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Expansion of ürümqi urban area and its spatial differentiation

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Science china Earth sciences 2007年第S1期 159-168页

作者： DONG Wen1,2, ZHANG XiaoLei1, WANG Bin1,2 & DUAN ZuLiang1,2 1 xinjiang institute of ecology and geography, chinese academy of sciences, ürümqi 830011, china 2 Graduate School of chinese academy of sciences, Beijing 100049, china

The expanded area and structure of urban lands and landscape features in ürümqi City are analyzed using rS and GIS means based on the MSS image in 1975 and the TM images in 1990, 1999 and 2002, as well as other related maps. On which the scale, intensity and spatial differentiation of the expansion of the ürümqi urban area during different periods are lucubrated. The results reveal that urban expansion was rapid during the periods of 1949―1965 and 1975―1990, and that it was stable after the 1990s. The urban expansion pattern was significantly different during different time periods: the urban area was expanded outwards based on old districts in a spanned development pattern during the period of 1949―1965; development was stagnant during the period of 1965―1975; urban expansion developed mainly in old districts in a grouped way during the period of 1975―1990. The trend of urban expansion along the traffic lines was obvious, and the direction of urban expansion was dominated by the south-north zonal expansion and supplemented by east-west axial expansion; urban expansion reached the development stage of "multiple centers and multiple districts" after the 1990s, and urban networks were developed more precisely after this time. The sources for urban expansion were mainly cultivated lands, grasslands and unused lands; during urban expansion, the land area devoted to traffic lines, residential areas, dispersive industrial and mineral areas, and garden plots was rapidly enlarged.

关键词： rS & GIS urban land spatial differentiation expansion intensity and pattern

Seedling growth dynamic of Haloxylon ammodendron and its adaptation strategy to habitat condition in hinterland of desert

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Science china Earth sciences 2007年第S1期 107-114页

作者： WEI Jiang1,2,3, ZHANG XiMing1, SHAN LiShan1,2, YAN HaiLong1,2 & LIANG ShaoMing1,2 1 xinjiang institute of ecology and geography, chinese academy of sciences, ürümqi 830011, china 2 Graduate University of chinese academy of sciences, Beijing 100049, china 3 ürümqi Environmental Protection Bureau, ürümqi 830063, china

Through measuring the above/below-ground growth data of Haloxylon ammodendron seedlings at different stages in hinterland of the desert the results show that the *** seedling growth has demonstrated different adaptation characteristics in the continued arid environment with time and space. In May, July, September and October, the growth speed of vertical root is 0.607 cm/d,0.809 cm/d,0.155 cm/d and 0.394 cm/d, respectively; the growth speed of height is 0.093 cm/d,0.076 cm/d, 0.408 cm/d and 136 cm/d, respectively. It is explained that seedlings root system has the growth superiority in space. The maximum growth speed of below-ground (vertical root and horizontal root) of seedling is earlier than that of above-ground (height and horizontal of shoot). In the different periods, the vertical growth speed and the horizontal growth speed of below-ground is 2-10 times and 3-5 times than the height increase speed and the shoot growth speed, respectively. In the whole season, the growth speed of above/below-ground of seedlings shows the alternation growth tendency. At the different periods, the root/shoot ratio of H. ammodendron seedlings is 0.41,0.3,0.39 and 0.88. All these characteristics are the comprehensive performance of seedlings' strategy selection to adapt to the continued arid environment.

关键词： root systems growth speed allocation root/shoot ratio adaptation strategy

Numerical modeling of geothermal groundwater flow in karst aquifer system in eastern Weibei, Shaanxi Province, china

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Science china Earth sciences 2007年第S1期 36-41页

作者： LI Ming1, LI GuoMin1, YANG Liao2, DANG XueYa3, ZHAO ChunHu1, HOU GuangCai3 & ZHANG MaoSheng3 1 State Key Laboratory of Lithospheric Evolution, institute of Geology and Geophysics, chinese academy of sciences, Beijing 100029, china 2 xinjiang institute of ecology and geography, chinese academy of sciences, ürümqi 830011, china 3 Xi’an institute of Geology and Mineral resources, Xi’an 710054, china

The quantitative assessment of geothermal water resources is important to the exploitation and utilization of geothermal resources. In the geothermal water systems the density of groundwater changes with the temperature, therefore the variations in hydraulic heads and temperatures are very complicated. A three-dimensional density-dependent model coupling the groundwater flow and heat transport is established and used to simulate the geothermal water flow in the karst aquifers in eastern Weibei, Shaanxi Province, china. The multilayered karst aquifer system in the study area is cut by some major faults which control the regional groundwater flow. In order to calibrate and simulate the effect of the major faults, each fault is discretized as a belt of elements with special hydrological parameters in the numerical model. The groundwater dating data are used to be integrated with the groundwater flow pattern and calibrate the model. Simulation results show that the calculated hydraulic heads and temperature fit with the observed data well.

关键词： geothermal water numerical modeling fault karst aquifer system Weibei of Shaanxi Province

A contrast of two typical LUCC processes and their driving forces in oases of arid areas: A case study of Sangong river Watershed at the northern foot of Tianshan Mountains

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Science china Earth sciences 2007年第S1期 65-75页

作者： TANG FaShu1,2, CHEN Xi1, LUO GePing1, LIN Qing1,2 & LIU HaiLong1,2 1 xinjiang institute of ecology and geography, chinese academy of sciences, ürümqi 830011, china 2 Graduate University of chinese academy of sciences, Beijing 100049, china

Aerial photographs taken in 1978 and 1987, Landsat TM images in 1998 as well as soil, hydrology and socio-economic data for the oases in Sangong river Watershed were processed by remote Sensing (rS) and Geographic Information System (GIS). There are two typical agricultural land uses in oases, Farm-based Land Use with large-scale intensified agricultural activities (FLU) and Household respon-sibility-based Land Use with small-scale activities (HrLU). The Index Model of Land Use/Land Cover Change (LUCC), Weighted Index Sum (WIS) and logistic stepwise regression model were estab-lished to contrast the two typical LUCC processes and their driving forces. The land use patterns were dominated by cropland and grassland for the entire region, and cropland, residential and industrial land were increasing stably. In the HrLU areas, woodland and grassland declined dramatically, but in the FLU areas, grassland decreased only by 12.0%, whereas woodland increased by 13.7%. LUCC was stronger in the earlier stage (1978-1987) than in the later stage (1987-1998) for the entire region. LUCC was more intense in the HrLU areas than in the FLU areas during the entire period (1978-1998). Policy was a key factor in the land use change, and water resources were a precondition in land use. Under the control of policy and water resources, the main human driving factors included population and economy, and the main natural restrictions were soil fertility and groundwater depth. Human driving factors controlled the land change in the HrLU areas, but natural restriction factors dominated in the FLU areas. In the mean time, intensification of LUCC in the region had some spatiotemporal implications with a fluctuation of impact factors.

关键词： oases land use driving forces Sangong river logistic

Parallels plane projection and its geometric features

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Science china Earth sciences 2007年第S1期 176-180页

作者： ZHOU ChengHu1, MA Ting1, YANG Liao2 & QIN Biao3 1 State Key Laboratory of resources and Environmental Information System, institute of Geographic sciences and Natural re-sources research, chinese academy of sciences, Beijing 100101, china 2 xinjiang institute of ecology and geography, chinese academy of sciences, ürümqi 830011, china 3 Department of Applied Mathematics, Xi’an Jiaotong University, Xi’an 710049, china

A new equivalent map projection called the parallels plane projection is proposed in this paper. The transverse axis of the parallels plane projection is the expansion of the equator and its vertical axis equals half the length of the central meridian. On the parallels plane projection, meridians are projected as sine curves and parallels are a series of straight, parallel lines. No distortion of length occurs along the central meridian or on any parallels of this projection. Angular distortion and the proportion of length along meridians (except the central meridian) introduced by the projection transformation increase with increasing longitude and latitude. A potential application of the parallels plane projection is that it can provide an efficient projection transformation for global discrete grid systems.

关键词： map projection parallels plane projection projection distortion

Study on snowmelt runoff simulation in the Kaidu river basin

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Science china Earth sciences 2007年第S1期 26-35页

作者： ZHANG YiChi1, LI BaoLin1, BAO AnMing2, ZHOU ChengHu1, CHEN Xi2 & ZHANG Xueren3 1 institute of Geographic sciences and Natural resources research, chinese academy of sciences, Beijing 100101, china 2 xinjiang institute of ecology and geography, chinese academy of sciences,ürümqi 830011, china 3 xinjiang Tarim river Basin Management Bureau, Korla 841000, china

Alpine snowmelt is an important generation mode for runoff in the source region of the Tarim river basin, which covers four subbasins characterized by large area, sparse gauge stations, mixed runoff supplied by snowmelt and rainfall, and remarkably spatially heterogeneous precipitation. Taking the Kaidu river basin as a research area, this study analyzes the influence of these characteristics on the variables and parameters of the Snow runoff Model and discusses the corresponding determination strategy to improve the accuracy of snowmelt simulation and forecast. The results show that: (i) The temperature controls the overall tendency of simulated runoff and is dominant to simulation accuracy, as the measured daily mean temperature cannot represent the average level of the same elevation in the basin and that directly inputting it to model leads to inaccurate simulations. Based on the analysis of remote sensing snow maps and simulation results, it is reasonable to approximate the mean temperature with 0.5 time daily maximum temperature. (ii) For the conflict between the limited gauge sta-tion and remarkably spatial heterogeneity of rainfall, it is not realistic to compute rainfall for each elevation zone. After the measured rainfall is multiplied by a proper coefficient and adjusted with runoff coefficient for rainfall, the measured rainfall data can satisfy the model demands. (iii) Adjusting time lag according to the variation of snowmelt and rainfall position can improve the simulation precision of the flood peak process. (iv) Along with temperature, the rainfall increases but cannot be completely monitored by limited gauge stations, which results in precision deterioration.

关键词： snowmelt runoff model (SrM) Kaidu river basin runoff simulation runoff coefficient for rainfall time lag

Multi-scale heterogeneity of soil moisture following snow thawing in Haloxylon ammodendron shrubland

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Science china Earth sciences 2007年第S1期 49-55页

作者： LI Jun1,2, ZHAO ChenYi1, ZHU Hong1,2, WANG Feng1,2, WANG LiJuan1,2 & KOU SiYong1,2 1 xinjiang institute of ecology and geography, chinese academy of sciences,ürümqi 830011, china 2 Graduate School of chinese academy of sciences, Beijing 100049, china

Spatial variation of soil moisture after snow thawing in South Gurbantunggut was quantitatively studied using ANOVA and geostatistics at various scales. The results show that the soil moisture heterogeneity varies along with spatial scales. At the shrub individual scale, there is a gradient in soil moisture from shrub-canopied area to canopy margin and to the interspaces between shrubs. At the community scale, soil moisture is highly autocorrelated and the semivariogram is fitted as spherical model, with an 89.6% structural variance and a range of 4.02 m. In addition, Kringing map indicates that the soil moisture distribution pattern after snow thawing is highly consistent with the shrub patch pattern. At the typical inter-dune transect scale, soil moisture presents a pattern of high value at inter-dune depression and low value at dune, and this variation is fitted as Gaussian model with a structural variance of 95.8% and a range of 66.16 m. The range is comparable with the scale of topography zoning, suggesting that the topography pattern controls the pattern of snowmelt at this scale. The evidence indicates that the heterogeneity of soil moisture at various scales is controlled by various land surface processes after snow thawing. For Gurbantunggut Desert, the spatial heterogeneity of snowmelt at various scales is ecologically valuable, because it promotes the utilization efficiency of the snowmelt for the desert vegetation.

关键词： geostatistics scale spatial heterogeneity snowmelt Haloxylon ammodendron Gurbantunggut Desert

Numerical modeling of geothermal groundwater flow in karst aquifer system in eastern Weibei,Shaanxi Province,china

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Numerical modeling of geothermal groundwater flow in karst a...

The changes of Lop Nur Lake and the disappearance of Loulan

中国科学院地质与地球物理研究所2007学术年会

作者： LI Ming~(1+),LI GuoMin~1,YANG Liao~2,DANG XueYa~3,ZHAO ChunHu~1,HOU GuangCai~3 & ZHANG MaoSheng~3 1 State Key Laboratory of Lithospheric Evolution,institute of Geology and Geophysics,chinese academy of sciences,Beijing 100029,china 2 xinjiang institute of ecology and geography,chinese academy of sciences,(U|¨)r(u|¨)mqi 830011,china 3 Xi’an institute of Geology and Mineral resources,Xi’an 710054,china

The quantitative assessment of geothermal water resources is important to the exploitation and utilization of geothermal *** the geothermal water systems the density of groundwater changes with the temperature,therefore the variations in hydraulic heads and temperatures are very complicated. A three-dimensional density-dependent model coupling the groundwater flow and heat transport is established and used to simulate the geothermal water flow in the karst aquifers in eastern Weibei, Shaanxi Province,*** multilayered karst aquifer system in the study area is cut by some major faults which control the regional groundwater *** order to calibrate and simulate the effect of the major faults,each fault is discretized as a belt of elements with special hydrological parameters in the numerical *** groundwater dating data are used to be integrated with the groundwater flow pattern and calibrate the *** results show that the calculated hydraulic heads and tem- perature fit with the observed data well.

关键词： geothermal water numerical modeling fault karst aquifer system Weibei of Shaanxi Province

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Journal of Arid Land 2010年第4期2卷 295-303页

作者： ZhiChao WANG xinjiang institute of ecology and geography, chinese academy of sciences, Urumqi 830011, china chinese Acad Sci Xinjiang Inst Ecol & Geog Urumqi 830011 Peoples R China

The causes of the disappearance of the ancient town of Loulan in xinjiang, china have been generally agreed to derive from two factors: human activities and natural factors (environmental variations). In this paper, the Muzart Glacier was selected as an example, and found that the length of the glacier has been gradually decreasing and the snow line has been retreating to a higher altitude, both results contributing to a decrease in river flow below the Muzart Glacier. From the distribution of moraines in the Tianshan Mountains and adjacent areas in different periods, the paper speculates that there have been four minor glacial periods since the Quaternary. Although the durations and scales of the four minor glacial periods were different, they all indirectly influenced the formation and disappearance of the Lop Nur Lake. The events of the fourth minor glacial period are the important impact factors in the existence and disappearance of Loulan. Whether the disappearance of Loulan can be related to the events of the three previous minor glacial periods needs further investigation.

关键词： glacier moraine Loulan Lop Nur

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