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  • Original Articles
    Panoramic Location-based Map
    ZHOU Chenghu, ZHU Xinyan,WANG Meng, SHI Chuang, OU Yang
    2011, 30(11): 1331-1335. https://doi.org/10.11820/dlkxjz.2011.11.001
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    Location-based service is one of the key developing areas in modern information society. Linking all kinds of information with their explicit or implicit location(s) greatly promotes the geographical concepts to be more and more accepted and popularized. This paper mainly focused on the discussion on the contents of location based service with location-based map. At first, the authors explained the concept and its contents of location awareness and location computation from the point of view of geographical location and place. Moving location, or the position of a moving object, will be widely adopted and used while positioning system based on GPS and wireless communication are developed. Then, the authors discussed the difference and commonness between location map and general digital map. The semantic location will play key roles in the location-based services. On the basis of state-of-the-art navigation maps widely used in car navigation and internet map service, panoramic location-based map (PLM) is proposed as a new concept and new type of location map. It is a kind of digital map which store all the related data and information about the location and its surrounding events, matter and environment. The user will be served with the information of interest when he or she steps into a certain geographical fence. As location based service is developing and getting popular, PLM will become the most welcome map in the near future.
  • Original Articles
    Cellular Automata Model and Multi-agent Model for the Simulation of Land Use Change: A Review
    GUO Huanhuan, LI Bo, HOU Ying, SUN Tesheng
    2011, 30(11): 1336-1344. https://doi.org/10.11820/dlkxjz.2011.11.002
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    Land use change simulation study is an important branch of the land use change research. The development of the complex system theory and simulation platform makes more and more complex system simulation methods used in the research of land use change. Cellular automaton model and multi-agent model are designed based on complex system theory. We introduce the development of the land use change simulation studies in this paper. We find that the mechanism of land use change is a complex system which is composed of individuals, community, resource and envrionment. Then, we discuss the meaning, main topics, simulation platform, advantages and limitations of cellular automaton model and multi-agent model. We also recommend future directions for land use change simulation research, which include the theoretical research, CA and MAS integration, and transition rules or decision making. It is significant to design a simulation platform suitable for China.
  • Original Articles
    A Coupled Surface-water/Groundwater Model for Haihe River Basin
    WANG Zhonggen, ZHU Xinjun, LIWei, LUO Yuzhou, ZHANG Minghua
    2011, 30(11): 1345-1353. https://doi.org/10.11820/dlkxjz.2011.11.003
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    The Haihe River Basin covers 318 200 km2 in northern China, consisting of mountains and plateaus in the north and west, and the North China Plain in the eastern and southern parts. With rapid population growth and economic development, the combined problems of water shortage and water contamination significantly constrain the sustainable development in this area. At present, severe over-exploitation of groundwater was observed in the Haihe River Basin, with about 2/3 of the water supply relying on groundwater. In order to strengthen the unified management of groundwater and surface water, we need to develop coupled hydrologic modeling of surface- and groundwater which provides essential technical supports in the management planning of the Haihe River Basin. This article discussed existing modeling structures for coupled surface water and groundwater simulations. Loose coupling of SWAT model (for surface water simulation) and MODFLOW (for groundwater simulation) was developed based on the consideration of management-oriented application and data availability. The results of model evaluation indicated that, the newly developed modeling framework, integrated with GIS platform, reasonably captured the spatiotemporal variability of the hydrological processes of the surface water and groundwater in the study area. This article built a coupled SWAT/MODFLOW model for the Haihe River Basin. For surface water simulation, the study area was divided into 283 sub-watersheds, and further into 2100 hydrologic response units (HRU) based on land use and soil maps. For groundwater simulation, grid system of 4 by 4 km2 was established for the 15 major lithologic regions. In a GIS-based platform, the groundwater grids were geo-referenced to corresponding overlying HRUs. The modeling results showed a good agreement with the measurements of surface water and groundwater during 1995-2004. Results of model evaluation indicated that the developed model could be a promising tool in watershed management planning under the context of global climate change and the“South-NorthWater Transfer Project”.
  • Original Articles
    Variations of the Hydrological Characteristics and Driving Factors in the Yihe River Basin
    XUE Lifang, TAN Haiqiao
    2011, 30(11): 1354-1360. https://doi.org/10.11820/dlkxjz.2011.11.004
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    Taking the Yihe River basin as a study region, this paper analyzes the variations of hydrological characteristics such as precipitation, runoff and peak discharge, during the period 1951-2002. Time series analysis methods, such as the Kendall method and orderly cluster analysis are used to test the change trend and the mutation of precipitation-runoff. The influences of climate change and human activities on runoff were examined quantitatively based on the comparison between the observed runoff and regression simulation data of the natural runoff at Linyi hydrological station. Some conclusions are drawn as follows. (1) During recent 50 years, the Kendall test value of the annual precipitation is -1.028 at Linyi hydrological station, showing that the precipitation decreased slightly. However, the value of annual runoff is -3.689, decreased evidently, and monthly runoff shows the same trend. That is the responses of runoff to precipitation tend to be weak. But the change trend of rainstorm runoff shows that single storm-runoff keeps strong consistency with rainfall. (2) Based on the runoff mutation, the annual precipitation-runoff process can be divided into three periods, 1951-1964, 1965-1975, and 1976-2002. In the 10-year scale, the observed runoff shows a relatively consistent trend with rainfall. To some extent, precipitation controls the evolution of runoff. (3) Since the mid-1960s, the mean annual runoff at Linyi hydrological station decreased by 148.8 mm, accounting for 51.6% of the mean annual natural runoff. The contribution rate of climate change and human activities to runoff reduction is 39.3% and 60.7%, respectively. The human activities, such as hydraulic engineering construction, land use and land cover change and water resources development, have a profound impact on runoff. The river basin sustainable development requires reasonable constraints to human activities to comply with the nature law of hydrological cycle.
  • Original Articles
    Advances in the Research Methods of Abrupt Changes of Hydrologic Sequences and Their Applications in Drainage Basins in China
    ZHOU Yuanyuan, SHI Changxing, FAN Xiaoli, DU Jun
    2011, 30(11): 1361-1369. https://doi.org/10.11820/dlkxjz.2011.11.005
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    Detecting abrupt changes in hydrologic sequences plays an important role in discriminating the impacts of climate change and human activities. In recent decades, researches on abrupt changes of hydrologic sequences have advanced greatly in China from using only one method in the earliest stage to applying diagnosis system of multiple methods and improved methods in the study in the late stage. Different results were given by studies using different methods and/or different time series of hydrologic sequences in the same drainage basins. In this paper, the theories of methods determining abrupt changes in hydrologic sequences and their application in the main watersheds in China are reviewed in order to provide reference for further development of these methods and their applications.
  • Original Articles
    Progress in the Study of Extreme Hydrologic Events Under Climate Change
    ZHANG Liping, DU Hong, XIA Jun, XU Xia
    2011, 30(11): 1370-1379. https://doi.org/10.11820/dlkxjz.2011.11.006
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    Extreme hydrologic events such as floods and droughts caused by abnormal climate change and increased risks of water disasters are becoming the major challenges to the survival of the people survival. In recent years, the research on the change trend, mechanisms, response and prediction of the climate change of the extreme hydrologic events in basins under climate change is drawing more and more attention from the scholars at home and abroad. This paper begins with the definitions of extreme hydrologic events, and then analyzes and reviews the research methods, and hydrologic extreme value distribution, as well as the observation and simulation of extreme hydrologic events. On this basis, this paper makes a discussion on the problems in the present research. The directions of further research are also provided.
  • Original Articles
    Temporal and Spatial Variations of the Drought in the Warm Half Year over Northern China
    LIU Lihong, ZHAI Panmao, ZHENG Zhuguang, LIU Xiaoling
    2011, 30(11): 1380-1386. https://doi.org/10.11820/dlkxjz.2011.11.007
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    Daily precipitation data from 348 stations in northern China are selected to construct the time series of the periods of the longest consecutive dry days in the warm half year (April-September) that is divided into four sub-regions. The empirical mode decomposition (EMD) method is used to obtain intrinsic mode functions (IMFs) by which variations are analyzed at various time scales. Based on wavelet analysis and other methods, sudden jump points are found. Results show that the variation of the longest consecutive dry period is mainly composed of two higher frequency intrinsic mode functions, and their contribution ratio is 80% to the total variance. This shows that 3-4 year and 7-8 year oscillations play important roles. Lower frequency components reflect the inter-annual variation of about 10 years. There is an increasing trend of the longest consecutive dry period in the warm half year in northeast China, north China, and eastern part of northwest China, and the droughts in most of northern China are increasing, but decreasing in the western part of northwest China. For the last 10 years, it get drier in northeast China, while it gets wetter in the eastern part of northwest China. The significant increase of the longest consecutive dry periods observed in north China in 1992 and in northwest China in 1960 was associated with the droughts. The results obtained may be different from each other owing to the differences in temporal and spatial scales.
  • Original Articles
    Spatial Distribution of δ18O in China's Precipitation Based on a Secondary Variable of Temperature
    LI Yaju, ZHANG Mingjun, WANG Shengjie, LI Zhongqin, LI Xiaofei
    2011, 30(11): 1387-1394. https://doi.org/10.11820/dlkxjz.2011.11.008
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    To acquire knowledge of temperature effect on stable isotope, the relation between various temperature related variables and isotopic composition of modern precipitation was explored, based on the high-resolution meteorological data and the isotope values from WorldClim and China's stable isotope observation sites. We used a linear model to fit the relation between the different temperature variables and the isotopic composition. Although the annual mean temperature does well to explain the annual mean isotope signal, the better correlation between the mean temperature in the hottest quarter and the annual mean isotope of 63 sites in China is found (R2=0.79). The temperature during the coldest quarter is used as an ancillary variable in simple kriging with varying local means (SKlm). In SKlm, the residual isotope values from the regression with mean temperature in the hottest quarter are kriging interpolated, which are then added to the high-resolution spatial distribution of stable isotope (δ18O) in China's precipitation. So more local isotope effects are accounted for by the spatial interpolation of the residual isotope values. With the good correlation between mean temperature in the hottest quarter and annual mean isotope values, the spatial distribution map can well present the pattern of variability of isotope in China. The low prediction error and a symmetrical distribution of the differences between the true and predicted values demonstrate the successful application of the SKlm approach. In summary, using surface temperature as a factor does improve the prediction of the China's isotope variation in precipitation compared to a combination of latitude and altitude, and also indicates the environmental background of regional climate and local geographic factor.
  • Original Articles
    Climatic Characteristics of Extreme Rainstorm Events in Hunan Province during 1960-2009
    ZHANG Jianming, LIAO Yufang, DUAN Lijie, ZENG Xianghong
    2011, 30(11): 1395-1402. https://doi.org/10.11820/dlkxjz.2011.11.009
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    Using 1960-2009 daily precipitation data of 89 stations, the spatio-temporal distribution of extreme rainstorm events in Hunan Province in recent 50 years is analysed by linear regression, abrupt change analysis and wavelet analysis. The results showed that the intensity and frequency of rainstorm events increased in the last 60 years. Extreme rainstorm events showed a wave-increase: low in the 1960s and 1980s whereas high in the 1970s and 1990s. A abrupt change (from dry to wet) can be observed from the late 1980s to early 1990s. In addition, the extreme rainstorms also occurred in cycles of 2-year, 5-year, 7-year, and 21-years. Generally, the numbers of rainstorms and the associated precipitation of May to August are significantly higher than the average. Precipitation of the western Hunan shows a decreasing trend, while that of the northern and central Hunan is increasing. The eastern and southern Hunan may become much drier. Extreme rainstorm shows a increasing trend, while that of the southwestern, northwestern and central Hunan shows a decreasing trend.
  • Original Articles
    Physical Characteristics of Forest Snow in the Western Tianshan Mountains, China
    LU Heng, WEIWenshou, LIU Mingzhe, HAN Xi, HONGWen
    2011, 30(11): 1403-1409. https://doi.org/10.11820/dlkxjz.2011.11.010
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    The special physical characteristics of snow cover have great influences on the ice-snow hydrological process, snow ecosystem and different scale climate systems. Presently, the physical characteristics of snow cover in the forest are less investigated, so it is meaningful to measure the height, sedimentation rate, density and water content of the seasonal snow in the forest of picea schrenkiana in the Tianshan Mountains. The results show that the snow depth under crown is less than the observation site, the sedimentation rate of snow under crown is less than the observation site, and the rate in the stable period is less than the snowmelt period. The snow density under the tree is significantly lower than the observation site. The snow density of the upper and bottom layers is smaller than the middle layers. The maximum value of snow density is located in the firn-snow layer under the tree, but the maximum value is located in the coarse-grained snow layer in the open area. The snow density in the snowmelt period is greater than in the stable period. In the stable period, the profile of snow liquid water with depth has a single peak in the observation site, the liquid water content of the coarse-grained snow is the highest, and the liquid water content increases with depth under the tree. In the snowmelt period, the liquid water content of the fine-grained snow is the highest, the liquid water content of the newly fallen snow has the minimum value. The snow liquid water content in the open ground decreases with depth from fine-grained snow to mid-grained snow, and increases with depth from coarse-grained snow to depth hoar, while the water content decreases from fine-grained snow to depth hoar under the tree. The diurnal variation is to decrease with depth in the stable period, and the variation of snow liquid water content in open ground is greater than that under the tree. The maximum diurnal variation is in the layer of fine-grained snow and decreases with depth; the liquid water content of new snow and firn-snow in open ground is greater than that under the tree, but the layer of coarse-grained snow and depth hoar are on the contrary.
  • Original Articles
    The Analysis of Temperature Trend Based on Fractal Theory and GIS Technology in Shandong Province
    ZHANG Qingwei, SHI Chun, WANG Jun, XU Shiyuan
    2011, 30(11): 1410-1414. https://doi.org/10.11820/dlkxjz.2011.11.011
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    Many researches have proved that temperature has ascended. It is known that temperature is closely related with living beings. Because the amounts of plants and animals are reduced sharply, the trend of temperature becomes the research hotspot under the natural and human impacts. Based on the temperature data of 117 meteorological stations from 1970-2007 in Shandong Province, R/S analysis in fractal theory is adopted to research the changing trend in temperature. Then GIS technology is employed to study the characteristics of temperature change in recent 40 years. The results show that the chance in which H index is not equivalent to 0.5 is 100%, demonstrating the temperature of this province is changing trend. Temperatures of spring, summer and winter will keep a rising trend. The distribution of isothermals turns to be random and the local microclimates will develop which can be partly explained by human influence.
  • Original Articles
    Spatial Heterogeneity and Air Pollution Removal by Green Space in Greater Pearl River Delta
    DING Yu, LI Guicai, LU Xu, Gao Mei
    2011, 30(11): 1415-1421. https://doi.org/10.11820/dlkxjz.2011.11.012
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    With rapid urbanization, the importance of air pollution removal by regional green space had been widely accepted. Therefore, the concept of spatial heterogeneity and ecological function were applied to regional management and spatial planning. This article took the view of spatial heterogeneity, and analysed the relevant factors and discrimination method. The current study established the correlation between air pollution reduction effect and spatial characteristics, which revealed the impact of spatial heterogeneity on vegetation. The study showed that the relative effects of regional forest cover in reducing air pollutant concentrations in the atmosphere of SO2, NO2, and PM10 were 1.3%, 0.7% and 4.1%, respectively, which varied in different sub-regional air quality improvement. Pollutant removal rates in moderate ability subregion was obviously higher than that in high-ability subregion and low-aridity subregion. However the driving force of ecological function in moderare aridity subregion was still at the level of pollution-driven stage, compared with the other two subregions at the levels of green feature-driven stage. Therefore, the effects of biological diversity, ecological structure and landscape pattern on ecological function were more prominent. Finally, some problems were pointed out and function- oriented research was proposed as the main development trend in the future.
  • Original Articles
    Accuracy Test for the Application of GDAS Data and NOAH Land Surface Model to China
    TIAN Jing, SHU Hongbo, SUN Xiaomin, CHEN Shaohui
    2011, 30(11): 1422-1430. https://doi.org/10.11820/dlkxjz.2011.11.013
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    At present, GDAS atmospheric forcing data is widely used as the inputs in the simulation of water and energy cycles. Besides the problem of the model itself, these forcing data determine the accuracy of the simulation. Although there are obvious uncertainties and low spatial resolution for these data, most of researches still used them to perform the simulation of land surface process because no better way can be used. The purpose of this paper is to test the accuracy of the results simulated by NOAH land surface model taking GDAS atmospheric forcing data as the inputs and gives the objective evaluations, which has important reference value for the users of the data and the model. The test results obtained on the basis of the observation data from Yucheng, Xilinhaote and Changbaishan ecological observation sites showed that the accuracy of shortwave net radiation and total net radiation in GDAS dataset are very good. It is reliable in the applications. Large differences were found between precipitation data in GDAS dataset and those from the three sites; however, there is good consistence between their precipitation times. Considering the effect of scale difference between GDAS and measurement on the validation, and the lack of the spatial precipitation data, this data is also worth of application. In addition, there are also good consistence between the change trend of latent heat flux, sensible heat flux and the top soil water content simulated by NOAH and that by measurements, and the simulated results can truly reflect the change process of surface situation although there are large difference between their absolute values. Poor accuracy was found in simulated soil heat flux.
  • Original Articles
    Research Advances on Changes of Leaf Traits along an Altitude Gradient
    SONG Lulu, FAN Jiangwen, WU Shaohong
    2011, 30(11): 1431-1439. https://doi.org/10.11820/dlkxjz.2011.11.014
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    A variety of environment factors show continuous gradient changes under an altitude gradient, so it is very significant to reveal the responses of the plants traits under the climatic change under altitude gradient and the results can also provide an foundation to understand the relationship between the terrestrial ecosystem and the global change. This article puts emphases on the changes of leaf span, specific leaf area, leaf nitrogen content, chlorophyll, stomata conductance, carboxylation efficiency, water use efficiency and leaf δ13C along an altitude gradient. This article also explores some uncertainties on the interpretation of mechanisms of leaf traits along the altitude gradient. This review provides a good knowledge for directing the relevant studies in China.
  • Original Articles
    Growth of Urban Construction Land: Progress and Prospect
    WANG Jing, FANG Chuanglin
    2011, 30(11): 1440-1448. https://doi.org/10.11820/dlkxjz.2011.11.015
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    Along with the rapid growth of urban construction land, cultivated land decrease and low level of availability of urban construction land in China, the paper reviewed the domestic and international research progress on the growth of urban construction land in order to provide reference for deepening the research, solving land-use problem, and guiding urban construction land development and healthy urbanization. At present, there are many comprehensive and typical studies at different scales and in various regions on the growth of urban construction land including characteristics, factors and dynamic mechanism of the spatial-temporal process, simulation and forecast, discussion about arable land loss, and the strategies and methods. Quantitative analysis methods include mathematical statistics, RS and GIS, grey system analysis, and MAS and CA model. All of the researches above play an important role in in-depth understanding and control of the growth of urban construction land. In the future, attention should be paid to studies on urban-rural system, and the research methods should be changed from one dimension to two and three dimensions or multidimensions. In addition, intensive urban land use should be encouraged and inefficient and fast expansion of urban construction land uses should be controlled.
  • Original Articles
    Evaluation for Cultivated Land Resources Security of China in 2007
    SONGWei, CHEN Baiming, SHIWenjiao, WU Jianzhai
    2011, 30(11): 1449-1455. https://doi.org/10.11820/dlkxjz.2011.11.016
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    14 indexes about quantity security, quality security and ecological security were selected to evaluate the cultivated land resources security (CLRS) of China in 2007. The data were derived from the land use survey and the reports of agricultural land classification from the Ministry of Land and Resources of China, the Second National Soil Survey (1978) and National Bureau of Statistics of China. The results can be concluded as follows. (1) the CLRS of China is not high in 2007 with a score of only 0.517. Among the four regions, the evaluation value of CLRS is higher in eastern China but lower in western China. At provincial level, the scores of CLRS of Xinjiang and Tibet in Western China and 10 provinces of eastern China, such as Shandong, Fujian, Zhejiang, is higher than those of the others. Provinces with lower scores of CLRS are mostly distributed in Western China, including Shaanxi, Inner Mongolia, Gansu, Qinghai, and Ningxia. (2) The quantity security score of CLRS in China is 0.195, higher in Northeast China but lower in regions of Loess Plateau, North China Plain and Sichuan Basin. The quick loss of cultivated land caused by construction occupation and the policy for grainto- green and the high inventory of cultivated land in 2020 under the consideration of regional tasks for grain production are the main reasons resulting in the low quantity security score of CLRS in the three regions. (3) The quality security score of CLRS in China is 0.171, higher in Northeast China but lower in eastern China. Natural land quality is the key factor affecting regional quality security. (4) The ecological security score of CLRS in China is 0.171, higher in Northeast China but lower in eastern China. Eco-environmental problems caused by excessive use of chemical fertilizer, agricultural pesticide and agricultural film are the main reasons leading to lower ecological security in eastern China, but soil and water erosion is the key reason for western China.