A HORIZONTAL 2-D HYDRAULIC NUMERICAL MODEL AND IT’S APPLICATIONS TO FLOOD FORECAST

1 INTRODUCTION There were many flood disasters in China in recent years. When the water level in a river is very high, weak parts of its dike may be destroyed resulted in the submersion of the protected land and properties. It is of significance for decision-makers to exactly predict the processes of flood propagation during flood control. There are many modes of dike bursting, such as seepage destroying by overflow on top of dike caused by dike body sinking induced by piping and soil fl…     

Diagnosis of earth-fill dams by synthesised approach of sounding and surface wave method

The spatial distribution of the strength inside the earth-fill is identified by the sounding tests. In this research, the Swedish weight sounding (SWS) is employed, and the spatial high-density test is performed to identify the spatial correlation structure. Furthermore, the synthesised approach of the SWS and surface wave method, which is one of the geophysical method, is proposed to compensate the shortage of each approach. Consequently, the correlation structure of an earth-fill could be identified accurately, and the high resolution of the spatial distribution could be visualised based on the survey results.     

Growth Of The Summer Daytime Convective Boundary Layer At Anand

The heights of the daytime convective boundary layer (CBL), computed by a one-dimensional model for a bare soil surface at a semi-arid station,Anand, during the dry and hot summer month of May 1997, are presented. As input, the model requires surface heat flux, friction velocity and air temperature as functions of time. Temperature data at the one-metre level from a tower and sonic anemometer data at 9.5 m collected during the period 13–17 May 1997 in the Land Surface Processes Experiment (LASPEX-97) are used to compute hourly values of surface heat flux, friction velocity and Obukhov length following the operational method suggested by Holtslag and Van Ulden [J. Climate Appl. Meteorol. 22,517–529 (1983)]. The model has been tested with different values for the potential temperature gradient ( ) above the inversion. The model-estimated CBL heights comparefavourably with observed heights obtained from radiosonde ascents.     

基于“网络工程”的GPS联测资料分析我国在欧亚板块中的运动规律

应用“中国地壳运动观测网络”1998年到 2 0 0 0年的多期 GPS联测数据 ,得到“网络工程”基准站和基本站各点在 ITRF97框架下的速度场 ,以及相对于 NNR- NUEARL1A模型的中国大陆板内运动速度场和相对于某一单站 (如 CHAN站 )的速度场 ,并对速度场信息的可靠性进行了初步分析。     

Effects of the number of stations and time resolution on derivation

For at least 30 years now it has been well known that the Dst index can be modelled using the solar wind as input. Since then, many attempts have been made to improve the predictability of Dst using different approaches. These attempts are useful, for instance, to understand which features of the solar wind–magnetosphere interactions are most important in producing magnetospheric activity and how the Dst index would improve the space weather forecast. The Dst index is by far the most reliable and simple indication that a magnetic storm is in progress. In this work, the effect of using more than four magnetic stations and shorter time intervals than the hourly averages used in Sugiura's procedures is evaluated. The discussion is based on the results presented by Burton in 1975 and Feldstein in 1984 considering 4 or 12 magnetic stations and time averages of 2.5 min for a magnetic disturbed period that occurred from February 7–28, 1967, including two geomagnetic storms. The analysis has shown that the global representation of a magnetic storm by the standard Dst (Sugiura) is well preserved either using 4, 6, 12 magnetic stations or using 1 h, 2.5 min 1 min averages. A brief review of the current understanding of Dst has been included to support the discussions. The analysis performed has shown that a more refined Dst index (time and number of stations>4) would be useful to investigate the intrinsic processes and the different current systems involved in the ring current development during magnetic storms; the standard Dst, as it is conceived, is quite adequate to monitor geomagnetic storms and identify their overall features; concerning the magnetic stations normally considered, the inclusion of higher magnetic latitude stations (>35) may underestimate the observed Dst.     

双核型空间结构模式及其在世界地理研究中的应用

作者在我国沿海和沿江地区的空间结构进行深入研究的基础上,发现了一种新的空间结构模式,即双核型空间结构模式。本文在对这一模式进行理论分析的基础上,初步探讨也该模式在世界地理研究中的应用：①指出全球最大的双核结构由全球最大的港口城市鹿特丹和全球最大的内河港口城市杜伊斯堡所组成;②作为推动美国区域经济发展的最重要的一个轴线－“美国经济地理横轴”,是一由芝加哥和纽约组成的双核结构;③新旧首都构成一特殊的双     

纳入空间自相关的FLUS模型在土地利用变化多情景模拟中的应用

FLUS模型是一种新型的土地利用变化模拟模型,应用前景广阔。本文通过在FLUS模型的人工神经网络(Artificial Neural Network,ANN)训练模块中引入空间自相关因子来改进模型,以珠江三角洲地区为例,基于2009年、2015年土地利用数据和一系列驱动因子对改进的模型进行了验证,并利用该改进的FLUS模型模拟了2035年研究区在3种情景下土地利用变化格局。结果表明:①引入空间自相关因子后各地类发生概率分布的预测精度更高,耕地、林地、建设用地、水体和未利用土地的拟合优度ROC值分别从0.819、0.928、0.885、0.855和0.861提高到0.857、0.934、0.890、0.863和0.978;②改进的FLUS模型的模拟精度有一定的提高,Kappa系数从0.732提高到0.744,FOM系数从0.077升到0.106;③情景模拟表明,3种情景下珠江三角洲建设用地和林地均将增加、而耕地均呈减少趋势。但不同情景下模拟的土地利用格局也存在显著差异:基准情景下,建设用地明显扩张且大幅侵占耕地。耕地保护情景下,耕地面积保持在合理水平,建设用地蔓延扩张趋势得到遏制,土地利用布局总体趋向合理。生态保护情景下,耕地、林地和水体得到较好保护,建设用地布局更为合理,土地利用可持续性明显提高。     

利用Access97编制科技论文登记及统计数据库

介绍利用Access97编制科技论文登记数据库的具体过程及使用方法。通过该数据库，可以及时将发表的科技论文入库。当论文全部入库后，可以方便地进行查询及统计，从而得出有效的数据，大大提高了工作效率。     

Global tectonics and the plate motion obtained from the ITRF97 station velocity vectors

~~Global tectonics and the plate motion obtained from the ITRF97 station velocity vectors@马宗晋 @任金卫 @张进~~