Table of Content

15 July 2013, Volume 30 Issue 4 Previous Issue    Next Issue

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Spatiotemporal Pattern and Process of Inland Lake Change in the Qinghai-Tibetan Plateau during the Period of 1976-2009 LI Jun-Li, SHENG Yong-Wei 2013, 30 (4):  571-581.  Abstract ( 1819 )   PDF (3236KB) ( 1270 )   In this paper, the dynamic variation of the inland lakes in the Qinghai-Tibetan Plateau was investigated based on the mapping of the lakes in 4 years (1976, 1990, 2000 and 2009) and the Landsat time series images so as to reveal the spatiotemporal variation of the lakes in the plateau under climate change in recent decades. The temporal processes and spatial patterns of change of the lakes were analyzed at drainage basin scale, and the mechanism of inland lake change was discussed from the aspects of regional climate factors and recharge water sources of the lakes. The results showed that the inland lakes in the plateau were holistically in a shrinkage during the period of 1976-1990 but in an expansion during the period of 1990-2009, and the total lake area was expanded by 27.3% during the period of 1976-2009. Considering from the spatial patterns of lake change, the lakes recharged by groundwater were in a dramatic expansion or shrinkage, but those recharged by glacial melt water were stable or in a slight expansion. Recharge water sources of the endorheic basins affected strongly the lake change rate, the change of climate factors, such as precipitation, evaporation and air temperature, could be used to explain the shrinkage or expansion of the lakes. Therefore, regional climate change is the key factor causing the dramatic change of the inland lakes in the Qinghai-Tibetan plateau, and the recharge water sources could be regarded as the main factor affecting the regional difference of lake change. References | Related Articles | Metrics

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WEAP based Simulation of Satisfaction Degree of Irrigation Water in the Mainstream Area of the Tarim River Basin XU Hui, ZHANG Yun-Chao 2013, 30 (4):  582-587.  Abstract ( 1825 )   PDF (1027KB) ( 1128 )   Rational redistribution and utilization of water resources for farming irrigation and natural ecology in the mainstream area of the Tarim River Basin is critical to the ecology and environment improvement. The monthly satisfaction degrees of irrigation water of all the irrigated areas were simulated with the Water Evaluation and Planning System (WEAP) model based on the assigned water volume from the “Shortterm Comprehensive Improvement Plan of the Tarim River Basin” and the premise of the minimum ecological water demand. The water demand of natural vegetation was estimated through the quota method and the minimum water demand of the mainstream at 90% reliability rate of stream flow. The volumes of available water resources were computed by subtracting the ecological water demand and water loss along the river channel from the assigned quota, and they were 1.217×109 m3, 7.45×108 m3 and 5.69×108 m3 under the stream flow reliability rates of 50%, 75% and 95%, respectively. The WEAP model was developed for estimating the satisfaction degrees of irrigation water in the mainstream area of the Tarim River Basin by inputting the modeling factors and data, such as the rivers, river channels, reservoirs, irrigated areas, water supply priority, monthly volume of available water resources, crops, irrigation programs of all the irrigated areas and water loss of the reservoirs. The satisfaction degrees of irrigation water in all the irrigated areas were simulated. Satisfaction degree of irrigation water in the areas irrigated by both rivers and reservoirs was higher than that in the areas irrigated by rivers only. Shortage of irrigation was the most serious in November and March, and then in April and May in the mainstream area of the Tarim River Basin. References | Related Articles | Metrics

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Change of Glaciers in the Central Qilian Mountain CHEN Hui, LI Zhong-Qin, WANG Pu-Yu, ZHOU Ping, JIN Shuang 2013, 30 (4):  588-593.  Abstract ( 1425 )   PDF (1366KB) ( 1314 )   Change of glaciers in the central Qilian Mountain in recent 50 years, including the Heihe River Basin and the Beidahe River Basin, was analyzed based on the remote sensing data and field survey. Results indicated that the total area of 910 glaciers investigated was reduced by 21.7% with a reduction rate of 0.002 km2•a-1 during the period from 1956 to 2003, in which the total area of glaciers was reduced by 29.6% in the Heihe River Basin and 18.7% in the Beidahe River Basin. Reduction rate of the small glaciers was generally higher than that of the large ones, indicating that the small glaciers were more sensitive to climate change than the large ones. There was a regional difference in area change of glaciers due to the different geographical locations of the glaciers, local climate conditions and topographic factors in the central Qilian Mountain. Recent field survey revealed that the total area of glaciers in the Hulugou River Basin located in upper reaches of the Heihe River was reduced by 30.1% during the period from 1956 to 2010, and the reduction of glacier area in recent 7 years was 5 times of that in previous years. Shiyi Glacier located in this region was separated into two independent glaciers due to the serious ablation. Glacier melt runoff is the vital water source and plays an important role in stabilizing stream flow and regulating annual variation and distribution. References | Related Articles | Metrics

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Change Trend of Groundwater Depth in Linze County in Middle Reaches of the Heihe River Basin in Recent 30 Years WANG Jin-Feng, CHANG Xue-Xiang 2013, 30 (4):  594-602.  Abstract ( 1628 )   PDF (2936KB) ( 1245 )   In this study, the semivariant function analysis, model selection and spatial interpolation analysis on groundwater depth in the years of 1986, 1991, 1996, 2001, 2006 and 2010 were carried out based on the monitoring data of groundwater depth in Linze County in middle reaches of the Heihe River Basin during the period of 1984-2010, GS+, ArcGIS and geostatistics. The results showed that the groundwater depth in all the irrigated areas in Linze County was holistically in a drawdown under the effects of topographic conditions and land use change. Monthly fluctuation of groundwater depth was very low in the Gobi deserts and riparian wetlands, its curve was bimodal in oasis cropland ecosystem, oasis marginal zone and oasisdesert ecotone, and the two peaks occurred in May and December. The theoretical model of groundwater depth is an exponential model. Spatial change of groundwater depth was mainly caused by the structural factors, such as climate change, terrain and geology conditions. There was no significant regional difference of groundwater depth change. Groundwater depth was deep in the south and north areas but shallow in the central area. Area of the regions where groundwater depth was shallower than 4 m  was reduced by 337.01 km2 and accounted for 12.58% of the total area in the county; however, the proportion of area of the regions where groundwater depth was deeper than 6 m was expanded by 66.7%. References | Related Articles | Metrics

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Affecting Factors of Bioremediation in Improving Soil Contaminated by Thickened Oil DONG Ya-Ming, LIU Qi-You, ZHAO Dong-Feng, ZHAO Chao-Cheng, GAO Bo 2013, 30 (4):  603-608.  Abstract ( 1487 )   PDF (2382KB) ( 1312 )   Thickened oil causes inevitably the serious contamination of edatope and impacts human health and environment in its mining, storage, transportation, refining and using process. It is necessary to take effective measures for improving soil contaminated by thickened oil. The microbial screened consortium KL9-1 was used to research the bioremediation for improving soil contaminated by thickened oil, and the factors in the biodegradation progress were studied. The results showed that the pH value, inoculum size, soil N/P, surfactant dosage, tillage frequency, watering frequency and raising agent affected significantly the bioremediation. In the soil contaminated by thickened oil per kilogram, the initial conditions of pH of 8.0, inoculum of 70.0 mL, N/P of 3∶[1 and surfactant dosage of 4.0 g were controlled, the soil was watered every two days and plowed every four days, rice husks were used as a raising agent, and the petroleum hydrocarbon degradation rate could be as high as 54.07% after carrying out a biodegradation for 70 days. References | Related Articles | Metrics

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Soil Moisture Content under Stubble Retention After Dry framing Winter Wheat Harvest Based on APSIM Model YANG Xuan, TAN Guang-Yang, SHEN Yu-Ying 2013, 30 (4):  609-614.  Abstract ( 1450 )   PDF (1580KB) ( 903 )   APSIM (Agricultural Production Systems Simulator) is a modeling framework which is enabled to simulate broad spectra of biophysical processes in farming system and is capable to predict a variety of scenarios. APSIM is also sensitive to climate change and different water conditions in dryfarming area. In order to examine the application of APSIM model in dryfarming area in the Loess Plateau, the values of soil moisture loss after winter wheat harvest were measured under different stubble retention treatments, and APSIM was used to predict the output. The results indicated that soil moisture evaporation under stubble retention (S) was 16.7%-23.9% lower than that under fallow (F), stubble mulching with tillage (TS) and tillage (T) treatment after a rainfall event. Simulation of APSIM model could be used to explain 71%-92% change of soil moisture content. Under a simulated rainfall with a rainfall intensity of 66 mm•h-1, soil moisture evaporation was decreased by 27.8% under SS treatment (with stubble of 2 t•hm-2) and 49.4% under LS treatment (with stubble of 4 t•hm-2) compared with that under F treatment. APSIM model could be used to predict 96%-99% soil moisture loss. The results demonstrated that APSIM was satisfactory to predict the process of soil moisture loss through evaporation in dryfarming region. References | Related Articles | Metrics

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Variation of Fractal Dimension of Soil Particle Size Distribution in the Aral Reclamation Area in Oasis Development DU Hai-Yan, ZHOU Zhi-Bin, LIU Feng-Shan, YAN Bing 2013, 30 (4):  615-622.  Abstract ( 1739 )   PDF (2021KB) ( 1060 )   The study area, Aral Reclamation Area, is located in the northern marginal zone of the Tarim Bain, Xinjiang, China. In this paper, the variation of fractal dimension of soil particle size distribution (PSD) was researched, and the relationships between the fractal dimension of soil particles and the volume percentage of PSD and its affecting factors were analyzed using the singlefractal calculation method and the PSD data obtained with laser diffraction technique at different soil depths under different land use types. The study results will help us to characterize the change of soil physical environment in the transform of different land use types in oasis development, and even provide the suggestions for the rational utilization of different soils. The study results revealed that the soil in the Aral Reclamation Area was dominated by sandy loam, and the soil fractal dimension value varied in a range of 1.883-2.405. There was a significant negative correlation between the soil fractal dimension value and the volume percentage of soil particles within 0.05-0.25 mm and 0.25-1 mm, but a significant positive one between the soil fractal dimension value and the volume percentage of soil particles < 0.05 mm. The grain size of 0.05 mm was the critical value for deciding the relationship between the soil particle fractal dimension and the volume percentage of soil PSD. The grain size of soil particles was mainly in a range of 0.01-0.05 mm in hinterland of the oasis, but a range of 0.05-0.25 mm in the marginal zone of the desert. The volume percentage of fine soil particles was increased, that of coarse ones was decreased, and the fractal dimension of soil particles was in a gradual increase trend. References | Related Articles | Metrics

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Soil Water and Salt Migration in Cotton Field under Soil FreezingThawing Temperature JIN Zhi-Feng, HU Dan-`Tu-Ma-尔Bai, MOU Hong-Chen, MA He-Mu-Jiang, LI Wen-Juan 2013, 30 (4):  623-627.  Abstract ( 1671 )   PDF (2034KB) ( 1110 )   This paper researched the effect of temperature on soil water and salt migration in cotton field during freezing thawing periods under drip irrigation in north Xinjiang, China. The results showed that the effect of air temperature on soil temperature was continuously decreased with the increase of soil depth, the lag time was ceaselessly lengthened, and the soil thawing rate was much higher than soil freezing speed. The soil thawing rate in topsoil was higher than that in subsoil. Soil moisture content was strongly affected by temperature. During freezing period, soil water migrated slowly from nonfrozen layer to frozen layer, and it migrated from subsoil to topsoil under the effect of evaporation during thawing period. Analyzed result showed that temperature affected indirectly the soil salt migration. During freezing period, soil water migrated slowly, and the change of soil salt migration was low; during thawing period, soil water migrated actively, and the change of soil salt migration was high. Under rapid temperature increase, soil water migrated continuously. Sustainable cotton cropping was seriously affected due to the upward migration of soil water in soil layer of 120-150 cm under drip irrigation. References | Related Articles | Metrics

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Application of EM38 in Soil Salinity Zonality XIA Ying-Hui, XIONG Hei-Gang 2013, 30 (4):  628-633.  Abstract ( 1252 )   PDF (1214KB) ( 987 )   In this paper, the relationship between the EM38 earth conductivity measurement and soil (1:5) conductivity solution was analyzed, and the prediction models were developed by taking soil solution conductivity as a dependent variable and earth conductivity as an independent variable. In order to ensure the credibility of the models, the credibility of EM data was analyzed. Through correlation analysis between EMh and EMv, the results revealed that the standard mode was consistent with the EM measurement in vertical mode and was capable of reflecting soil salt content, so the data were applicable. An ideal prediction model should be selected in predicting soil salt content. The values of EM38 measurement of earth conductivity could be used to predict soil salt content and analyze the spatial variation of soil salinity. Results showed that the spatial variation of soil salinity in the study area was the salt accumulation in topsoil and zonal. Results showed that the angle of salt zone between the shallow soil layer (0-30 cm) and the moderate (30-60 cm), deep (60-90 cm) and bottom (90-120 cm) soil layers was larger than 5°, but within 3° between it and other soil layers. Especially, the zonal trend of soil salt content in shallow soil layer was consistent with that of vegetation and fitted the change features of landforms in the study area. References | Related Articles | Metrics

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Distribution Patterns of Main Populations of Ammodendron argenteum Communities in the Takeermohuer Desert LI Jin, HUANG Li-Ping, 吕Hai-Ying , WANG Xiao-An 2013, 30 (4):  634-639.  Abstract ( 1678 )   PDF (721KB) ( 903 )   In this paper, it is attempted to probe into the patterns of main populations of Ammodendron argenteum communities and their affecting factors in Takeermohuer Desert based upon the data collected through field work in sample plots. The dispersal index, clump intensity, mean crowding, patch index, Green index, intensity index, fitting test of Poisson distribution and negative binomial distribution were used in the study. The distribution patterns and affecting factors of the main populations of A. argenteum communities were researched, and the relations among the six indexes were analyzed with correlation analysis. The results revealed that the distribution patterns of the main populations of A. argenteum communities were all clumped, and there was a difference in clump intensity. Moreover, the distribution patterns were closely related to the biological habits of the main populations diffused and bred by seeds, also to the spatial asynchronization of the main populations of the community ecology induced by spatial asymmetry of nutrient and soil moisture content in the severe desert, and the common ecological habits of the populations adapted for the desert environment. A certain ecological significance was characterized by the six exponential methods, and a mutual corroboration of the x2  test for Poisson distribution and negative binomial distribution was carried out so as to determine the spatial distribution patterns of the main populations of A. argenteum communities well. References | Related Articles | Metrics

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Growth of Leaves of Main Landscaping Tree Species in Northwest Liaoning Province WANG Kai, WANG Dao-Han, WEI Jun, ZOU De-Jun, LU Hui 2013, 30 (4):  640-645.  Abstract ( 1260 )   PDF (1364KB) ( 936 )   In this paper, the specific leaf area and allometry of the main landscaping tree species in northwest Liaoning Province were estimated using the standardized major axis estimation and cluster analysis. The results showed that the common slope between leaf area and biomass of the tree species was 1.052. Among all 55 tree species, the slope of 46 tree species was less than 1.0, of 1 equaled to 1.0, and of 8 was large than 1.0. The common slope between leaf water content and biomass was 1.052, in all the 55 tree species, the slope of 42 tree species was less than 1.0, and of 13 was larger than 1.0. Specific leaf area ranged from 48.83 to 276.52 cm2•g-1. The tree species could be divided into 3 groups when the euclidean distance was 15. These results indicated that there were the isometric relationships among leaf biomass and leaf area and water content in all the 55 tree species in northwest Liaoning Province. However, allometry index was different among the tree species. Specific leaf area of the tree species in northwest Liaoning Province was low since the tree species adapted the severe environment. It was suggested to select the tree species with low specific leaf area as the landscaping tree species in arid and semiarid area. References | Related Articles | Metrics

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Root Activity of Transplanted Pinus tabulaeformis Seedlings under the Interaction of Three Factors BAI Jin-Hua, WANG Tun, GUO Jin-Ping, XU Yan-Ping, GUO Hong-Yan 2013, 30 (4):  646-651.  Abstract ( 1531 )   PDF (1291KB) ( 1093 )   Four year old transplanted Pinus tabulaeformis seedlings were grown in pots under the treatment of three different levels of natural light intensity, soil moisture content and seedling water content. The root activity of transplanted P. tabulaeformis seedlings under the interaction of three factors was studied. The results showed that the root activity of transplanted P. tabulaeformis seedlings was reduced gradually with the decrease of natural light intensity and seedling water content and the increase of soil moisture content. The root activity of transplanted P. tabulaeformis  seedlings under natural light was significantly higher than that under shadow when seedling water content was 63% or soil moisture content was 30%; when the transplanted seedlings were under one of the conditions of natural light, 63% seedling water content or 30% soil moisture content, the root activity of transplanted seedlings was significantly changed with the change of other two factors; when the transplanted seedlings were under the natural light intensity and 53% natural light intensity, or 30% and 50% soil moisture content, the root activity was reduced with the seedling water loss. References | Related Articles | Metrics

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Growth Model and Process of Populus nigra var.thevestina in the Junggar Basin SHI Xiang, TANG Cui-Ping, ZHOU Fang-Long 2013, 30 (4):  652-658.  Abstract ( 1404 )   PDF (1466KB) ( 971 )   Research on dynamic process of the growth of tree height, diameter at breast height (DBH) and timber volume of poplar plantation is of great significance in the further understanding of growth laws and establishing the corresponding foster and management measures. The whole growth process of 19 a-old Populus nigra var. thevestina plantation in the Junggar Basin, including the growth of tree height, DBH and timber volume, was studied using the trunk analysis method, and five models related to the growth of tree height, DBH and timber volume, including the power function type, quadratic and cubic polynomial regression model, Logistic model and Richards model, were developed and compared. The results showed that the rapid growth of tree height occurred at the 3-14 a-old trees, that of DBH at the 2-19 a-old ones, and that of timber volume at the 2-18 a-old ones. The rapid growth duration of tree height occurred later than that of DBH and timber volume, and timber volume grew rapidly at the early stage. The maturity age for the highest timber volume of P. nigra varied in a range of 27-30 a. The statistical significance of five models used to describe the growth of tree height, DBH and timber volume were all lower than 0.01, which means that all the five models were fitted well. Richards model was the optimal one to describe the growth process of tree height, DBH and timber volume of P. nigra, and their correlation coefficients were as high as 0.983, 0.999 and 0.998 respectively. References | Related Articles | Metrics

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Sand Trapping Capability of Two Dominant Plant Species in the Qira Oasis desert Ecotone HAN Zhang-Yong, WANG Xue-Qin, YANG Fan, MA Yang 2013, 30 (4):  659-665.  Abstract ( 1422 )   PDF (2011KB) ( 924 )   In the Qira oasis desert ecotone at the southern marginal zone of the Taklimakan Desert, the sand trapping capability of two dominant plant species (Alhagi sparsifolia and Karelinia caspia) was studied by analyzing the morphological parameters of these two plant species and their nebkhas. The results showed that the mean aboveground plant height of the two species and the height of their nebkhas was similar, and the mean plant crown area and volume of A. sparsifolia was nearly 1.8 times larger than those of K. caspia. The mean basal area and volume of A. sparsifolia nebkhas was nearly 1.7 and 2.0 times of those of K. caspia nebkhas, respectively. The correlation among the morphological parameters of A. sparsifolia nebkhas was higher than that of K. caspia nebkhas, and the increase of basal area and volume of A. sparsifolia nebkhas was higher than that of the K. caspia nebkhas. Generally, A. sparsifolia has a stronger capability of taking space than K. caspia, and also a stronger capability of trapping aeolian sand. However, a weaker capability was shown in its early stage of growth. The two species show differences in sand trapping capability at different growth stages. References | Related Articles | Metrics

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Soil Seed Bank under Natural Forest of Prunus divaricata in Xinjiang, China LIU Ying, ZHAO Yu, YAN Jun-Jie, LI Hai-Bing, CONG Gui-Zhi 2013, 30 (4):  666-673.  Abstract ( 1832 )   PDF (1436KB) ( 793 )   Field survey and laboratory observation and experiment were conducted to study the characteristics of soil seed bank under natural forest of Prunus divaricata in Huocheng County, Xinjiang, China, and also the composition and vertical distribution of soil seed bank under litter layer, life form of vegetative, biodiversity and similarity between aboveground vegetation soil seed bank. The results were as follows: (1) Fortyeight species in 19 families were identified from the soil seed bank through germination test in laboratory. In the species of soil seed bank, 20 species were therophytes, they were dominant and occupied 41.7% of the total species in soil seed bank, and 15 species were geophytes and accounted for 31.3% of the total; (2) Density of seeds in soil seed bank was increased at first, and then decreased rapidly with the increase of soil depth, more than 90% seeds were in litter layer and soil horizon of 0-5 cm in depth, and about 90% seeds of P. divaricata were in litter layer and soil horizon of 0-2 cm in depth; (3) The species diversity in different layers of soil seed bank was that the Margalef index and ShannonWiener index of species were the highest in herb layer, they were decreased in arbor and shrub layers, and the species diversity was mainly affected by species richness in herb layer; (4) Sorensen similarity coefficient between the vegetation and soil seed bank was 0.315, which revealed that the contribution of aboveground vegetation to soil seed bank was high. The conclusions above revealed that the biodiversity and its vertical distribution were strongly affected by grazing disturbance. References | Related Articles | Metrics

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Darkling Beetles Diversity in Southern Marginal Zone of the Gurbantonggut Desert XU Yang-Cheng, LOU Qiao-Zhe, MA Ji-Hong, 吕Zhao-Zhi 2013, 30 (4):  674-680.  Abstract ( 1506 )   PDF (1550KB) ( 1177 )   In this paper, the diversity of darkling beetle community in the marginal zone of the Gurbantonggut Desert was studied after investigating the spatial distribution of darkling beetles in the study area. Six hundred trappers were set to catch darkling beetles in the desert during the period from May to July 2010. The result were as follows: (1) The dominant beetle species were in a clear trend to select microhabitats; (2) The biodiversity of darkling beetles was low at landscape scale, and the engenvalues (including the activity density, species richness, biodiversity index and dominance index) of darkling beetles were quite different from different landscapes: (3) The interference of nig agricultural projects caused the low species richness and low evenness index. But the difference of which was not significant. The decrease of diversity index and the increase of dominance index reached to a significant level (P<0.05). The activity density of Library[JP8]’s[JP] east turtle beetle and smooth fat desert beetle increased, but that of the others decreased. Darkling beetles have a significance of indicating the fragile desert habitats. References | Related Articles | Metrics

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Conflicts between Canis lupus and Community Nomads in the Mt. Kalamaili Ungulate Nature Reserve, Xinjiang, China LIU Shu, CHU Hong-Jun, HAN Li-Li, TAO Yong-Shan, GE Yan, MA Jian-Wei 2013, 30 (4):  681-688.  Abstract ( 2312 )   PDF (1003KB) ( 1047 )   In recent 5 years, wolves (Canis lupus) preyed on livestock frequently and caused huge economic losses to the local community nomads, and more and more sharp conflicts between wolves and the nomads occurred. In order to investigate the current situation of wolves and the conflicts between wolves and local community nomads in the Mt. Kalamaili Ungulate Nature Reserve, the face-to-face interview investigation was used to survey the questions mentioned above from July to August 2012. The results were as follows: (1) The community nomads in 6 townships thought generally that there were wolves around the winter nomad settlements or valley settlements, but the number of wolves was obviously different from different regions; (2) In the Mt. Kalamaili Ungulate Nature Reserve, sheep, cattle, camels, goats and horses were the main livestock species preyed on by wolves, especially sheep, and there was an extremely positive correlation between the number of livestock killed by wolves and the owned livestock number of the families; (3) Wolf predation to livestock occurred mainly in winter pastures at night; (4) Wolves preyed on livestock close to the nomad settlements and water sources far away from the roads, mining areas and tourist spots where human activities were frequent; (5) About 60.5% nomads thought that wolves were harmful to prairie ecosystem. References | Related Articles | Metrics

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Spatiotemporal Evolution of Effective Accumulated Temperature ≥10 ℃ in China in Recent 50 Years LIU Shao-Hua, YAN Deng-Hua, WENG Bai-Sha, XING Zi-Qiang, WANG Gang 2013, 30 (4):  689-696.  Abstract ( 2082 )   PDF (2078KB) ( 2059 )   The effective accumulated temperature ≥10 ℃ is an important index to measure the heat resources in a zone. So the distribution of effective accumulated temperature ≥10 ℃ affects strongly the distribution of agriculture and ecological pattern. In this study, the values of effective accumulated temperature ≥10 ℃, first day and duration of temperature above 10 ℃ were calculated using the daily data observed by 583 meteorological stations in China during the period from 1961 to 2010. The spatiotemporal evolution of these factors was studied by the inverse distance interpolation and MannKendall trend test on the technical platform of ArcGIS. The result showed there was a significant spatiotemporal change of distribution of effective accumulated temperature ≥10 ℃ in China after 1985. The effective accumulated temperature ≥10 ℃ was in an increase trend with an increased rate of 0-10 ℃•d (10a)-1, and its isoline center o shifted northward. Area of the regions where the effective accumulated temperature ≥10 ℃ was below 3 400 ℃•d was in a significant reduction. While the area of the regions where the effective accumulated temperature ≥10 ℃ was over 3 400 ℃•d was enlarged with a rate larger than 2.0×104 km2 per year. The area of the regions where the first day of temperature ≥10 ℃ became earlier and the duration of which was significantly prolonged was enlarged. References | Related Articles | Metrics

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Flood Disasters in the Baoji Region during the Period of A.D. 600-2000 WAN Hong-Lian, ZHOU Qi, FAN Wei-Han, LIU Xi 2013, 30 (4):  697-704.  Abstract ( 1968 )   PDF (1965KB) ( 1006 )   Through collecting and analyzing the historical data, the variation stages, trends, grades and causes of flood disasters in the Baoji region during the period of A.D. 600-2000 were researched. The results showed that flood disasters in the Baoji region may be divided into 4 grades, [WTBX]i.e[WTBZ]. the slight, moderate, serious and extremely serious grades, in which the moderate and serious flood disasters were dominant, and their proportion was 71.55% of the total. Extremely serious flood disasters occurred seldom, and their proportion was 8.94% only. In the past 1 400  years, flood disasters occurred seldom in the 10th, 11th, 12th, 13th, 14th and 15th centuries but frequently in 7th, 8th 9th, 16th, 17th, 18th, 19th 20th centuries. There was a spatial difference in occurring frequency of flood disasters, and the frequency was in an order of Baoji > Fufeng > Qianyang > Fengxiang > Feng County > Long County > Linyou > Qishan > Mei County. The difference of occurring frequency of flood disasters between the highest and lowest values was 26 times. Seasonally, flood disasters occurred mainly in summer and autumn. Flood disasters were jointly affected by the geographical location, precipitation, climatic anomaly undulation and human activities. References | Related Articles | Metrics

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Spatiotemporal Evolution of Drought and Flood in the Loess Plateau under Climate Drying warming HU Na-Na, YAN Jun-Ping, LI Shuang-Shuang, LI Min-Min 2013, 30 (4):  705-711.  Abstract ( 1548 )   PDF (2191KB) ( 858 )   In this paper, the spatiotemporal evolutions of annual precipitation, drought and flood were researched using the Kriging interpolation, Mann-Kendall test and Morlet wavelet analysis based on the annual precipitation data observed by 58 meteorological stations in the Loess Plateau during the period from 1960 to 2010 and the background of climate change and peculiar geographic location in China. The results revealed that the annual temperature in the Loess Plateau was increased, but the annual precipitation was decreased in the whole area and the semiarid and semihumid regions. Precipitation variation was the highest in arid zone but the lowest in semihumid regions. There was a regional difference of annual precipitation, the annual precipitation was gradually decreased from the southeast to the northwest, and drought trend became more obvious. The sharp change of mean annual temperature and precipitation occurred in 1996 and 1990 respectively. The drought and flood levels were in an increase trend, especially in the semihumid regions. Occurring frequencies of drought and flood were the highest in arid zone. Drought occurred more easily than flood, and the centers with high drought occurring frequency were dispersed; the occurring frequency of flood was the lowest in the west but the highest in the central area. There were the fluctuation periodicities of drought and flood in the Loess Plateau, the 25-30year fluctuation was the strongest, and it was considered that the current flood period would be ended, but a new drought period would begin. References | Related Articles | Metrics

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Precipitation in the Eastern Part of Northwest China in Recent 50 Years WANG Hui, LONG Xiao, MA Xu-Lin, LIU Yan-Fei 2013, 30 (4):  712-718.  Abstract ( 1605 )   PDF (3636KB) ( 1226 )   Based on the precipitation data observed by 54 meteorological stations in the eastern part of northwest China during the period of 1960-2009, the variation of precipitation in this region was analyzed using the Mann-Kendall test and wavelet analysis. The main results were as follows: (1) Precipitation in the study area was in a slight decrease trend, the precipitation reduction was more obvious after 1990, and the variation of precipitation in area Ⅱwas more significant than that in area I; (2) The precipitation frequency in the study area was dominated by weak and moderate precipitation events, which accounted about 70% of the total precipitation days, and the decrease of weak precipitation frequency was obvious; (3) The proportion of moderate and heavy precipitation accounted for more than 75% of annual precipitation. Decrease of annual precipitation was mainly caused by the decrease of moderate precipitation; (4) The results of wavelet analysis revealed that there were the 3year and 5year fluctuation periodicities of annual, moderate and heavy precipitation, the periodicities of moderate and heavy precipitation in area I were completely different from those in area Ⅱafter the 1970s, and the decrease of moderate precipitation was closely related to the variation of moderate precipitation in the 1970s. References | Related Articles | Metrics

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August Drought in the Three-river Headwaters Region  Based on TRMM Data WANG Zhe, AN Ru, LIANG Xin, QU Chun-Mei, JIANG Dan-Ping 2013, 30 (4):  719-727.  Abstract ( 1227 )   PDF (3545KB) ( 1133 )   Drought is one of the most common natural disasters. Researches on the change pattern of extent and severity of drought have a positive significance to the studies on drought prevention and ecological change. The study area for this research is the “Three-river Headwaters” region in China. Tropical Rainfall Measuring Mission (TRMM) remote sensing data during the period from the year 1998 to 2010 and meteorological raingauge data were used to calculate and analyze the values of standardized precipitation index (SPI) for the study area. The time series of 10-year drought conditions and the spatiotemporal change of drought were analyzed. High accuracy was achieved by integrating the TRMM data with SPI, which was demonstrated that this method was of practical significance for the study area. Related Articles | Metrics

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Applicability of Typical Drought Indexes in the Luanhe River Basin MA Hai-Jiao, YAN Deng-Hua, WENG Bai-Sha, FANG Hong-Yang, SHI Xiao-Liang 2013, 30 (4):  728-734.  Abstract ( 1904 )   PDF (1571KB) ( 1653 )   Based on the monthly precipitation data from 9 meteorological stations during the period of 1957-2010 and the monthly runoff volume data from 5 main hydrometric stations in the Luanhe River Basin during the period of 1956-2000, in this paper drought in the Luanhe River Basin was discussed, and the results were compared using the precipitation anomaly percentage, standardized precipitation index, precipitation Z index and runoff volume anomaly percentage. The results showed that the drought degree explained with the precipitation anomaly percentage was slighter. Compared with the precipitation Z index, SPI could be used to objectively reflect the drought degree in the drainage basin, and it was more ideal in reflecting the drought degree than the precipitation Z index and precipitation anomaly percentage based on the applicability evaluation results of three meteorological drought indexes. Evaluation results of runoff volume anomaly percentage were consistent with the actual situation and suitable for drought evaluation in the Luanhe River Basin. However, there was a lack of integrity and mechanism of these four drought indexes, and it was necessary to comprehensively consider the factors including precipitation, temperature, evaporation and runoff volume so as to put forward a drought index reflecting the inherent mechanism of drought in the drainage basin. References | Related Articles | Metrics

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Changes of the First Frost Dates, Last Frost Dates and Duration of Frost-free Season in Xinjiang during the Period of 1960-2011 PAN Shu-Kun, ZHANG Ming-Jun, WANG Bao-Long, MA Xue-Ning 2013, 30 (4):  735-742.  Abstract ( 2256 )   PDF (5158KB) ( 1123 )   In this paper, the first frost date, last frost date and duration of frostfree season as well as their change trends were analyzed using the linear trend estimation, anomaly analysis and fiveyear moving average based on the daily minimum temperature data observed by 51 meteorological stations in Xinjiang during the period from 1960 to 2011. The results showed that the average first frost date was postponed by 11 days, the average last frost date was moved up by 7 days, and the duration of frostfree season was extended by 17 days. The first frost dates, last frost dates and durations of frostfree season in north Xinjiang, south Xinjiang and the Tianshan Mountains were consistent with those in whole Xinjiang, but the change extent was not different. Their variation was the most significant in the Tianshan Mountains, and then in north Xinjiang and south Xinjiang. The first frost date, last frost date and duration of frostfree season were closely related to the geographical and temperature factors. The first frost date occurred earlier, the last frost date later, and the duration of frostfree season became shorter along with the increase of latitude and altitude. Along with the temperature increasing, however, the first frost date became later, the last frost date earlier, and the duration of frostfree season longer. The effect of minimum temperature was higher than that of average temperature and maximum temperature. References | Related Articles | Metrics

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Response of Runoff Volume to Climate Change in the Kaidu River Basin in Recent 30 Years WANG Wei-Xia, WANG Xiu-Jun, JIANG Feng-Qing, PENG Dong-Mei 2013, 30 (4):  743-748.  Abstract ( 1463 )   PDF (2170KB) ( 1071 )   The hydrological response to climate change has long been a focus in scientific community. There is an evidence of significant climate change over the past decades in northwest China. It is needed to assess the effects of the change of climate variables on hydrological cycle. In this paper, the daily data of runoff volume, air temperature and precipitation at Bayanbuluk Station in the Kaidu River Basin in Xinjiang during the period of 1980-2010 were collected, and the trend analysis and correlation analysis were used in the study. The result showed that there was an increase trend of average annual runoff volume in recent 30 years. Holistically, there was a slight change of runoff volume during the period from April to June, but an increase during the period from July to September. Runoff formation occurred mainly in summer, the maximum daily runoff volume occurred mostly in spring, especially in April and May. Further analyses showed that there were the significant effects of precipitation during the period from October to next March and temperature increase in spring on the extreme hydrological events in spring. References | Related Articles | Metrics

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Spatial Structure Evolution of Urban System in the Loess Plateau Based on Ecological Carrying Capacity —A Case Study in Qingyang City LIU Hai-Long, SHI Pei-Ji, ZHANG Xue-Bin, ZHANG Hui, WEI Wei 2013, 30 (4):  749-756.  Abstract ( 1281 )   PDF (1734KB) ( 974 )   Qingyang City is located in a hillygully region in the central Loess Plateau, it is arid, and the ecological environment is fragile. In this paper, the spatial structure evolution of urban system in the study area was analyzed based on the ecological carrying capacity. The results showed that there was a traffic directivity in the study area during the period of 1985-2010, and the town development was restricted by the limited traffic conditions. Urban distribution was related to the distribution of water resources, and it was different from different counties. Double center pattern was gradually formed under the optimization of urban system. The ecological elastic degree, carrying capacity of resources and load pressure strength were used in the evaluation. The results showed that the ecological elastic degree and carrying capacity of resources in the study area were holistically in an ascendant trend during the period of 1985-2010. Spatial structure of the regional urban system and the ecological carrying capacity interacted, and the relationship between the ecological carrying capacity and the spatial structure of urban system was discussed. Some measures were proposed for optimizing the spatial structure of urban system in the study area based on the ecological carrying capacity in such fragile ecological environment. References | Related Articles | Metrics

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The Ecological Footprint in Urumqi TONG Xiao-Qin, ZHANG Qing-Hong, XIA Yong, ZHANG Ye, LIU Yue-Fang, PAN Xiang-Liang 2013, 30 (4):  757-763.  Abstract ( 1756 )   PDF (752KB) ( 984 )   In this paper, the Local Ecological Footprint Model was used to calculate the actual ecological footprint, ecological capacity and ecological surplus or deficit in Urumqi during the period from 2000 to 2010. Three important parameters were adjusted based on the average productivity of land in Xinjiang. The results show that the per capita ecological footprint was increased from 5.63 hm2 in 1998 to 24.0 hm2 in 2010, the ecological capacity was decreased from 0.84 hm2 to 0.57 hm2, and the ecological deficit was increased from 4.54 hm2 to 23.04 hm2 The contribution of grasslands to the ecological capacity in Urumqi was the highest, an ecological surplus of grasslands was maintained since 2000, and an ecological deficit of other land types occurred. Ecological deficit of construction land was increased quickly during the period from 2000 to 2010, and the contribution of construction land was up to 93.04% in 2010 because of the population growth and the increase of energy consumption. The land ecosystem development in Urumqi was unsustainable, so some effective measures should be taken so as to reduce the pressure of population growth, improve the average productivity of land, change the mode of economic growth, and develop the recycling economy in Urumqi. References | Related Articles | Metrics

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Urgency of Bedrock Mountainous Hydrogeology Development and Mapping WANG Xin-Feng, LI Wei, WANG Yan, LIU Yun, DENG Qi-Jun, CAO Hong 2013, 30 (4):  764-768.  Abstract ( 1228 )   PDF (646KB) ( 1403 )   The theory of bedrock groundwater has been developed based on the structural conditions along with the development of groundwater exploitation and further understanding of the occurrence and buried conditions of groundwater in mountainous region. Traditional hydrogeological mapping was based on the homogenity theory and the stratabound theory, it was not compatible with the mountainous hydrogeology development neither in guiding the bedrock groundwater exploration effectively. The system thinking and comprehensive application of hydrogeology, structural geology, cartography, GIS and other multidisciplinary knowledge were used in this study. By taking a typical hydrogeological unit in the Taihang Mountain as the research object, the drawing method of mountainous hydrogeology was developed based on the nonuniform ditribution of bedrock groundwater, combination of field investigation and laboratory processing, teamwork and experts[JP8]’i[JP]ndependent thinking, computer cartography and information mining so as to determine the practical and conceptual patterns of mountainous hydrogeological maps. The map of mountainous hydrogeology obtained in this study could be used to explain the occurrence regularity and characteristics of mountaionous groundwater, judge the waterrich belt, provide the basic and guiding information for mountainous hydrogeological mapping, expand the conceptual basis and application space, and serve the national construction. References | Related Articles | Metrics