Table of Content

20 May 2011, Volume 66 Issue 5 Previous Issue    Next Issue

Temporal and Spatial Change Analysis of the Sensitivity of Potential Evapotranspiration to Meteorological Influencing Factors in China LIU Changming, ZHANG Dan 2011, 66 (5):  579-588.  doi: 10.11821/xb201105001 Abstract ( )   PDF (1091KB) ( )   Save Potential evapotranspiration (E0), as an estimate of the evaporative demand of the atmosphere, has been widely discussed in researches on irrigation management, crop water demand and predictions in ungauged basins (PUBs). Analysis of the sensitivity of E0 to meteorological factors is the basic research on the impact of climate change on water resources, and also is important to the optimal allocation of agricultural water resources. In this study, the calculation method of global radiation in Penman-Monteith formula was improved by optimazation, and the sensitivities of Penman-Monteith potential evapotranspiration to the daily maximum temperature (STmax), daily minimum temperature (STmin), wind speed (SU2), global radiation (SRs) and vapor pressure (SVP) were calculated and analyzed based on the long-term meteorological data at 653 meteorological stations in China during the period 1961-2000. The results are obtained as follows. (1) The multiple correlation coefficient between E0 and pan evaporation increased from 0.61 to 0.75 using the improved Penman-Monteith formula. Trend analysis shows that E0 had the decreasing trends in eight basins of China, which indicates that "pan evaporation paradox" common existed in China from 1960 to 2007. (2) Spatially, Tmax was the most sensitive variable in the Haihe River, Yellow River, Huaihe River, Yangtze River, Pearl River and river basins in southeastern China, and VP was the most sensitive variable in the Songhua River Basin, Liaohe River Basin and river basins in Northwest China, while Rs was the most sensitive variable in river basins of Southwest China. For the national average, the most sensitive variable was VP, followed by Tmax, Rs, U2 and Tmin. In addition, the changes in sensitivity coefficients had certain correlation with elevation. (3) Temporally, the maximum values of STmax and SRs occurred in July, while the maximum values of STmin, SVP and SU2 occurred in January. Moreover, trend analysis indicates that STmax had decreasing trends, while STmin, SU2, SRs and SVP had increasing trends. References | Related Articles | Metrics

Patterns of Evapotranspiration and GPP and Their Responses to Climate Variations over the North China Plain MO Xingguo, LIU Suxia, LIN Zhonghui, QIU Jianxiu 2011, 66 (5):  589-598.  doi: 10.11821/xb201105002 Abstract ( )   PDF (1222KB) ( )   Save Insufficient water resources is a major constraint on sustainable development of agriculture and socio-economy, and an imminent threat to national food security. Present situation attached particular importance to assurance of water supply for agriculture and ecology, which was on the basis of effective predication for regional evapotranspiration and water use efficiency (WUE). In this paper, an evapotranspiration and gross primary production (GPP) model based on vegetation index from Terra-MODIS was developed, and evapotranspiration and GPP in the North China Plain (NCP) during the period 2000-2009 were simulated. Results indicated that longitudinal trend was noticeable for both evapotranspiration and GPP distribution, especially in winter wheat growing season. With respect to water balance, it is concluded that regions with higher evapotranspiration than precipitation were mainly distributed to the north of the Yellow River, while the southern NCP showed a rainfall surplus. Affected and regulated by both climatic fluctuation and dynamic response of vegetation, both evapotranspiration and GPP illustrated considerable inter-annual variation. The research results can provide guidance to assessment of water consumption for ecological environment and water use efficacy. References | Related Articles | Metrics

Temporal and Spatial Patterns of Droughts for Recent 50 Years in Jiangsu Based on Meteorological Drought Composite Index BAO Yunxuan, MENG Cuili, SHEN Shuanghe, QIU Xinfa, GAO Ping, LIU Cong 2011, 66 (5):  599-608.  doi: 10.11821/xb201105003 Abstract ( )   PDF (1093KB) ( )   Save In this paper, the observed meteorological data of 54 meteorological stations from 1960 to 2009 in Jiangsu Province of China were collected and a composite index (CI) of meteorological drought was used to analyze the temporal and spatial characteristics of droughts in the province. Based on the daily CI values of each station in the 50 years, the drought processes of each station were confirmed one by one and the occurrence frequencies, scopes and severities of the meteorological droughts were computed and analyzed to reveal the temporal and spatial occurrence pattern of the meteorological droughts in different parts of Jiangsu Province. The results were showed as follows. (1) The annual and seasonal occurrence frequencies of the meteorological drought in the province decreased from north to south. In all the seasons, the occurrence frequency of the winter droughts was the highest. (2) The years of drought occurrence in a large scope (more than 90% of the total area of the province) were most in winter and least in summer. (3) In the 50 years, there was a notable inter-annual wave of the annual average lasting days and the annual average occurrence severities of meteorological droughts in the whole province but their linear changing tendencies were not obvious. (4) The drought lasting days of different grades in Jiangsu reduced from north to south in general. The drought lasting days of different grades were most in winter and least in summer. References | Related Articles | Metrics

Changes in Hydrological Interactions of the Yangtze River and the Poyang Lake in China during 1957-2008 GUO Hua, HU Qi, ZHANG Qi 2011, 66 (5):  609-618.  doi: 10.11821/xb201105004 Abstract ( )   PDF (616KB) ( )   Save Interaction of the Yangtze River and the Poyang Lake strongly affects the Poyang Lake water resources and flood and drought potentials in the lake basin. This interaction and its variation are examined in this study for the period 1957-2008. In addition, changes in the relationship between the Yangtze River and Poyang Lake after the operation of the Three-Gorge Dam (TGD) are evaluated using the TGD operation data available for 2004-2006. Major findings are shown as follows. 1) At interannual to decadal timescales the variation in the Poyang Lake water level is primarily determined by fluctuations of the climate and the inflow from the five major tributaries in the lake basin. By influencing the lake level these fluctuations also affect the lake-river interaction. 2) At the seasonal timescale, the Poyang Lake has the largest outflow to the Yangtze River and exerts a strong pressure on the mainstream during April-June, when the lake receives annual peak inflow from its tributaries. The Yangtze River's blocking and/or reversed flow to the Poyang Lake are the strongest during July-September. 3) The operation of the TGD has changed little in terms of seasonal variations of these lake and river forcings. In most of the seasons, the influence of the TGD has resulted in less than 10% of the variation in the Yangtze River flow. However, by damming or releasing water, the TGD can result in seasonal changes in the Yangtze River flow and river-lake interactions. These subtle effects from the TGD operation are quantified and compared to the climate effect on the river-lake interactions. These comparisons show enhancement in some seasons while weakening in the other seasons of the climate effect on river-lake interactions and flood or drought potential in the lake basin by the TGD operation. References | Related Articles | Metrics

Precipitation Variation and Its Impacts in Sichuan in the Last 50 Years ZHOU Changyan, CEN Sixuan, LI Yueqing, PENG Guozhao, YANG Shuqun, PENG Jun 2011, 66 (5):  619-630.  doi: 10.11821/xb201105005 Abstract ( )   PDF (1025KB) ( )   Save Based on the daily precipitation data of 133 stations in Sichuan from 1961 to 2008, precipitation variation and its impacts are analyzed in this paper. Results indicate that during 1961-2008, the spatial distribution of the annual precipitation variation in Sichuan shows an increase-decrease-increase situation from west to east: increase in most parts of Ganzi and Liangshan, decrease in Aba and most parts of Sichuan Basin and increase in the northeastern part of the basin. The linear trend coefficient field in the spatial changes of the rainstorm days also displays an increase-decrease-increase situation from west to east: increase in most parts of Ganzi, Liangshan and Panzhihua, remarkable decrease in the western and central parts of the basin and significant increase in the northeastern part of the basin. Apart from some parts of the central and southern basin, the rainstorm intensity in the province tended to increase, and the trend in the northeastern part of the basin was notable. . The variation trend of the heavy rain days is close to that of the rainstorm, showing an increase-decrease-increase change from west to east. Except for some parts of Ganzi, the number of moderate and light rain days in most parts of Sichuan decreased. On the contrary, the number of days without rain increased greatly in most parts of the province, except for part of western Sichuan Plateau. References | Related Articles | Metrics

RS and GIS-based Assessment for Eco-environmental Sensitivity of the Three Gorges Reservoir Area of Chongqing LIU Chunxia, LI Yuechen, YANG Hua, MIN Jie, WANG Caijun, ZHANG Hong 2011, 66 (5):  631-642.  doi: 10.11821/xb201105006 Abstract ( )   PDF (792KB) ( )   Save Four factors (soil erosion, rocky desertification, bio-inhabitation and acid deposition) are selected to establish the evaluation model of eco-environmental sensitivity by using the integrated approach of GIS and RS in the present study. This paper conducts an integrated research on the eco-environmental sensitivity and reveals its spatial features in a quantitative way. The results are shown as follows. (1) The strong, moderate and extreme sensitivities are the main types of soil erosion sensitivity. The northeastern part of the study area is the most sensitive area of soil erosion sensitivity. The proposed soil erosion sensitivities were found to be consistent with real soil erosion. (2) The proportion of insensitivity area dominates karst rocky desertification, followed by strong and moderate sensitivity. The northeastern and southern parts of the study area are the most sensitive area and the western-central part is not sensitive. The real karst rocky desertification accorded with karst rocky desertification sensitivity. (3) The insensitivity and strong sensitivity are the main types of the sensitivity of bio-inhabitation. The northeastern and southern parts of the study area are the most sensitive area. The bio-inhabitation sensitivities in the central and western parts of the study area are relatively low. (4) The area of strong sensitivity of acid deposition is the biggest, followed by moderate and slight sensitivities. The extremely sensitive areas spread fragmentarily. The moderate and strong sensitive areas are concentrated and present a massive distribution. The slight sensitive and insensitive areas of acid deposition are distributed along the rivers and streams in a belt-shaped pattern. (5) The slight sensitivity of integrated eco-environment sensitivity is the main type in the study area, the insensitivity and moderate sensitivity take a second place. The integrated eco-environment sensitivity in the northeastern and southern parts of the study area is high. The integrated eco-environment sensitivity in the central and western parts of the study area is low. References | Related Articles | Metrics

Maize Drought Disaster Risk Assessment Based on EPIC Model: A Case Study of Maize Region in Northern China JIA Huicong, WANG Jing'ai, PAN Donghua, CAO Chunxiang 2011, 66 (5):  643-652.  doi: 10.11821/xb201105007 Abstract ( )   PDF (903KB) ( )   Save As the global climate change and food security became an increasingly important issue, agriculture drought comes to the focus of attention. China is a typical monsoon climate country as well as an agricultural country with the world's largest population. The East Asian monsoon has had a tremendous impact on agricultural production. Therefore, a maize drought disaster risk assessment, in line with the requirements of sustainable development of agriculture, is important to drought disaster reduction and food security. This study collected information on meteorology, soil, land use and agro-meteorological observation of the research area, and quantitative assessment was done to present spatio-temporal distribution of maize drought in maize region of northern China based on the concept framework of "Hazard-inducing factors assessment (Hazard)-Vulnerability assessment of hazard-affected body (Vulnerability Curve)-Risk assessment (Risk)", importing crop model EPIC (Erosion Productivity Impact Calculator), and using crop model simulation and digital mapping techniques, from the point of view of whole growth period and sub-growth period. The results showed that in terms of 2-, 5-, 10- and 20-year return periods, the overall maize drought risk decreased gradually from northwest to southeast in the maize planting areas. In the 20-year return period, high risk value regions (maize risk level ≥ 0.5) are concentrated in northern Hebei plateau and central and southern parts of Shandong Province, accounting for 7.63% of the total maize area. The high risk maize growing periods of maize region in northern China were heading - tasseling period, tasseling - milking period and milking - mature period, which should be paid more attention. This paper may provide theoretical basis and technological support for maize drought risk prevention and mitigation of high-risk areas and high-risk periods. References | Related Articles | Metrics

Assessment of Desertification Using Time Series Analysis of Hyper-temporal Vegetation Indicator in Inner Mongolia YIN He, LI Zhengguo, WANG Yanglin, CAI Fu 2011, 66 (5):  653-661.  doi: 10.11821/xb201105008 Abstract ( )   PDF (826KB) ( )   Save Desertification is one of the serious threats to the environment in arid and semi-arid northern China. In order to understand inter-annual vegetation dynamics, vegetation indicators have been widely used in desertification assessment. In this study, rain use efficiency (RUE) derived from hyper-temporal remote sensing images has been used for desertification assessment. Based on time-series analysis, this study focused on how the desertification developed in Inner Mongolia and how the desertification reversed in the extremely arid environment. Results showed that during the past 11 years, there was no significant desertification development in Inner Mongolia. Parts of area showed a significant increase trend of RUE, especially in the eastern part of Ordos Plateau and southern Daqing Mountain, as well as the region from the Greater Hinggan Mountains to northern Yanshan Mountains. It is indicated that the ecological conditions in these areas have tended to be much better than before. The reason may be that the vegetation protection policies adopted in northern China have exerted a positive effect on the local environment. The results also showed that there was a significant relationship between rainfall and vegetation restoration, areas with more precipitation tend to be more easily restored, especially in the areas with more 300 mm precipitation. In addition, the research on desertification reversion showed that the desert edge region in western Inner Mongolia have changed intensively, and desertification reverse assessment needs to be further examined. References | Related Articles | Metrics

Water Chemistry of the Lakes and Groundwater in the Badain Jaran Desert SHAO Tianjie, ZHAO Jingbo, DONG Zhibo 2011, 66 (5):  662-672.  doi: 10.11821/xb201105009 Abstract ( )   PDF (948KB) ( )   Save Based on the analysis of ion chemical composition of lake water and shallow groundwater in the Badan Jaran Desert, this paper discussed the characteristics of chemical composition, type of the lake water, spatial variation of lake water, and possible supply sources of lake water and groundwater in the desert areas. The results show that the pH, salinity, TDS and electrical conductivity of the lakes are greater than those of groundwater. The ion contents of the water samples are dominated by Na+ and Cl-. Most of the higher salinity lakes are Na(K)-Cl-(SO4) type, and a few low-salinity lakes are Na-(Mg)-(Ca)-Cl-(SO4)-(HCO3) type. Most of the groundwater bodies are Na-(Ca)-(Mg)-Cl-(SO4)-(HCO3) type, attribute brackish lake, and only a few present a Na-Cl-SO4 type, flowing under salt water lake. The pH, salinity, TDS and electrical conductivity of the southeastern lakes are relatively low, and there are slightly alkaline lakes, while the pH value, salinity, TDS and electrical conductivity of water in the northern lakes are much greater than those of the southeastern lakes, so the northern lakes are mederately alkaline and salt water ones. In the southeastern part of the Badan Jaran Desert, the chemical characteristics of ions of the lakes water show a changing trend from south to north in the order of brackish lake→salt water lake→Salina. The changing trends of chemical compositions of ions in recent 9 years indicate that most of the ion contents have a shade of reduced in Boritaolegai, east Badain, west Badain, Nuoertu and Huhejilin Lake, which states clearly that the amount of fresh water is increasing in the 9-year period. The chemical compositions of the lake water reveal that the flow direction of lake water is from the southeast to northwest in the Badan Jaran Desert. References | Related Articles | Metrics

Review on Sustainable Utilization of Salt-affected Land WANG Jiali, HUANG Xianjin, ZHONG Taiyang, CHEN Zhigang 2011, 66 (5):  673-684.  doi: 10.11821/xb201105010 Abstract ( )   PDF (619KB) ( )   Save The exploitation of salt-affected land resources has made significant contribution to grain production. However it will be faced with a big challenge due to fresh water shortage and climate change. In the past few years, great progress has been made in sustainable utilization of salt-affected land. The contents of this paper include the following parts: (1) the major progress of Technology Research and Development (Tech R&D), drainage waters disposed off in an environmentally safe manner, and necessary management for technology of sustainable use of salt-affected land; (2) a detailed review of farm household behavior of technology choice for sustainable salt-affected land; (3) a brief review of the scientific research method for sustainable use of saline land. It is suggested that the following aspects should be further studied: (1) to strengthen the cooperation of scientists in different disciplines; (2) to emphasize the research on micro-subject farm household behavior of technology choice; (3) to increase the scientificity of research method. References | Related Articles | Metrics

Deposition Evidences of the 4 ka BP Flood Events in Central China Plains ZHANG Junna, XIA Zhengkai 2011, 66 (5):  685-697.  doi: 10.11821/xb201105011 Abstract ( )   PDF (955KB) ( )   Save Evidences from archaeological and Quaternary geological researches have proved that the prehistoric flood events occurred frequently around 4000 a BP. The flood events' characteristic, scale, cause and their influence on human cultural evolution have been a concern to researchers. In China, the research on prehistoric flood around 4000 a BP started in the 1990s. In the following 10 years, geologic and archaeological relics were gradually found in Lajia Site of Qinghai Province, Xinzhai Site of Henan Province, Cuoli Site of Henan Province, Mengxian Site of Henan Province, Yinjiacheng Site of Shandong Province, etc., which aroused attention at home and abroad. The Central China Plains, the birthplace of Chinese civilization, have a few 4000 a BP flood relic sites, however, the number is small and much work should be done. Based on the previous researches and latest archaeological excavations, we carried out a study on 4000 a BP flood events in the Central China Plains, and found many geologic and archaeological relics sites, of which the most representative were the Erlitou Site of Luoyang, western Henan Province, the Xijincheng Site of Jiaozuo, northern Henan Province, and the Zhoujiazhuang Site of Jiangxian, southern Shanxi Province. These sites are situated on different types of landforms. Our research shows that all the three prehistoric flood events were related to humid climate. Meanwhile, due to different geomorphic conditions, the flood processes were different, and their influences on human beings were different, too. Our research extends the distribution area of flood relics, helps people to know more about the 4000 a BP extreme flood events, and provides abundant materials for further discussion on the environmental background of the origin of Chinese civilization. References | Related Articles | Metrics

New Findings and Dating of Lacustrine Sediments in the Xishanzui Subuplift, Hetao Basin FAN Tianlai, FAN Yuxin, WEI Guoxiao 2011, 66 (5):  698-708.  doi: 10.11821/xb201105012 Abstract ( )   PDF (1069KB) ( )   Save A complete sedimentary profile composed mainly of typical lacustrine sediments including beachrock and cut-and-built platform located in the Xishanzui subuplift, Hetao Basin, has been found. The geomorphological and stratigraphic evidence indicates that there was a paleolake with its highest lake up to 1080 m a.s.l. Stratigraphic analysis of the profile indicates that this subuplift experienced an environmental change from a deep lake to a shallow lake and then to non-lake environment (suggested by alluvial/diluvial sediments). Optical dating results support that Xishanzui subuplift was actually covered by a deep water lake, potentially the Megalake "Jilantai-Hetao" at around 65 ka BP when the lake reached its highest level. And no lake level has exceeded the highest level inferred from sedimentary sequence in the profile. References | Related Articles | Metrics

Evaluating Methods and Scale Effects of Attribute Information Loss in Rasterization: A Case Study of 1:250 000 Land Cover Data of Sichuan BAI Yan, LIAO Shunbao, SUN Jiulin 2011, 66 (5):  709-717.  doi: 10.11821/xb201105013 Abstract ( )   PDF (713KB) ( )   Save Taking land cover data of Sichuan at the scale of 1:250,000 in 2005 as a case study, this paper selects 16 spatial scales from 600 m to 30 km, uses rasterizing method based on the Rule of Maximum Area (RMA) in ArcGIS and two evaluation methods of attribute accuracy loss, which are Normal Analysis Method (NAM) and a new Method Based on Grid Cell (MBGC), respectively, and analyzes the scale effect of attribute (area) accuracy loss at 16 different scales by the two evaluating methods comparatively. The results are shown as follows. (1) At the same scale, mean attribute accuracy loss computed by Method Based on Grid Cell are significantly bigger than that computed using Normal Analysis Method. Moreover, this discrepancy is ranged between 1 km and 10 km, while the grid cell is larger than 10 km. Mean attribute accuracy loss computed by these two evaluation methods is stable, even tended to be parallel. (2) Method Based on Grid Cell can not only estimate RMA rasterization attribute accuracy loss accurately, but can express the spatial distribution of rasterization attribute loss objectively. (3) The suitable scale domain for RMA rasterization of land cover data of Sichuan at the scale of 1: 250,000 in 2005 is better, equal or less than 800 m, in which the data volume is favorable, and the attribute accuracy loss is less than 2.5%. References | Related Articles | Metrics