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  • Original Articles
    Progress in Precipitation Chemistry in Cryosphere Regions of Western China
    LI Xiangying, QIN Dahe, HAN Tianding, CHENG Peng
    2011, 30(1): 3-16. https://doi.org/10.11820/dlkxjz.2011.01.001
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    Atmospheric precipitation chemistry is a credible indicator describing the anthropogenic influence on atmospheric environment. Chemical compositions in snow and ice in high-elevation regions play an important role on environmental change on regional and global scales and its evolution process. Precipitation studies in cryosphere regions of western China began in the late 1970s, and many results have been achieved, in particular those about precipitation data obtained from snow cover and ice core. This paper reviewed the research history and major results of precipitation chemistry in China. In addition, it is necessary to establish long-term and systemic monitoring stations that represent regional precipitation characteristics combined with the Global Atmospheric Observation Network, China Acid Rain Observation Network, and the observation stations of Chinese Academy Sciences, and it is important to collect snow cover and ice core samples to supplement dataset of precipitation chemistry in high-elevation regions. Moreover, we should strengthen studies on trace element, organic acid, POPs and so on in precipitation based on the advanced-analysis technology (mass spectrum, gas chromatography-mass spectroscopy and the like) to supply more evidences to anthropogenic influence. Furthermore, it is also necessary to attach importance to the present-process research of atmospheric aerosol-snow cover-ice core, which plays an essential role in establishing a spatial distribution model of atmospheric precipitation chemistry in the cryosphere regions of western China.
  • Original Articles
    Research Progress in Dry/wet Climate Zoning
    MAO Fei, SUN Han, YANG Honglong
    2011, 30(1): 17-26. https://doi.org/10.11820/dlkxjz.2011.01.002
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    Dry/wet climate zoning is an important part of climatology, geography, ecology, and agriculture.?Since 1900, great progresses in grading of dry/wet climate and indexes for dry/wet climate zoning and their calculating methods have been achieved by scholars at home and abroad. In this article, the achievements in scientific research in recent more than 100 years were summarized, including indexes for dry/wet climate zoning, calculating methods of reference evapotranspiration, and grading of dry/wet climate zoning and their naming methods. The existing scientific issues for this subject were put forward.
  • Original Articles
    Reviews on Regional Climate Change Vulnerability Assessment
    YU Ou, YAN Jianzhong, ZHANG Yili
    2011, 30(1): 27-34. https://doi.org/10.11820/dlkxjz.2011.01.003
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    Assessments of regional vulnerability provide a scientific basis for poverty reduction, sustainable development and formulation of adaptive strategies in vulnerable regions. Quantitative methods for regional vulnerability assessment are very difficult due to the complexity of man-land system. Vulnerability studies started late in China, and the earlier studies concerned more on the distribution of vulnerable areas but less on vulnerable people, which prevents the central and local governments from formulating scientific adaptation policies and measures. This paper reviews the understandings of vulnerability and the methods for regional climate change vulnerability assessment. Cases about qualitative analysis, index evaluation and vulnerability evaluation based on sustainable livelihood framework and GIS methods are introduced. Suggestions on vulnerability assessment based on sustainable livelihood framework are also presented for the vulnerable regions of China.
  • Original Articles
    An Overview and Perspective about Causative Factors of Surface Urban Heat Island Effects
    XIE Miaomiao, WANG Yanglin, FU Meichen
    2011, 30(1): 35-41. https://doi.org/10.11820/dlkxjz.2011.01.004
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    Urban heat island (UHI) is a hotspot in the study about urban ecological and environmental effects. UHI effects are caused by multiple factors, and the synthesized mechanism study can supply a foundation to release the negative effects of UHI. This study proposes a theory framework for causative factors of surface urban heat island (SUHI) by analyzing the process of surface energy on the basis of landscape ecology. Since surface temperature represents the process of surface energy, we examine the causative factors of this process, which includes energy absorption/emission, energy translation, and energy transmission. The internal and external progresses on each kind of causative factors are reviewed in this study. We also compare the internal studies on synthesized mechanism of SUHI with external studies. By the comparison of progresses of causative factor studies and the mechanism of SUHI, we deduce the prospect on this field.
    The energy absorption and emission of surface represent the ability to absorb solar short-wave radiation, and the capacity to emit earth’s surface long-wave radiation, which are controlled by the physical properties of land surface. The studies on this theme focus on land use and biophysical properties. It has reached a consensus on the functions of land use/land cover. The biophysical properties can better describe the relationship between surface characteristics and temperature with higher accuracy. The physical properties of the surface include vegetation, impervious surface, and surface moisture, which are represented by land cover indices derived from remote sensed data including NDVI, ISA, NDBI, NDMI, etc. Energy translation is the process of translating one form of energy into another, which, in this case, is surface heat determined by the intensity of human activities. Population density, energy consumption intensity, and automobile flux are normal indices to depict the intensity of human activities. However, the studies in this field are limited by the spatial resolution of social-economic data. Energy transmission represents the energy flow between different patches referring to the temperature gradient, which primarily depends on the spatial relationship between landscape patches. Two themes in this field have been developed. One is the relationship between temporal heterogeneity of landscape patterns and surface temperature changes. The other is the influence of spatial characteristics of landscape patches on surface temperature. In the field of synthesized causative factors, the external study focuses on the triangle model of temperature, vegetation, and soil moisture. Most of the internal analyses are about the statistical model consisted of land cover and social-economic components.
    There are two tendencies of the relating studies in the future. Firstly, high resolution data and field survey data will promote the study on the analysis of energy translation and transmission. Secondly, following a description of energy process, we can involve social-economic indicators and landscape patterns in the triangle mechanism model to establish the systemized mechanism of SUHI.
  • Original Articles
    Research Progress and Application of Step-pool Systems in Mountain Streams
    YU Guoan, HUANG Heqing, WANG Zhaoyin, YAO Zhijun
    2011, 30(1): 42-48. https://doi.org/10.11820/dlkxjz.2011.01.005
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    Step-pool systems are a common geomorphologic configuration in high-gradient mountain streams (> 3%-5%) with alternating steps and pools having a stair-like appearance. Step-pool systems are very effective in dissipating flow energy and stabilizing riverbeds, and is an ecologically-sound riverbed pattern in mountain streams, thus it is an important streambed structure and micro-morphologic configuration for high-gradient mountain streams. Extensive research has been carried out on step-pool system since the 1980s through field investigation, flume experiment and mathematic model analysis. The research focused on step-pool development of environmental conditions, configuration feature, formation mechanism, and its hydraulic, geomorphologic and ecologic functions. Step-pool system and similar streambed structures have been applied to mountain stream restoration and stabilization in many countries in recent years, and have shown positive results. This paper synthesizes the recent literature and application cases of step pool, and discusses the possible research directions in the future.
  • Original Articles
    Response of Wetlands Rise and Fall in the Changjiang River Source Region to Climatic Change
    LI Fengxia, FU Yang, XIAO Jianshe, SHI Xinghe, LIU Baokang
    2011, 30(1): 49-56. https://doi.org/10.11820/dlkxjz.2011.01.006
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    The Changjiang River Source Region is located in the hinterland of Qinghai-Tibet Plateau and in the north of Tanggula Mountain. Because the direct impact of human activities is limited, critical information can be found from the inter-related climate change and wetlands rise and fall. The impacts of climate change on the wetlands of the Changjiang River can be reflected. According to Gray correlation analysis, it can be found that evaporation plays an dominant role in the rise and fall of the total area of wetlands compared to other climatic factors, followed by the impact of precipitation. Climate in summer affects the rise and fall of wetlands more prominently than that in other seasons. The Changjiang River has a tendency of temperature rise, precipitation increase, and evaporation decrease, and it has a warm and humid trend since 1990. Its annual precipitation has been declining and its annual evaporation has an increasing trend in the 21st century. These are the significant driving forces for the rise and fall of wetlands. According to the remote sensing analysis, the total area of wetlands in the Changjiang River Source Region was increased by 353.22 km2, and the annual average increasing rate was 35.32 km2/a during 1990-2000, while it was reduced by 20.57 km2 during 2000-2004. These two periods showed the close relations between wetlands rise and fall and corresponding climate change.
  • Original Articles
    Quantitative Error Assessment of Topographic Wetness Index Algorithms
    BAO Lili, QIN Chengzhi, ZHU Axing
    2011, 30(1): 57-64. https://doi.org/10.11820/dlkxjz.2011.01.007
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    Topographic Wetness Index (TWI) is a widely-used topographic attribute which can predict the control of terrain on spatial distribution of soil moisture. Diverse TWI algorithms might get very different results; therefore, it is necessary to assess the algorithms. Traditional error assessment method applies TWI algorithms to 'real-world' DEM, but the error from DEM quality might interfuse the error from algorithms and thus influence the accuracy of evaluation. To solve the problem, this paper proposes an assessment method of error from TWI algorithm with artificial DEMs which can avoid data source error. Four typical TWI algorithms, i.e. TWI algorithm based on a typical single flow direction algorithm (D8), TWI algorithm based on a typical multiple flow direction algorithm (FD8), TWI algorithm based on an adaptive multiple flow direction algorithm (MFD-md), and TWI algorithm using MFD-md in which the maximum downslope, instead of traditional slope gradient, is used to estimate the tanβ in equation of TWI, are evaluated by the proposed assessment method. First, four artificial surfaces are constructed to simulate typical compound terrain conditions, i.e. convex-centred slope, concave-centred slope, saddle-centred slope, and ridge-centred slope, respectively. Secondly, the artificial surfaces are converted to three sets of artificial DEM data with different cell size (1 m, 10 m, and 30 m) to apply TWI algorithms to compute TWI. Third, the theoretical TWIs for every artificial surface are calculated to quantitatively assess the error from TWI algorithms based on RMSE. Assessment result shows that TWI algorithms based on multiple flow direction algorithm (MFD) perform better than TWI algorithm based on single flow direction algorithm (SFD), i.e. D8, under terrain conditions of convex-centred slope, concave-centred slope and saddle-centred slope. Under ridge-centred slope terrain condition, the result of TWI algorithm based on SFD is just inferior to the result of TWI algorithm which combines MFD-md with maximum downslope algorithm. As the resolution becomes coarser, errors of TWI algorithms based on MFD become larger on the whole, while the trends of results of TWI algorithm based on SFD vary with different terrain conditions. The proposed quantitative assessment method for TWI algorithm can be similarly used to assess algorithms of other compound topographic attributes, such as specific catchment area, stream power index, and so on.
  • Original Articles
    The Analysis of Climate Decadal Change Characteristics and Urban Climate about Chuxiong City of Yunnan Plateau during 1960-2009
    HE Ping, LI Hongbo, HUANG Hui
    2011, 30(1): 65-72. https://doi.org/10.11820/dlkxjz.2011.01.008
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    By comparison of the data(1960 to 2009) of Yunnan Chuxiong and Nanhua and shuangbai in Yunnan plateau which consist of temperature, precipitation, relative humidity, low cloud and other weather data, And then use conventional anomaly method, 3-order polynomial fitting trend method, 5-year moving average method to analyze the decadal characteristics and the urban climate , Otherwise use gray interrelated analysis to understand the factors which influce the urban climate. It is found that the temperature of urban area has reduced before the 80s of the 20th，however , it has been rising since 80s. Otherwise the difference of temperature between urban with suburban has been becoming more and more obvious since 80s, All show that the urban heat island effect in Chuxiong has been getting more and more obvious since 1980’s and the urban dry island is forming now because of the average relative humidity is reducing ,what’s more，the amount of annual precipitation and average low cloud in city are more than other two station，which also shows that the urban rain island has formed yet .
  • Original Articles
    Comparative Research on the Precipitation Variation in the Regions Susceptible to Global Climate Change in China——A case study in Heilongjiang, Xinjiang and Tibet
    HAO Chengyuan, ZHAO Tongqian
    2011, 30(1): 73-79. https://doi.org/10.11820/dlkxjz.2011.01.009
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    The study on regional response to global climatic changes in China has arouse concerns while the research on global climatic change has been one of major issues in current natural science over the past 40 years. According to the daily precipitation data from 93 national meteorological stations from 1961 to 2008, the comparative studies were made on the variation process and the characteristics of both annual precipitation and seasonal precipitation among Heilongjiang, Xinjiang and Tibet. Firstly, the annual precipitation of Heilongjiang is decreasing gradually while that of Xinjiang and Tibet is increasing, especially after 1995. The increasing tendencies of Xinjiang and Tibet are very instinct. Secondly, the growth is different although the precipitation of the three provincial units all have increasing trends in winter and spring. Xinjiang has the largest growth, followed by Heilongjiang, and Tibet has the smallest increase in spring, and the largest increase in winter. But the changing tendencies are not instinct. Thirdly, the variation trends of the rainfall in summer and autumn are the same as the annual precipitation with slight decrease in Heilongjiang and slight increase in Xinjiang and Tibet. The increasing tendencies are very instinct. Fourthly, 61.5% of the meteorological stations in Heilongjiang show obvious changes in winter and 64.7% of the stations in Tibet have such changes in spring, while 20 of the stations in Xinjiang present instinct changing tendencies in annual precipitation. Fifthly, both annual and seasonal precipitations have obvious changes in Xinjiang and Heilongjiang and are relatively stable in Tibet.
  • Original Articles
    Response of Simulated Stream Flow to Soil Data Spatial Detail across Different Routing Areas
    LI Runkui, ZHU A-Xing, LI Baolin, PEI Tao, QIN Chengzhi
    2011, 30(1): 80-86. https://doi.org/10.11820/dlkxjz.2011.01.010
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    Appropriate spatial detail of input data for watershed modeling is partly dependent on the scale of the watershed modeled. It will facilitate data selection for modeling if the effect of watershed scale can be quantitatively described. This paper aims at investigating the variations of simulated differences between different soil data across a series of water routing areas. The study was conducted using soil and water assessment tool, with the 1:24,000 SSURGO soil data and digital soil mapping data from Soil Land Inference Model (SoLIM) at 10m resolution as different input data, to investigate the stream flow differences arising from different soil data at Brewery Creek, Dane county, Wisconsin of the USA. Results show the low consistency of simulated stream flow between the two soil data at small water routing areas, but the consistency generally rises with the increase of routing area. Simulated stream flow based on SSURGO and SoLIM becomes similar especially for area larger than 10 km2. Based on the effects of continuous routing scales on simulated stream flow differences between different soil data, a preliminary conclusion can be made that coarser input data can also be used for a larger watershed for stream flow simulation.
  • Original Articles
    Responses of the Surface Water and Groundwater to Precipitation in the Loess Hilly-gully Region:A Case Study of Kanggou Watershed
    DANG Lijuan, XU Yong, XU Xuexuan
    2011, 30(1): 87-94. https://doi.org/10.11820/dlkxjz.2011.01.011
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    The construction of eco-system in the loess hilly-gully region which was based on de-farming and afforestation policy has made remarkable improvement in the past decade. To probe into the relationship between precipitation and surface water and groundwater since the de-farming and afforestation policy was implemented, taking the Kanggou watershed in Yanan as an example, based on the daily meteorology data from Yan'an station during 1997-2006, and the actual measured data of runoff, spring flow, well level, landforms and land-use, this study was conducted by correlation analysis and GIS spatial analysis. This paper analysed the spatio-temporal variation of precipitation, surface water and groundwater in Kanggou watershed, explored the relationship between precipitation and surface runoff, and groundwater runoff, and revealed different responses to the precipitation of the surface water and the groundwater. Results are as follows: (1) There is a close connection between runoff and precipitation. The largest surface runoff occurs in the wet season with the peak precipitation. The distribution of precipitation and the surface water is basically consistent all the year. The runoff concentrates in May to September, accounting for 66.83% of the total annual runoff. The surface runoff forms a curve with peak and valley in turns, having a single peak with limited precipitation and double peaks with abundant precipitation. (2) There is a clear difference of surface runoff between morning and afternoon in the same day, and the difference between noon and afternoon is small. The average difference of surface runoff is 21.16 m3/d. The annual surface runoff varies significantly. One of the possible reasons is the difference of the wet year, normal year and dry year caused by the recharge of precipitation, and the other reason is the effects of eco-environment management in recent years. (3) The amount and the seasonal distribution of the precipitation directly affect the springs and wells, and wells are more sensible than springs under the same conditions. The response time of the wells to rainfall recharge is as long as 22 to 30 days, and the response time of springs is only 7 to 10 days. The reason is that groundwater runoff flow in rock gaps and soils is very slow. Also, the groundwater system contains giant storage vacuum, which makes permeation and discharge become limited. So the system relies on the concentrated or discontinuous recharge by precipitation as the only source of the storage, and then recharges to the other aquifers when seasons change.
  • Original Articles
    Scale Effect of Runoff and Sediment Reduction Effects of Soil and Water Conservation Measures in Chabagou, Dalihe and Wudinghe Basins
    QI Junyu, CAI Qiangguo, CAI Le, SUN Liying
    2011, 30(1): 95-102. https://doi.org/10.11820/dlkxjz.2011.01.012
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    The study of runoff and sediment reduction benefits of soil and water conservation measures has been improved at different scales separately; however, there are relatively few studies on the scale effect of runoff and sediment reduction benefits of soil and water conservation measures in basins of different scales. In this study for Chabagou, Dalihe and Wudinghe basins, runoff and sediment reduction benefits of soil and water conservation measures in the 1970s are calculated by three methods: rainfall-runoff and rainfall-sediment statistical model (R-RSM), double accumulative curve method (DACM) and time series contrasting method (TSCM) accordingly. As a result, average runoff reduction benefits are 14.47%, 20.22% and 20.78% respectively and average sediment reduction benefits are 64.97%, 43.62% and 47.26% respectively. The results show that there is no scale effect in the results from the three methods when they are applied separately to calculate runoff and sediment reduction benefits in basins of three scales. Runoff reduction efficiency (RRE) and sediment reduction efficiency (SRE) indicating the“efficiency”of the runoff and sediment reduction benefits are introduced, and after analyzing the relationship between runoff reduction efficiency and sediment reduction efficiency of basins of three scales, several conclusions are obtained. (1) Sediment reduction efficiency is always greater than runoff reduction efficiency in basins of three scales, however, the ratio of sediment reduction efficiency to runoff reduction efficiency of small scale basin is greater than that of middle and large scale basins and there is no scale effect of the ratio between middle and large scale basins. (2) Sediment reduction efficiency of small scale basin is lower than that of middle and large scale basins, while runoff reduction efficiency of small scale basin is greater, and runoff reduction efficiency and sediment reduction efficiency of middle and large scale basins are so close that there is no scale effect.
  • Original Articles
    Methods and Uncertainties in Evaluating the Carbon Budgets of Regional Terrestrial Ecosystems
    YU Guirui, WANG Qiufeng, ZHU Xianjin
    2011, 30(1): 103-113. https://doi.org/10.11820/dlkxjz.2011.01.013
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    Quantitative assessment of carbon budgets at regional scale or in different ecosystems is an important scientific issue in the field of ecosystem and global change, which can provide scientific basis for forecasting climate change and regional carbon management serving for mitigation and adaptation to climate change. Though assessment and authentication of regional carbon budgets could not be fulfilled precisely using current measurements and evaluation methods, many progresses had been made. In this paper, we reviewed the observation technique systems, especially the methods and their uncertainties in evaluating regional carbon budget. To evaluate the carbon sink function of ecosystems, main industries, and projects related to carbon sink and their spatiotemporal patterns quantitatively, it is urgent to build an observation and experiment network based on field platforms and to develop a multi-scale observation system comprised by field platforms, terrestrial transects and ecological networks combined with satellites and aviation observations. The system based on observation data, ecological process model, remote sensing model and GIS spatial analysis is also needed to be built. These systems should be under the guideline of multi-scale observation, multi-method confirmation, multi-process fusion, across-scale cognition and simulation. Meanwhile, cycles of carbon, nitrogen and water in terrestrial ecosystems are coupled by various biological processes, while the knowledge of the coupling mechanisms and their influences on the spatiotemporal patterns of carbon source or sink was limited, so it will be an important aspect and new research hot in the research of ecosystem C cycle and regional carbon budget assessment and authentication.
  • Original Articles
    Dendrochemistry Application as a Tool for Biomonitoring Environmental Pollution of Mining Areas
    LEI Mei, GUO Lixin, ZHANG Shanling
    2011, 30(1): 114-120. https://doi.org/10.11820/dlkxjz.2011.01.014
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    The trees, naturally growing in the mining areas, can uptake heavy metals from air, soil, and irrigation water. The pathways of heavy metals entering the trees might be roots, barks, and leaves. After entering the trees, heavy metals will deposit in the tree-rings during cambium development. The long-term fluctuations of element contents in tree rings can be analysed by the laser ablation system coupled to an inductively coupled plasma mass spectrometer. Therefore, the pollution processes of mining areas can be recorded by the variation of heavy metal concentrations in the tree-rings, and the influential ratios of different pollution routes can be semi-quantitatively determined. Cases of applications of dendrochemistry in biomonitoring of air, water and soil pollution were reviewed in this article. Based on the point pollution characteristics of mining areas, the possibility of applying dendrochemistry for pollution monitoring was discussed. Aiming to improve the accuracy of research of atmospheric and soil pollution in mining areas by dendrochemistry, different influential factors of heavy metal concentrations in tree rings, such as tree species, selective uptake of elements by trees, climate variation and nutrient providing, were reviewed. Geostatistics, stable isotope tracer, and synchrotron radiation X-ray fluorescence can improve the accuracy of dendrochemistry for environmental pollution recording. Atmospheric dispersion model predicting ground-level concentrations from a point source of metal emissions, such as smelters, can be calibrated on tree rings in order to reconstruct the spatial and temporal Pb-contamination pattern. Dating of the historical record has been achieved using isotopic analysis, for example 210Pb and 137Cs. With the development of analytical techniques of heavy metals in tree rings, dendrochemistry will play a more important role in pollution monitoring in mining areas. This review highlights the strong potential for dendrochemistry to combine with other approaches in environmental research.
  • Original Articles
    Culture Development and Sea-Level Change during Liangzhu Period
    ZHU Lidong, FENG Yixiong, YEWei, WANG Tianyang, LI Fengquan, LI Lixia
    2011, 30(1): 121-128. https://doi.org/10.11820/dlkxjz.2011.01.015
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    The comparison of archaeological records with that of sea-level changes in the Zhejiang-Shanghai-Jiangsu region shows that there is a close connection between the Liangzhu culture development and sea-level changes during 5.5-4 ka BP. During 5.5-4.9 ka BP, the sea-level of the Zhejiang-Shanghai-Jiangsu area declined by about 3.9 m, providing more space for humankind. Together with warm climate, the space boosted the initial development of Liangzhu culture. The sparse archaeological sites with stilt houses were mostly found on the higher land and the people at that time were engaged in rice planting. During 4.9-4.3 ka BP, the sea level was low and Liangzhu culture was in a period of peak prosperity. The amount of archaeological sites increased significantly, of which the distribution was centralized and in a much larger area. The climate was dry-cool then, and lots of wells were found. People built their houses on land surface. The agriculture and handicraft industries had been developed, and different classes emerged in the society. These indicate that the low sea-level greatly accelerated the prosperity of Liangzhu culture. In 4.3-4 ka BP, the sea level rose again, which reduced the Liangzhu people’s living space, thus relatively narrowed the distribution extent of the culture. In addition, it resulted in fatal floods during the cold event at about 4 ka B.P. People mainly lived in platforms and slope fields. The number of sites was reduced and the environment was worse because of the rising sea-level. As a result, the sea-level changes during 5.3-4.0 ka BP had a significant influence on the Liangzhu culture development.