CHARACTERISTICS OF VEGETATION COVER,ROUGHNESS AND ALBEDO DISTRIBUTION OVER CHINA

To build land surface dataset for climate model,with application of remote sensing techniqueas well as the Geographic Information System(GIS),the data of surface type,roughness andalbedo over China in 1997 were retrieved,resolutions being 10 km×10 km.Based on these data,an analysis is conducted on the geographic distributions and seasonal variations of surfacevegetation cover and roughness as well as albedo over China.Results show that surface vegetationcover is mainly located to the south of Yangtze River,in Southwest and Northeast China andsparse vegetation cover is in the Northwest.The variation of land surface cover affects thevariations of land surface roughness and albedo.High albedo occurred in the north of XinjiangAutonomous Region,the north of Northeast China and the Qinghai-Xizang Plateau in winter,incorrespondence with the location of snow cover.For most part of China,surface roughness decreases and albedo increases in winter,while theroughness increases and the albedo decreases in summer,which could mainly result from landsurface cover(snow cover and vegetation cover)and soil moisture changes.This shows that thegeographic distribution and seasonal variation of the albedo are almost opposite to those of theroughness,in agreement with theoretical results.Temporally,the amplitude of surface roughnesschange is quite small in comparison with the roughness itself.     

基于R树索引的三维场景细节层次自适应控制方法

针对大规模三维城市建模需要,介绍一种基于三维R树索引的多细节层次（简称LOD）管理方法,从叶节点层向根节点自动生成LOD场景,并设计实现LOD检索的算法。通过试验分析,证明本文的LOD定义参数能够定量控制三维场景中的渲染目标数目,进而实现三维场景的自适应可视化方法,尤其适合于建筑物和树木类型的地物目标。     

基于SICAD／Open空间拓扑结构的地籍空间实体图形变更处理

简要介绍了一种GIS平台SICAD/Open，详细描述了SICAD/Open空间拓扑结构，给出了基于SICAD/Open空间拓扑结构的地籍空间实体图形变更处理方法，为在地籍信息系统中利用地理信息系统技术实现地籍空间实体图形变更提供了一种切实可行的操作方法。文中描述的处理方法已成功应用于上海市地籍管理信息系统中。     

Acquisition of Directional Parameters in Aerial Images Based on DEM Data

1　Extraction of the steep curve mapThe steep curve is defined as connection linefrom zero cross points which are produced fromthe convolution of Laplace ( LOG) filtration toDEM. Firstly, the elevation data from DEM areprocessed with LOG convolution and zero cross.The sampling formula is 2G(i,j) =12πσ6(r2 -2σ2)e-r2/2σ2 (1)where -M≤i≤M,-M≤j≤M,r2=i2+j2; M isthe filtration radius, nearly equaling to 5.1σ2; pre diction errorσis set to 4. Suppose that e[i,j] is asmall …     

Synthesis of accelerations of the 1976 Tangshan earthquake(M_S 7.8)in near-and far-field by using semi-empirical method

Ｓｙｎｔｈｅｓｉｓｏｆａｃｃｅｌｅｒａｔｉｏｎｓｏｆｔｈｅ１９７６Ｔａｎｇｓｈａｎｅａｒｔｈｑｕａｋｅ（ＭＳ７．８）ｉｎｎｅａｒａｎｄｆａｒｆｉｅｌｄｂｙｕｓｉｎｇｓｅｍｉｅｍｐｉｒｉｃａｌｍｅｔｈｏｄＱＩＦＥＮＧＬＵＯ１）（罗奇峰）ＹＵ?..     

StudyofCurieisothermalsurfaceinSichuanBasinandtheseismicareaonitswesternmar┐gin

ＳｔｕｄｙｏｆＣｕｒｉｅｉｓｏｔｈｅｒｍａｌｓｕｒｆａｃｅｉｎＳｉｃｈｕａｎＢａｓｉｎａｎｄｔｈｅｓｅｉｓｍｉｃａｒｅａｏｎｉｔｓｗｅｓｔｅｒｎｍａｒ┐ｇｉｎＸＩＡＮＺＨＡＮＧ（张先），ＸＩ－ＦＥＮＧＨＵ（虎喜凤），ＪＩＮＧ－ＸＩＵＳＨＥＮ（沈京秀...     

Study on the characteristics of crust－mantle transition zone in Western Yunnan Province

Ｓｔｕｄｙｏｎｔｈｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｃｒｕｓｔ┐ｍａｎｔｌｅｔｒａｎｓｉｔｉｏｎｚｏｎｅｉｎＷｅｓｔｅｒｎＹｕｎｎａｎＰｒｏｖｉｎｃｅＨＯＮＧ－ＸＩＡＮＧＨＵ（胡鸿翔）ＺＨＯＮＧ－ＹＡＮＧＬＩＮ（林中洋）ＹＩＮ－ＪＵＢＩＡＮ（边银...     

Research on seismic intensity zonation by use of the response intensity of historical earth－quakes───with the central part of Shanxi Province as an example

Ｒｅｓｅａｒｃｈｏｎｓｅｉｓｍｉｃｉｎｔｅｎｓｉｔｙｚｏｎａｔｉｏｎｂｙｕｓｅｏｆｔｈｅｒｅｓｐｏｎｓｅｉｎｔｅｎｓｉｔｙｏｆｈｉｓｔｏｒｉｃａｌｅａｒｔｈ┐ｑｕａｋｅｓｗｉｔｈｔｈｅｃｅｎｔｒａｌｐａｒｔｏｆＳｈａｎｘｉＰｒｏｖｉｎｃｅａｓａｎｅｘ...     

Temporal variation of suspended sediment load in the Pearl River due to human activities

Data on sediment flux at three hydrologic stations from the 1950s to 2006 are utilized to study the decadal,annual,and monthly variations in suspended sediment load delivered from the Pearl River to the ocean.Results show that variations in sediment flux from three main tributaries,including the West River,the North River and the East River,are spatially non-uniform.Since nearly 90%of the suspended sediment load comes from the West River,its variation has dominated the overall tendency of sediment flux in the entire Pearl River.Although a significant decreasing trend exists in the annual variation of the total sediment flux,the decadal change can be divided into an increasing phase and a decreasing phase,with the turning point between the two phases in the late 1980s.From the 1950s to the 1980s,the average annual river sediment flux increased by 30.43%.However,sediment flux has decreased significantly since the 1990s,with the average sediment flux being 38.60%less in the 2000s than that in the 1950s.The current sediment flux is also 52.93%less than its peak in the 1980s. The monthly variation pattern of the suspended sediment load transport to the sea is more interesting. For the West River,all months show a decreasing trend,and for most months the reduction values are significant.However,for the East River the sediment load shows a decrease trend in the dry season and an increase trend in the wet season.The method of regression analysis was used to study the influence of precipitation in the variation on the sediment flux.It was found that the climate change is not the main driving force behind the variation in suspended sediment load.Before the 1990s, intensive land use destroyed the vulnerable ecosystem of the upper Pearl River,and speeded up the process of rocky desertification.Consequently,aggravated soil erosion caused an increase in suspended sediment load.However,sediment retention within reservoirs had begun to play a dominant role after the massive construction of large dams after 1990,and resulted in a decrease in the suspended sediment load delivered to the ocean.     

SWAT-based runoff and sediment simulation in a small watershed,the loessial hilly-gullied region of China:capabilities and challenges

Model calibration and validation are necessary before applying it for scenario assessment and watershed management.This study presented the methodology of evaluating Soil and Water Assessment Tool(SWAT) and tested the feasibility of SWAT on runoff and sediment load simulation in the Zhifanggou watershed located in hilly-gullied region of China.Daily runoff and sediment event data from 1998-2008 were used in this study;data from 1998-2003 were used for calibration and 2004-2008 for validation.The evaluation statistics for the daily runoff simulation showed that the model results were acceptable,but the model underestimated the runoff for high-flow events.For sediment load simulation,the SWAT performed well in capturing the trend of sediment load,while the model tended to underestimate sediment load during both the calibration and validation periods. The disparity between observed and simulated data most likely resulted from limitations of the existing SCS-CN and MUSLE methods in the model.This study indicated that the modification of SWAT components is needed to take rainfall intensity and its duration into account to enhance the model performance on peak flow and sediment load simulation during heavy rainfall season.