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  • 2012 Volume 67 Issue 3
    Published: 20 March 2012
      
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  • Spatial Distribution of Major Natural Disasters of China in Historical Period
    LIU Yi, YANG Yu
    2012, 67(3): 291-300. https://doi.org/10.11821/xb201203001
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    Based on collation of historical documents and records of China's major disasters in the historical period, this paper analyzes the characteristics of frequency and distribution of major disasters, including the number of occurrences, the structure and distribution of major disasters, and the number and disttribution of dead people induced by the major disasters. The conclusions can be drawn as follows. (1) Through the analysis of the frequency of major disasters, we found that occurrences of different types of disasters were different and the provincial patterns were significantly different from each other. There is close relationship between different types of disasters and their distribution. (2) Based on the analysis of the disaster losses, the spatial pattern of losses was not the same as that of frequency. The reasons for the above phenomena are as follows. (1) China is one of the countries most affected by natural disasters. The hazard-formative environments and hazard-formative factors of different types of disasters are significantly different. So the natural condition is the decisive factor of the distribution of different major disasters. (2) The losses caused by natural disasters were closely related to the concentration of economic and population. In general, the number of dead people was larger in the areas with more developed agriculture, culture and business.
  • Development of Homogenized Monthly Precipitation Dataset in China during 1900-2009
    LI Qingxiang, PENG Jiadong, SHEN Yan
    2012, 67(3): 301-311. https://doi.org/10.11821/xb201203002
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    Based on the collection and processing of the China's national-wide monthly station observational precipitation data during 1900-2009, the data series for each station has been tested for their homogeneity with Standard Normalized Homogeneity Test (SNHT) method and the inhomogeneous part of the series are adjusted. Then the 1971-2000 climatology normals and precipitation anomalies during 1900-2009 have been transformed into the grid boxes at resolutions of 5白5? and 2白2?, respectively, and two gridded form datasets are constructed by combining the normals and anomalies. After that, the missing values for the 5白5? grid dataset are interpolated by Empirical Orthogonal Function (EOF) techniques. With the datasets at different resolutions, the precipitation change series during 1900-2009 over Chinese Mainland were built, and the annual and seasonal precipitation changing trends for recent 110 years were analyzed. The result indicated that the annual precipitation showed a slightly dryer trend during the 110 years, but with no statistical confidence. To be pointed out, the interpolation of the missing values makes the precipitation amounts in the early 1900s decrease, so the trend for the 110 years increased.
  • Spatio-temporal Probability Behaviors of the Maximum Consecutive Wet Days in Xinjiang, China
    LI Jianfeng, ZHANG Qiang, BAI Yungang, ZHANG Jianghui
    2012, 67(3): 312-320. https://doi.org/10.11821/xb201203003
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    Based on the daily precipitation data from 51 rain stations in Xinjiang during 1960-2005, the spatial and temporal possibility variations of maximum consecutive wet days in the whole year, summer and winter seasons are studied. Nine precipitation extreme indices which reflect the attributes of consecutive maximum wet days are defined, modified Mann-Kendall test is applied to detect the tendencies, and changing rates of indices are evaluated through linear regression with F test. Results show that: (1) two days consecutive wet days occurred most frequently during the year and summer, and the precipitation intensities decreased as the number of days of maximum consecutive wet days increased; in winter, one day consecutive wet days had the maximum possibility, and the intensities increased as the number of days of the maximum consecutive wet days increased; (2) the possibilities of consecutive wet days with short durations reduced, while those of the large number of days increased; the precipitation of consecutive wet days had increasing trends; the intensities of all numbers of days increased; (3) a wet tendency was identified in Xinjiang; wet trend in Southern Xinjiang was more significant than in Northern Xinjiang in summer, while in winter the wet tendency in Northern Xinjiang was more remarkable.
  • Spatial and Temporal Distribution of Dry Spells in China
    LIAO Yaoming, CHEN Deliang, XIE Yun
    2012, 67(3): 321-336. https://doi.org/10.11821/xb201203004
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    Spatial and temporal distribution and trends of dry days, mean and maximum dry spells, the number of long dry spells (longer than 10 days) which are defined according to precipitation daily thresholds of 0.1 mm, 1 mm, 5 mm and 10 mm, are analyzed systematically using historic daily precipitation data from 1951 to 2010 at 672 stations in China. The results show that precipitation daily thresholds of dry days, mean and maximum dry spells with 0.1 mm, 1 mm, 5 mm and 10 mm and the number of long dry spells with 0.1 mm precipitation daily threshold have become longer from Northwest China to Southeast China and those in winter and autumn are longer than those in spring and summer. The spatial and temporal features of these variables are consistent with climate drought of China. The spatial and temporal features of the number of long dry spells with 1 mm, 5 mm and 10 mm daily precipitation thresholds are similar to those of drought disaster occurrence in China. Long dry spells occur frequently in North China, Yellow-Huaihe river basin, Yangtze-Huaihe river basin and areas south of the Yangtze River, and most of them are observed in spring and summer. The trends of dry days, mean and maximum dry spells with 0.1 mm daily precipitation threshold increase in most parts of China, especially in southern China. But the trends of dry days, mean and maximum dry spells with 1 mm, 5 mm and 10 mm daily precipitation thresholds decrease in most of western China, especially in Northwest China.
  • Probabilistic Assessment and Uncertainties Analysis of Climate Change Impacts on Wheat Biomass
    LIU Yujie, TAO Fulu
    2012, 67(3): 337-345. https://doi.org/10.11821/xb201203005
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    Impacts of climate change on agriculture and adaptation are of key concern of scentific research. However, vast uncertainties exist among the global climate models (GCMs)output, emission scenarios, scale transformations, crop model parameteration-simulated outputs. In this study, a probabilistic approach is used to reduce the uncertainties, from 20 climate scenarios output (including four emissions scenarios of A1FI, A2, B1 and B2, and five GCMS of HadCM3, PCM, CGCM2, CSIRO2 and ECHAM4) from the Intergovernmental Panel on Climate Change Data Distribution Centre. We adapt the median values of projected changes in daily mean climate variables for representative stations and drive the CERES (Crop Environment Resource Synthesis)-Wheat model to simulate wheat biomass under baseline condition and global warming scenarios of global mean temperature (GMT) increase of 1 ℃ (GMT+1D), 2 ℃ (GMT+2D) and 3 ℃ (GMT+3D), with and without consideration of CO2 fertilization effects, respectively. Our study results show that elevated CO2 concentration generally compensate for the negative effects of warming temperatures on wheat biomass and the positive effects of elevated CO2 concentration on wheat biomass increase with warming temperatures. There is a high probability of increasing wheat biomass under higher temperature scenarios in consideration for CO2 fertilization effect and rain-fed wheat biomass increase are higher than rain-fed wheat biomass under the same temperature rising scenarios. Due to increase in temperature, projected wheat biomass for GMT + 1D, GMT+2D and GMT+3D would reduce without consideration of CO2 fertilization effects and irrigated wheat biomass would reduce more than rain-fed wheat biomass under the same temperature rising scenarios.
  • Agricultural Landscape Spatial Heterogeneity Analysis and Optimal Scale Selection: An Example Applied to Sanjiang Plain
    WEN Zhaofei, ZHANG Shuqing, BAI Jing, DING Changhong, ZHANG Ce
    2012, 67(3): 346-356. https://doi.org/10.11821/xb201203006
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    Agricultural monitoring requires high temporal frequency data which are currently provided only by moderate spatial resolution sensors. At such moderate spatial resolutions, farmland that is heterogeneous within a pixel will be averaged and hence obscured. This would bias any non-linear estimation of crop growing processes (e.g., net primary productivity (NPP), leaf area index (LAI)). To modify this bias, a first approach is used to explicitly take into account the intra-pixel spatial heterogeneity in the retrieval algorithm. A second approach is to use the surface heterogeneity to disaggregate moderate spatial resolution estimates of land surface variable at a proper scale of spatial variation. Both approaches are required to quantify spatial heterogeneity,and a proper scale selection should be necessary for agricultural monitoring.To this ends, four typical landscape pattern sites in the Jiansanjiang Reclamation Area which is an important basin of commercial grain production in China, were selected and Landsat/TM NDVI image data were analyzed in this study. Based on the variogram analysis, some conclusions can be drawn. (1) Directional experiment variograms analysis can make clear how the human activates and natural factors affect the agricultural spatial heterogeneity qualitatively. For example, dry lands (including the landscape only with dry land and the landscape which is mosaic of dry land and paddy fields in this study) have the largest heterogeneity in North-South direction, while the landscape pattern which only have paddy fields have the largest heterogeneity in East-West direction. Based on this, we can demonstrate that spatial heterogeneity caused by human and natural factors can be examined deeply through variogram analysis. (2) The fitted variograms can present how different landscape patterns have their own spatial heterogeneity quantificationally. In this study, for example, the same type of land use can have lower heterogeneity as different types of land use landscape patterns have larger heterogeneity. (3) Through the variogram analysis of heterogeneity, a method used to select a proper scale (pixel size) for agricultural remote sensing monitoring is discussed.
  • Driving Forces Analysis of Reservoir Wetland Evolution in Beijing Based on Logistic Regression Model
    LI Hong, GONG Zhaoning, ZHAO Wenji, GONG Huili
    2012, 67(3): 357-367. https://doi.org/10.11821/xb201203007
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    The reservoir wetland of Beijing, constitutes one of the important eco-systems in Beijing. The driving factors index system of Beijing reservoir wetland landscape evolution in the study area was built in the two aspects of the natural environment and socio-economy. Natural driving factors include precipitation, temperature, entry water and groundwater depth; social economic driving factors include the resident population, urbanization rate and per capita GDP. Using TM images from 1984 to 2010 to extract reservoir wetland's spatial distribution information of Beijing, we analyzed the area of reservoir wetland change laws in nearly 30 years. The driving mechanism of reservoir wetland evolution in the study area was explored by the Logistic regression model in different periods. The results indicated that in different phases, the driving factors and their influence on reservoir wetland evolution had certain differences. During 1984-1998, the leading driving factors were annual average precipitation and entry water index with the contribution rate of Logistic regression being 5.78 and 3.50, respectively, which was mainly affected by natural environmental factors; from 1998 to 2004, the impact of human activities intensified and man-made reservoir wetland reduced, and the main driving factors were the number of residents, groundwater depth and urbanization rate with the contribution rate of Logistic regression 9.41, 9.18, and 7.77, respectively. During 2004-2010, reservoir wetland evolution was impacted by both natural and socio-economic factors, and the dominant driving factors were urbanization rate and precipitation with the contribution rate of 6.62 and 4.22, respectively.
  • Evolution of Coastline and Subaqueous Geomorphology off the Survived River Mouth in the Yellow River Delta
    PENG Jun, CHEN Shenliang, LI Guqi, LIU Feng, CHEN Guangquan
    2012, 67(3): 368-376. https://doi.org/10.11821/xb201203008
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    Based on the measured data of coastline and bathometry, processed by software of Surfer and Mapinfo, and in combination with sediment load in different phases at Lijin gauging station, evolution of coastline and subaqueous geomorphology off the survived river mouth in the Yellow River delta is analyzed. The results show that ~68% of the sediment delivered by the Yellow River to the sea deposited in the river mouth and littoral area from 1953 to 2000. The changes of coastline in different coasts had a distinctive characteristic in response to transfers of river course into the sea. The coastline was stable in the coasts west of Diaokou river mouth. The coastline from the east of Diaokou river mouth to the north of Gudong oilfield had experienced siltation, and then serious erosion, finally kept stability with the conservation of sea walls. In general, the coastline at the survived river mouth of Qingshuigou river course stretched seaward, whereas the south side of sand spit at Qingshuigou old river mouth eroded after the Yellow River inpouring into the sea near the position at Qing 8. The subaqueous geomorphology off the survived river mouth exhibited siltation from 1976 to 1996, with flat topset beds and steeper foreset beds. From 1996 to 2005, the subaqueous geomorphology off the Qingshuigou old river mouth experienced erosion in the topset and foreset beds, but siltation in the bottomset beds.
  • Monitoring Change and Position of Coastlines from Satellite Images Using Slope Correction in a Tidal Flat: A Case Study in the Yellow River Delta
    LIU Yanxia, HUANG Haijun, QIU Zhongfeng, CHEN Jitao, YANG Xiguang
    2012, 67(3): 377-387. https://doi.org/10.11821/xb201203009
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    Tidal and landform variations have a significant impact on detection of coastline changes in a tidal flat environment. This paper presents a slope correction method of determining 1985 national height datum shoreline positions from two satellite images that take into account tidal variations. Furthermore, volumes of tidal flats are calculated by tidal flat gradient. Combination of remote sensing images, the measured cross-section data and depth measurement data analysis showed that although the inter-tidal range of the image has a greater impact on gradient estimates, estimation of tidal gradient is feasible by choosing appropriate images. The minimum error of consistency check is up to about 0.2% of estimate gradient, and root mean square error of absolute check is less than the measured gradient in an order of magnitude. Muddy-silt tidal flats were used to test this method in the south coastal area of the Yellow River Delta. Multitemporal remote sensing data of Landsat MSS and TM/ETM from 1973 to 2009, totaling 14 years, were used to examine the changing pattern of erosion and accretion of the tidal flat from Tianshuigou to Xiaoqing River estuary. Since the diversion of the Yellow River in 1976, the sediment of the river is deposited directly about 3 km from Tianshuigou southward in the study area. The maximum accretion occurs near the Tianshuigou where the coastline advanced seaward over 0.7 km with a mean net accretion rate of 31 m/a. During the period 1989-2002, rapid sedimentation happened in the southern part of the study area. Accumulation of sediment and resuspended sediment from the Yellow River is the major driving force. From 1973 to 2009, the general tendency of coastline was erosive with a mean net rate of 51 m/a. The enhanced ocean dynamics caused by the diversion of the Yellow River is the main reason. It is indicated that the volume of tidal flats is reasonable and reliable for detecting shoreline change.
  • Contributions of Precipitation and Human Activities to the Runoff Change of the Huangfuchuan Drainage Basin: Application of Comparative Method of the Slope Changing Ratio of Cumulative Quantity
    WANG Suiji, YAN Yunxia, YAN Ming, ZHAO Xiaokun
    2012, 67(3): 388-397. https://doi.org/10.11821/xb201203010
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    The runoff of some rivers in the world especially in the arid and semi-arid regions has decreased remarkably with global or regional climate change and intensive human activities. The runoff decrease in the arid and semi-arid areas of northern China has brought severe problems in livelihood and ecology. So, to reveal the changing characteristics, trends of runoff and their influencing factors have been an important scientific problem for drainage basin management. This study, taking the Huangfuchuan drainage basin as an example, analyzes the changing trends of the runoff and precipitation according to the measured data in 1960-2008. Two inflection points, 1979 and 1998, for the accumulative runoff, and one inflection point, 1979, for the accumulative precipitation, were identified according to the methods of accumulative anomaly analysis. The linear relationships between year and accumulative runoff in 1960-1979, 1980-1997 and 1998-2008 and between year and accumulative precipitation in 1960-1979 and 1980-2008 were fitted. Adopting the new method put forward in this study, we made a comparison of slope change ratio of the fitted beeline between year and accumulative quantity, and taking 1960-1979 as the base period, we obtained the contribution rates of the precipitation and human activities to the decreased runoff, which were 36.43% and 63.57% in 1980-1997, and 16.81% and 83.19% in 1998-2008, respectively. This study revealed the changing trend of runoff of the Huangfuchuan drainage basin during 1960-2008 and calculated the contribution ratio of the main influencing factors. It plays an important role in the drainage basin management in arid and semi-arid areas. Contemporarily, the new method of quantitative research can be applied in the quantitative evaluation of runoff change in the river basin of arid and semi-arid areas.
  • Temporal and Spatial Variations and Statistical Models of Extreme Runoff in Huaihe River Basin
    DU Hong, XIA Jun, ZENG Sidong, SHE Dunxian, ZHANG Yongyong, YAN Ziqi
    2012, 67(3): 398-409. https://doi.org/10.11821/xb201203011
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    Based on the daily runoff data from 20 hydrological stations during 1956-2010 above the Bengbu Sluice in the Huaihe River Basin, run test, trend test and Mann-Kendall test are used to analyze the variation trend of annual maximum runoff series. The annual maximum series (AM) and peaks over threshold series (POT) are selected to describe the extreme distributions of GEV and GPD. Temporal and spatial variations of extreme runoff in the Huaihe River Basin are analyzed. The results show that during the period 1956-2010 in the Huaihe River Basin, annual maximum runoff at 10 stations have a negative trend, while the other 10 stations have a positive trend which is not significant. The maximum runoff event almost occurred in the flood period during the 1960s and 1970s. The extreme runoff events in the Huaihe River Basin mainly occured in the mainstream of the Huaihe River, Huainan mountain areas, and Funiu mountain areas. Through Kolmogorov-Smirnov test, GEV and GPD distributions can be well fitted with AM and POT series respectively.
  • Water Resources Supporting Capacity to Regional Socio-economic Development of China
    LI Jiuyi, LI Lijuan
    2012, 67(3): 410-419. https://doi.org/10.11821/xb201203012
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    An indicator called Water Supporting Index (WSPI) was built to measure the degree of water scarcity, which considered water resources and water withdrawal of both local and upstream areas. An evaluation model was established to calculate WSPI of 210 sub-basins and also in province scale and county scale. Water resources supporting capacity classes to regional socio-economic development was divided by WSPI. The spatial status of the capacity classes and its relationship with population and Gross Domestic Product were analyzed. Furthermore, the differences in regions suffering water scarcity were discussed. The result of WSPI was very similar to the actual water scarcity situation of China. Therefore, WSPI can be used in water resources management and socio-economic development decision-making.
  • Identification of China's Suitable Regions for Rural Residential Land Consolidation Based on Livelihoods Transformation
    CHEN Yangfen, LIU Yansui, YANG Ren
    2012, 67(3): 420-427. https://doi.org/10.11821/xb201203013
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    This paper deconstructs the theoretical relationship of non-agricultural ratio and per rural residential land area, which represent livelihoods transformation and rural land use respectively. Then it quantitatively analyzes the inflection point value of livelihoods transformation and identifies the corresponding suitable rural residential land consolidation regions based on the GIS technique and spatial autocorrelation analysis. The results indicate that there exists an inverted U-shaped relationship between non-agricultural ratio and per rural residential land area. By controlling the main influential factors such as resource endowment, economic development stage, the terrain, the urbanization ratio, the inflection point value of non-agricultural ratio is 38.36%. According to this inflection point value and the standards (150 m2 per capita) prescribed by the State for rural residential land use, four rural residential land consolidation regions with descending suitability are identified, including the prior consolidation region, the optimal consolidation region, the moderate potential region, and the restricted consolidation region. For prior consolidation region which enjoys the highest suitability, its suitable consolidation model is the urbanization leading model, and it is distributed mainly in north, east and central China. Peasants in the optimal consolidation region, mainly in southeast and southwest China, have a relatively low dependence on agriculture production, but rural land use here has been intensive. Rural residential land consolidation here is therefore suggested to integrate with central village construction. In the moderate potential region which is mainly located in the vast northern China, it has the highest per rural residential land area, but its non-agricultural ratio is too low to support massive rural land consolidation, it thus suits for the consolidation model of intra-village intensification. The restricted consolidation region, located mainly in southwest China, should pay more attention to its ecological environment and ecological function rather than land potential. Restricted rural residential land consolidation is suggested to combine with large-scale projects such as ecological immigrant project.