that: 1) the growth and decline of water area has good response to the interdecadal change of meteorological and hydrological factors in the wetland. Water area and water level in the wetland will decrease 134.5 km2 and 93.44 cm, respectively, if average yearly air temperature increases 1 ℃. They will increase 10.2 km2 and 7.1 cm, respectively, if yearly precipitation increases 10 mm. They will decrease 1.1 km2 and 0.9 cm, respectively, if yearly evaporation increases 10 mm. They will increase 4.8 km2 and 3.3 cm, respectively, if yearly runoff increases 1×108 m3. 2) Yearly average air temperature increase and yearly precipitation decrease have different contribution rates to decline of the wetland. The former is 13.6% and the later is 86.4%. The later is a dominant factor. 3) If human active effect can be ignored, according to a future climatic prediction, for the lower discharge(Scenario B2), it is preliminary assessed that wetland water area will decrease 275.8 km2, 442.8 km2 and 583.6 km2, respectively, and water level will decrease 191.6 cm, 307.6 cm and 405.4 cm respectively, in 2040, 2070 and 2100. Air temperature change will be the leading factor for the wetland growth and decline in future. Looking forward to the future, the wetland will be warmer and dryer, and then shortage of water resources will intensify, and water area shrinking and water level lowering will accelerate.
Global radiation is the income item of radiant energy in the land surface energy exchange, which is of decisive significance to surface radiation budget, land-atmosphere energy exchange and the formation of weather and climate. In this study, global radiations and relative sunshine duration from 22 radiometric stations across the Tibetan Plateau during the past 40 years were used to determine the coefficients of Angstrom-Prescott model. Combined with the data of other 116 meteorological stations across the plateau, global radiations were estimated for the recent 40 years. It is found that there is abundant sunshine over the main plateau with the average sunshine duration up to 3000 hours or more, and with a better utilization prospect. During the past 40 years, the high global radiation zone has appeared in the west of the plateau, and has extended to the northeast and southeast, with a northern branch reaching the Inner Mongolia Plateau. Although decadal change of global radiation over the plateau has been inconsistent with surrounding areas, on the whole, the anomaly values of global radiation during the 1960s and 1970s were positive, indicating that the global radiation increased over the plateau during these period. While during the 1980s and 1990s, the anomaly values were negative, showing a global radiation decreasing period. Volcanic activity was the major cause for these phenomena. Global radiation over the plateau increased with relative sunshine duration and altitude but decreased with latitude. Among the three factors, sunshine duration was a major factor influencing the global radiation, followed by latitude. The greater variation coefficient of the global radiation appeared in the western plateau. On average, the variation coefficient was only 0.031, indicating that the global radiation in the plateau was relatively stable.
The diurnal and monthly variations of land surface radiation fluxes, turbulent heat fluxes and albedo over Nyingchi Prefecture and Wenjiang District are investigated based on the radiation and turbulent flux data measured with radiometer and Eddy Covariance method in 2008. The influence of monsoon on the radiation fluxes, turbulent heat fluxes and albedo are also discussed. It is found that there are distinct diurnal and monthly variations of radiation fluxes and components of surface heat flux over Nyingchi Prefecture and Wenjiang District. During monsoon season, the influence of cloud on the surface radiation flux and turbulent heat flux results in daily circulation irregular. Monsoon has a significant influence on the ratio of net radiation to sensible and latent heat fluxes in Nyingchi Prefecture. The ratio to sensible heat flux is higher than that to latent heat flux in pre-monsoon season (April-May). In monsoon season (June-July) and post-monsoon period (August-September), the ratio to latent heat flux is higher than that to sensible heat flux. However, in Wenjiang District the ratio of net radiation to latent heat flux is the annual maximum, and that to sensible heat fluxes is nearly equal to that to soil heat flux. The annual mean albedo is 0.21 in Nyingchi Prefecture and 0.14 in Wenjiang District. The albedo is 0.20, 0.19 and 0.20 on Nyingchi Prefecture and 0.13, 0.11 and 0.14 on Wenjiang District before monsoon, during monsoon and after monsoon, respectively.
Land potential productivity change in the lower reaches of the Heihe River was analyzed by using the method of limiting factor conversed modification, which took various factors affecting the land potential productivity as correction coefficients, with the support of Visual MODFLOW used for modeling groundwater level and GIS platform used for grid calculation.In the research, driving factors were analyzed in the processes of calculating land potential productivity under different water-diversion schemes.Analytical results show that when water input in Langxinshan is 7.5×108 m3·a-1, the effective coefficient of water, vegetation coverage and land potential productivity will increase, and the ecological environment will improve. Compared with the status quo, the effective coefficient of water will decrease when water input is 2.5×108 m3·a-1 in the lower reaches of the Donghe River, However, the effective coefficient will increase significantly when the water input is 5.0×108 m3·a-1 or 7.5×108 m3·a-1. The analysis of driving factors will be applied in early warning the local desertification trend, establishing evaluation index system, and providing theory basis for the land utilization of the Heihe River basin.
In this paper, the ground temperature change, climate abrupt change, abnormal years and frost characteristics in Sanjiang Plain are studied by using monthly average geothermal observation data at the depths of 40~320 cm from 1981 to 2010. It is found that the yearly average ground temperature at the depths of 40~320 cm in Kiamusze on the Sanjiang Plain is extremely increasing with the rate of 0.496~0. 574 ℃·(10a)-1,therein the maximum increase is at the depth of 80 cm and the minimum increase is at the depth of 320 cm. As for the climate trend rates of the seasonal average ground temperature, the increase in summer is the maximum one, while the average ground temperatures at the depths of 40 cm, 80 cm and 160 cm are higher than those in autumn and winter. But the average ground temperature at the depth of 320 cm increases obviously in summer. The trend rates of ground temperatures at different depths are a little high, mainly owing to the summer precipitation decreasing. However, the spring and winter precipitation increase results in snow cover deeper, which is favorable to ground temperature saving. The ground temperature changing is fastest at the depth of 40 cm in spring, while that at the depth of 160 cm is slowest. The ground temperature increases fastest in summer at the depths of 80 cm and 160 cm; but in autumn, the temperature increases with depth at the same time, and with a maximum at the 320 cm depth; increasing rate of average ground temperature at the depth of 40 cm is the maximum while that at the 160 cm depth is the minimum. There is a wave fluctuation in the average ground temperature variation at the depth of 40~320 cm. The maximum values at the depths of 40 cm and 80 cm appear in August, while that at the depth of 160 cm depth appears in September and that at the depth of 320 cm appears in October; the minimum value appears in February, but that at the depth of 160 cm appears in March and that at the depth of 320 cm appears in May. The phase of the maximum and minimum of average ground temperature lagged behind with depth. The annual range of average ground temperature in the depth of 40 cm is the largest, and decreases with depth. The annual average ground temperature in Kiamusze increased obviously yearly in the 1980s and the 1990s, but it decreased in the 1980s. The seasonal average ground temperature variation was low in the 1980s, especially in summer. There is obvious vertical variation in the ground temperature profile, with heat flux upwards in January and downwards in July; April and October are ground temperature transition periods. There is not abrupt change in ground temperature at the depth of 40 cm and 80 cm in autumn and at the depth of 320 cm in winter. Abrupt change in ground temperature mainly appeared in the late 1980s and the early 1990s, while there was abrupt change in annual average ground temperature at the depth of 80 cm, and the annual average ground temperature at other depths changed abruptly in the period of 1992-1993. Annual average ground temperatures at the depths of 40 cm and 80 cm were unusual low in 1981 but that at the depths of 320 cm was unusual low in the late 1990s, with an unusual high at the depths of the 40 cm and 160 cm in 2004. Ground at the depth of 40 cm begins to freeze in late November to middle December and begins to thaw in April next year. Ground at the depth of 80 cm begins to freeze in middle December to January next year and begins to thaw in late April to early May. The average frozen period at the depth of 80 cm is 18 d shorter than that at the depth of 40 cm. Ground freezing is much faster than ground thawing.
Numerical simulation is an important method of studying river ice problem. However, due to the complex topography conditions of a natural river, those irregular boundaries must be dealt with reasonably for further research. Based on the study status of river ice numerical simulation, body-fitted coordinates are applied for treating the technology of irregular boundaries, which are summarized in the paper. Sliding boundary method combined with potential flow theory formula is applied for two dimension girds generation, and the σ-coordinates transformation is introduced for the three dimensions girds generation. Water surface location is usually determined by elevation function method. To simulate the unsteady river ice flow, the modified dry or wet method can be considered to deal with the moving boundary situation.
The freezing depth (955 m) of Hetaoyu coal mine auxiliary shaft is the deepest one in the world, 25 m more than that of Balby Potassium Salt Shaft No1, UK, (930m in depth). The shaft has met obstacles in the construction process, and has been forced to use freezing construction. Therefore, the design is very difficult. This paper focuses on the characteristics of the shaft freezing scheme, difficulties and problems to be solved, and makes a comparison with Balby Potassium Salt Shaft No.1. Aiming at the engineering difficulties, large diameter (Φ 168 mm) freezing tube is put forward, together with concentric double fluid supply tube and temperature control tube to control freezing wall development to solve the problems in design. Good effects are obtained. It is useful for the similar engineering in the future.
Ice core study is one of the most important means to reconstruct past climate and environmental changes and to provide the basic background for understanding present climate and projection of future situations. The ice coring drill is an essential tool for the palaeoclimatic research in glaciers. The current paper is to present the procedures of development and application for light-weight core drills for ice coring of glaciers in high mountains in China by our research group. The model BZXJ drill has cutting edge over the counterpart developed by others in the world. We have obtained 125 ice cores with a total thickness of 8 095 meters using this drill.
Based on 51 years (from 1961 to 2011) daily temperature (maximum, minimum and average) data from 37 meteorological stations in Qinghai Province, the mainly characteristics about extreme air temperature are analyzed. It is found that extreme air temperatures have obvious rising trend, but extreme cold indices including frost and freeze days, cool days and nights have trend, and the extreme warm indices including summer days, warm nights and warm days have an ascendant trend. The range of the extreme cold indices declining is more than that of the extreme warm indices rising. Spatially, extreme air temperature indices appear consistent increasing (decreasing) trend in the whole province. Wavelet transform shows that the extreme air temperature exhibited several obvious changing periods, such as 3~8 a, 13 a, 17 a and 27 a. There is a tight correlation between annual mean air temperature and extreme air temperature indices in the province. Extreme air temperature indices show a significant discrepancy as climate suddenly warming, when frost and freeze days, cool days and nights are decreasing, but summer days, warm nights and warm days are increasing obviously. At the same time, the relative indices increase to double, which show that the extreme air temperature indices response well to the climate warming.
Based on the meteorological disaster data from 1984 to 2007, the probability of various meteorological disasters in Qinghai Province and their temporal and spatial distributions are analyzed. In the province, the main disasters are hail, flood, snow disaster, drought, thunder and frost, followed by rain, wind, frost, dust storms, tornado, waterlogging, high temperature, heavy fog. Spatially, Hainan and Haidong Prefectures are damaged by meteorological disasters frequently, with serious harm; Yushu and Golog Prefectures are less damaged and loss. Among them, Huangzhong County, Hainan County and Guide County are damaged by meteorological disasters most frequently; Baima County, Jigzhi County and Yushu County are damaged rather slight. Temporally, May and June have infinite variety of meteorological disasters, and from April to September is a peak period of meteorological disasters. It is found that flood, hail, thunder and lightning disasters are increasing, but other disasters are increasing not so obviously.
Qinghai Province is divided into the Eastern Agricultural area, the area around Qinghai Lake, area of Three Rivers Sources and the Qaidam Basin according to geographical location and geomorphic features. Annual and seasonal abrupt changes of mean air temperature and total precipitation are detected based on data of monthly mean air temperature and monthly total precipitation from 1961 to 2008. It is found that 1)temperature: The annual and seasonal temperatures are all increasing; temporally, winter is the most significant change season, followed by autumn, spring and summer are less changing. Spatially, the Qaidam Basin is the earliest abrupt changing area in annual mean air temperature, followed by the Eastern Agricultural area and the area around Qinghai Lake, and the latest one is the area of Three Rivers Sources. The abrupt changing time of seasonal mean air temperature is not the same between the four areas. 2) Precipitation: The changing trend of annual precipitation is not obvious, except for the Qaidam Basin, where annual precipitation is increasing. Seasonal precipitation changing is not obvious in the main in spring, summer and autumn, but obvious in winter (except for the Eastern Agricultural area). In addition, the abrupt changing signal of precipitation is weak than that of air temperature (except for a few area in individual season).
Based on 1961-2010 observed winter daily temperature data in the Qinghai Plateau, the climatic features and the mechanisms of low temperature concentration degree (LTCD), sustaining more than three days, are discussed. It is found that the LTCD and the low temperature concentration period (LTCP) are able to describe the spatial and temporal heterogeneity of the low temperature very well. The low temperature events and LTCD have been decreasing obviously in the last 50 years and the LTCP has appeared mainly ahead of schedule. The chief circulation system and factors affecting the LTCD in different areas of Qinghai Plateau are studied based on REOF and CAST. The mainly affecting system on Qaidam basin is polar vortex and North Atlantic Oscillation, but that on southern pastoral areas is the local climate feedback mechanism. The mainly affecting system on Tanggula area is located on Polar Regions, Ural Mountains and Eastern Okhotsk Sea. The system relating to eastern agricultural areas exhibits "+-+" wave shape, which can be explained by that the eastwards moving cold air is blocked by eastern high pressure, and then piled over the eastern agricultural areas, forming cold air course and leading to a higher LTCD.
The change trend of extreme climate events is analyzed based on the simulation data of continuous climate change under the scenario of IPCC SRES A1B, with a resolution of 25 km. It is found that: the grade of warm-cold is significantly increasing, which is most obvious in summer, and least in winter. The frequency of extreme high temperature event is also increasing, while that of extreme low temperature event is decreasing trend overall. The grade of dry-wet is increasing, but it is not so significant. Seasonally, it is decreasing in winter, and increasing in other three seasons. The frequencies of extreme drying event and the torrential rain are increasing remarkably. Terrain, especially longitude, latitude and altitude have affected apparently the change trend of extreme climatic events.
In the paper, an assessment model of hail disaster in the Qinghai Plateau is built using data of each time hail hazard from 42 weather stations from 1961 to 2010, by means of moving average, standard normalization and linear regression methods. Analyzing the disaster risk levels,the vulnerability of hazard-affected body and the disaster prevention ability, division of hail disaster risk scales in the Qinghai Plateau is made by using ArcGIS9.3. The results show that the highest-risk areas are mainly in the eastern agriculture region, around the Qinghai Lake, the eastern Qaidam Basins and the eastern and middle headwaters of the three main rivers, The Qilian Mountains is a middle-risk area. The lowest risk areas are in the middle and western of the Qaidam Basins. The division basically coincides with the history records of hail disasters, which is useful for prevention and mitigation of hail disasters in the Qinghai Plateau.
In this paper, thresholds are determined for spring wheat in different growth stages and the values of risk assessment of drought disaster are put forward, through analyzing the correlation of soil humidity and precipitation anomaly percentage, based on data from 47 meteorological stations and eight agriculture representative stations and drought disaster investigation. Risk assessment and division for drought disaster are made through establishing fitting equations of disaster frequency in relation to elevation, longitude, latitude and percentage in growth stage. It is found that 1) in vegetative stage, light-drought (frequency of 15%) takes place in the Qilian Mountains, the southwest of Qinghai Lake and a little part of the eastern agricultural region; medium-drought (frequency of more than 10%) takes place in most part of the Qaidam Basin and most part of the eastern agricultural region; and the heavy-drought and extra-heavy-drought (frequency of more than 10.7% and 34%, respectively) take place in the western Qaidam Basin. 2) In the jointing to booting stage, light-drought (frequency of 15.3％~23.3％) takes place in the Qilian Mountains; medium-drought (frequency of 4%~5.7％) takes place easily in the south part of Qinghai Lake and a little part of the eastern agricultural region; heavy-drought (frequency of 8.3％~ 9.6％) takes place in the eastern agricultural region; extra-heavy-drought (frequency of 27％~44.3％) takes place in Qaidam Basin. 3) In the milk to ripeness stage, light-drought, medium-drought and heavy-drought all take place in the eastern agricultural region, of which the frequency is 2.3％~3.3％, 8.7％~13.3％ and 6.0％~9.0％,respectively; extra-heavy-drought (frequency of was 43.3％~51.3％) takes place in Qaidam Basin.
In this paper, using tree ring indices and monthly normalized NDVI and meteorological data in Wulan and Tianjun Counties form 1982 to 2003, the relationships between tree ring indices and grass NDVI in Buha River basin are analyzed on the basis of the relationships between tree ring indices, grass NDVI and climatic factors. It is found that water-heat conditions distinctly affect the tree ring indices and grass NDVI from June to August. Between air temperature and tree ring indices, grass NDVI in the same period there is a significant correlation. However, the effect of precipitation lags behind air temperature. A remarkable correlation exists between the series of tree ring indices and grass NDVI from June to August, especially in August. The significant correlation between tree ring indices and grass NDVI will be in favour of studying the grass dynamic change in the past. A thousand year variations of grass NDVI in August are reconstructed in this paper based on two tree ring series in Wulan and Tianjun counties.
In this paper, the principle and change tendency of summer drought are studied with the data such as surface observations in Qinghai Province (except for Qaidam Basin), 74 circulation features and reseau data at 500 hPa altitude field of Northern Hemisphere. The results indicated that: 1) there were 15 drought events in the summer of Qinghai Province during 1961-2008, with the probability of 31.3% per years. The probability of moderate drought is larger than that of severe drought and extra-severe drought. The probability of drought is larger in eastern agricultural area than that in other areas. 2) In typical summer drought years, anomaly at 500 hPa altitude upon Eurasian mid-high latitude is positive, with weak polar vortex; in non-dry years, over Mongolia to the Tibetan Plateau there is negative anomaly, with stronger polar vortex towards the eastern hemisphere, and an active India-Burma trough. 3) The western Atlantic in summer and Eurasian zonal circulation index weak last autumn in April Western Pacific Partial August the strong side of the Qinghai-Tibet Plateau surface heating field intensity anomalies index prone to drought in summer; Conversely, West Atlantic type in summer, Eurasian zonal circulation index last autumn on the strong side, the West Pacific-type weak in April, August, Qinghai-Tibet Plateau surface heating field intensity anomaly index weaker, less drought in summer. 4) Back substitution of the simulation equation in 1961-2008 indicates that the accuracy is 83.3% (42/48). Severe drought events in 1977, 2000 and 2002 can be seen in the prediction. The prediction result for 2009-2010 is close to the truth, showing the trend prediction being credible.
According to the historical snow cover data from observation stations in Qinghai Province, variation characteristics of precipitation, snow cover and climatic causes of snow disaster in winter and spring of 2012 were investigated using climatic diagnosis method. It is found that Ural Mountain blocking high stayed stably in the later winter to early spring of 2012 and the geopotential height over the Tibetan Plateau was lower. What is more, plateau trough and India-Burma trough kept active, polar cold air continued to move southwards, and the cold and warm air converged on the plateau. Temperature gradient was larger in southern part and northern part of the province, large amount of precipitation and snow cover took place on both sides of strong frontal zone. During this period, snowfall amount and snowfall days exceeded historical extreme value. At the same time, the maximum temperature was lower and the snow cover was deeper and difficult to melt. As a result, infrequent continuous snow cover spanning from winter to spring occurred, causing snow disasters at different levels to Maqin, Gande, Dari and Maduo Counties, respectively. Snow disasters in southern pastoral areas from January to March in 1982, 1993, 1995, 2008 and 2012 all had the same characteristics. Climatic diagnostic analysis of snow cover and circulation factors in plateau pastoral areas from 1961 to 2009 showed that when the negative value of Arctic Oscillation was more, Ural high pressure ridge was stronger and India-Burma trough and plateau trough were deeper, large amount of snowfall would occur in southern pastoral areas of the province, when snowfall might last for a long time, and the snow disaster would be relatively serious. The opposite configuration of circulation factors will make snow disaster in southern pastoral areas of the province lighter.
Using a hydrological model named HYCYMODEL with a module for glacier ablation, the runoff of a debris-covered glacier watershed on the northern slopes of the Himalayas, China, was simulated successfully. The daily mean temperature and daily mean precipitation at the altitude of 5 180 m a. s. l., obtained during the field work period from May to October, 2009, were the input variables. Besides the above, DEM with a resolution of 50 m and the glacier data from the Glacier Inventory of China were also used. The whole watershed was divided into 40 belts every 50 meters using GIS technique, of which temperature and precipitation were extrapolated. Glacier ablation and evaporation at each belt were calculated based on temperature and precipitation. Monthly temperature lapse rate was calculated ranging from 0.63 ℃·(100m)-1 to 0.73 ℃·(100m)-1 with a mean value of 0.70 ℃·(100m)-1. Precipitation observation from May to October in 2009 revealed that below the altitude of 5 180 m precipitation decreased with altitude with a gradient of -7.3 mm·(100m)-1, and above the altitude of 5 180 m precipitation increased with altitude with a gradient of 22 mm·(100m)-1. Sensitivity analysis revealed that variation of runoff as a whole was primarily influenced by air temperature and the effect of precipitation on the runoff variation was limited. Since the evaporation and heating effect of liquid precipitation on the glacier melting were taken account of, the runoff for the whole watershed responding to the changes of temperature and precipitation was nonlinearly.
The Heihe River basin, located in the interior of Northwest China, is one of the well-known arid and water-shortage areas in China. Water resources mainly take the form of glacier-snow resources, surface water resources and groundwater resources. The Qilian Mountains at high altitude is the headwaters, i.e., the runoff production zone. The middle and lower reaches of the river, mainly in plain, is a main irrigation zone for agriculture, i.e., a water consumption zone. The upper reaches of the river have as many as 428 glaciers, covering an area of 420.55 km2, with glacier resources of about 136.7×108m3. There are 29 sub-rivers, large and small, in the upper reaches of the river, with a mean annual runoff of 37.83×108m3·a-1 from the mountain areas. The runoff from mountain areas is relatively stable. However, an increasing trend has been seen in recent 10 years. The middle and lower reaches of the river are located mainly in plain. The plain zone of the river includes four large tectonic basins, where groundwater is mainly recharged by infiltration of river water and irrigation channel water. The mean annual groundwater recharge is about 25.637×108m3·a-1. In recent 45 years, with the sustainable development of industrial and agricultural economy, the change in utilization and allocation of water resources, which is due to the increasing sophistication of developing water conservancy in the zone, in addition to the influence of the climate shifting to dry, the total groundwater recharge has decreased by 13.043×108m3, with a decreasing amplitude of 41.3%, and as a result, spring water resources have decreased 22.3%. There are regular, massive, repetitious conversion processes between groundwater and river water along the river. The water resources conversion system exhibits: groundwater in the mountain zone→surface water in the mountain foot→groundwater in the southern basin→surface (spring) water in the middle basin→groundwater in the northern basin. A correct understanding of the water resources characteristics and conversion is undoubtedly a base of achieving the sustainable development of industrial and agricultural economy in the Heihe River basin and adjacency.
Water is the core of the existence and the development of oasis, so arid oasis stability is closely related with water resources. According to data from 2000 to 2009, comprehensive 10-year average water demand is estimated using the methods of evaporation coefficient and quota for various natural ecosystem and social economic system in oasis of Kaidu-Kongque River basin, and oasis stability is discussed under the water resources constraint conditions. The results indicate that: 1) During the period of 2000 to 2009, the theoretical value of annual average water demand for oasis was about 54.80×108 m3, of which 20.55×108 m3 is in Kaidu River basin, 21.90×108 m3 is in Kongque River basin and 12.35×108 m3 is in Bosten Lake, respectively. Compared with 10-year average water supply, one can see that there is a great imbalance between supply and demand of water. 2) Oasis area supported by water resources is approximately 3 139.66 km2 (excluding Bosten Lake area), there into, the area for irrigated agriculture is about 1 395.41 km2. Oasis area supported by water resources is less than actually developing area (5 248 km2), which means that oasis is in unstable state and that the current oasis area should be properly drawn back. At last, the lowest ecological water level of Bosten Lake is preliminarily discussed, and altitude of 1 045 m is regarded as the lowest water level for the large lake, and that 1046.5 m is regarded as the lowest water level for the small lake.
Based on stable oxygen and hydrogen isotopes (δ18O and δD) of precipitation in the upper reaches of Heihe River and soil water and shallow groundwater of the riparian forest, artificial shrubbery forest and gobi ecosystems in the lower reaches of the river, the replenishment sources of soil water and shallow groundwater of these ecosystems were studied. At the same time, by using the IsoSource software, the plant water sources of these ecosystems in the lower reaches of the river were also investigated according to δ18O values of the root water of the Populous euphratica and the Tamarix ramosissima in the riparian forest ecosystem, the Haloxylon ammodendron in the artificial shrubberies, and the Reaumuria soongorica in the Gobi ecosystem, as well as the δ18O of soil water and groundwater. The results show that soil water and shallow groundwater of the riparian forest and the artificial shrubbery forest are replenished by river water which originates from precipitation in the upper reaches. In addition, there is strong evaporation in the artificial shrubbery forest. Owing to far away from channel of river, soil water of the gobi ecosystem is not affected by river water. In the riparian forest ecosystem, the Populous euphratica takes soil water from 40 cm to 60 cm depths and the groundwater as water resources. Soil water from 40 cm to 80 cm is the main sources of the Tamarix ramosissima. The water sources of artificial Haloxylon ammodendron are come from saturated layers of soil water and shallow groundwater at the depth of 200 cm. In the gobi ecosystem, the Reaumuria soongorica mainly absorbs soil water from 175 cm to 200 cm depth. Therefore, soil water and groundwater are main water sources to maintain survival and growth of the plants in the extremely arid regions in the lower reaches of the river.
Based on the mechanisms of soil erosion, the development and progress of studying soil erosion (water erosion) in the Loess Plateau are introduced with slope scale, gully scale, small watershed scale and watershed scale, respectively. The experiences and insufficiency in soil loss control, as well as water conservation, are summarized, combining with the manage practice and investigation in the Zhifanggou catchment, a small basin of the first branch of the Jinghe River in the southern margin of Pingliang Municipality. A recommendation of "planning", "comprehensive", "quantitative measuring" and "weakened measuring" is put forward for well developing the research in future. These will be of great importance for improving soil conservation quality, improving soil erosion status and for achieving the maximization of soil conservation benefits.
In this paper, the effects of freeze-thaw cycle on the structure of soil bacterial communities in the soils of two ecosystems in the interior of the Tibetan Plateau are studied by the method of 16S rDNA clone libraries. The soil samples were taken from two ecosystems: alpine-cold swamp meadow and alpine sandy grassland in the Beiluhe located in the plateau. It is found that α-, β-, γ-, δ-Proteobacteria, Cidobacteria, Actinobacteria, Bacteroidetes, and Planctomycetes are the common bacterial groups in the soils of the two ecosystems. Among them, Proteobacteria, Acidobacteria and Planctomycetes are the predominant ones. Firmicutes is the one that only exists in the alpine-cold swamp meadow soils, while Verrucomicrobia and Chloroflexi are the two that only exist in the alpine sandy grassland soils. Phylogenetic analysis has revealed the rich diversity of bacteria, which decreases with freeze-thaw cycle. Furthermore, Actinobacteria decreases with freeze-thaw cycle in the two ecosystem soils. However, majority of the bacteria shows different variation in the two ecosystems. It is demonstrated that the effect of freeze-thaw cycles on soil bacterial communities has similarity in the two ecosystem soils, but great discrepancy also shows in some bacterial groups.
Ten soil samples were collected from five boreholes in the northern part of Qinghai-Tibetan Plateau. Actinomycetes isolated using two mediums were identified as Streptomyces spp. according to their morphological characteristics in combination with full 16S rDNA sequencing. It is found from antimicrobial and physiological studies that 24% of the total isolates have antimicrobial activity to the target pathogens. H2S, organic acid, catalase, esteraseⅠ(Tween-20), esteraseⅡ(Tween-40), esteraseⅢ(Tween-80), amylase, proteinase, urease producing strains account for 56%, 28%, 93%, 22%, 67%, 41%, 43%, 61% and 57% of the total isolates, respectively. The abundant physiological diversity and secondary metabolites of streptomycetes isolated from permafrost of the Tibetan Plateau may have some potential perspective of biotechnology and biological products.
In this article, systematic sampling methods are used to analyze the growth condition of Artemisia ordosica cultivated in red sand soil and the sierozem in Lanzhou North-South Hills. It is found that A. ordosica has an extensive adaptability to the barren and non-suitable for afforestation soil in Lanzhou North-South hills: The A. ordosica with three-year growth period is able to cultivate in the red sandy soil. In the horizontal ditch, A. ordosica stalk mainly reaches 5~10 mm, with height of 100-160 cm, average coverage of more than 90%, and density of 17 trees per square meter; In the artificial slope over 60°, A. ordosica stalk mainly reaches 0~5 mm, with height of 80~100 cm, average coverage of 80%, and density of 30 trees per square meter; In the original slope over 60°, A. ordosica stalk mainly reaches 0~5 mm, with height of 20~40 cm, average coverage of 80% , and density of 25 trees per square meter; In the untamped backfill terrace with collapse and slope of 45°, A. ordosica stalk mainly reaches 5~10 mm, with height of 60~80 cm, average coverage of 60%, and density of 43 trees per square meter; The A. ordosica with five-year growth period is able to cultivate in the artificial sierozem slopes of 60°. Its stalk is 4 mm in the uphill and 25 mm in the downhill and mostly in the slope surface reaches 4~9 mm. The A. ordosica height mostly reaches 40~80 cm, with average coverage of 40% and density of 16 trees per square meter in the uphill, but with average coverage of 48% and density of 12 trees per square meter in the downhill. The A. ordosica in the afforestation of Lanzhou North-South Hills has the characteristics that large coverage with big crown and small bulk density, but low coverage with little crown and large bulk density, dependent on soil moisture.
27 samples were collected from a north-south transect in the Small Yourdusi Basin in the Central Tianshan Mountains, Xinjiang Region, in order to reveal the relationship between sporo-pollen and vegetation zones and the sporopollen sources in the Meitiane Lake in the basin. It is found that sporopollen assemblages are mainly constitute of Picea, Compositae, Poaceae, Artemisia, chenopodiaceae, Thalictrum, Cyperaceae, Polypodiaceae and other fern spores. There is a good correspondence between the surface sporo-pollen assemblages and the zones of vegetation. The principal component analysis also demonstrates that the distribution of vegetation is primarily controlled by temperature. The major factors that influence the dispersal of Picea pollen are the uplifting air current and stream. The Picea pollen is carried by the valley winds upwards and southwards from the Picea schrenkiana forest in Kunes River basin to the north of the Meitiane Lake, and then blocked by the hills adjacent to the lake. As a result, Picea pollen deposits on the slopes to the south of the lake, and then runs downwards into the lake by rain water and melt water. Specially, most pollen taxa are in accordant with the distribution of their relevant plant types. Pollen percentages of Artemisia and Chenopodiaceae may represent the mixed signal of regional pollen rain to some extent. It is found that A/C ratio fluctuates when small amounts of Artemisa and Chenopodiaceae are counted, whereas it is relatively stable when a total of more than 280 grains are counted. This is worth to pay attention to as reestablishing palaeoenvironment by A/C ratio.
In this paper, based on the techniques of remote sensing and GIS, the variation of land use in the Manas River basin was analyzed for various ecological and economic sub-areas from 1958 to 2006. Also, the variation characteristics of ecosystem service values were investigated by using of the Costanza evaluation model. It is revealed that the ecosystem service values reduced from ￥22.13 billion RMB Yuan in 1958 to ￥16.05 billion RMB Yuan in 2006; with a net loss of ￥6.08 billion RMB Yuan in the basin. The ecosystem service value coefficient of each land use was close to regional actual value. Thus the research results are credible. Ecosystem services of various ecological and economic sub-areas existed obvious variations in temporal and spatial scales during the period of 1958-2006. Therefore, according to the ecological and economic characteristics and ecological problems in various ecological and economic sub-areas, ecological recovery strategies are proposed, which are vital to achieve sustainable development in the Manas River basin.
