GIS属性数据精度的缺陷率度量统计模型

随着GIS数据采集规模的扩大和更新速度的提高，对GIS属性数据质量的检查、度量和控制变得越来越重要。基于抽样检验在测量数据精度分析中的思想，提出基抽样的缺陷率方法对GIS属性数据的精度进行度量。同时根据大多数GIS数据分层存储的特点，进一步提出采用分层抽样检验属性数据缺陷的方法，并给出基于分层抽样的属性数据精度的缺陷率模型和应用实例。     

运用GM（1，1）模型预测高填土河堤的沉降研究

采用灰色理论中的GM( 1 ,1 )模型对修河高填土河堤分别在填土期和静载期的沉降量进行了预测 ,通过同实测值的比较 ,证明灰色理论运用于高填土工程中的沉降预测是可行的 ,在实际运用中应不断代入最新的实测数据 ,以便获得更准确的结果     

砼灌注桩质量监督与分析

介绍了人工挖孔桩、钻孔桩2种砼灌注桩质量监督的关键，同时对砼灌注桩质量的判定方法进行了探讨。     

GIS分幅数字化数据的模糊匹配

在GIS数字化输入空间数据时，经常碰到分幡接边时的数据匹配问题，本文提出了一种建立于综合考虑距离和整体结构的模糊数据匹配算法，并给出了应用实例。     

利用化学因子预测赤潮的可行性探讨

本文从化学的角度对赤潮预报进行了可行性探讨 ,分析了部分化学参量作为赤潮预报依据的机理 ,综述了赤潮化学预报的研究现状 ,并对今后的赤潮预报研究进行了探讨.     

MapGIS地质图件向ArcGIS系统中的转换及应用

由于不同时期和阶段形成的地质图件,采用不同的GIS软件平台进行绘制,国内地矿部门常用MapGIS软件编制地质图件,而目前国土资源信息化建设或资料集成中普遍采用ArcGIS作为软件平台,两者数据格式相互不兼容,因此,两种数据的共享和转换是工作中遇到的常见问题,本文通过实例讲解了地质图件的转换过程,为数据转换提供一种新的思路.     

基于离散元法的水力压裂数值模拟

不同条件下水压裂隙的发展特性对有效开采页岩气具有重要的指导作用。针对岩体在微观上为颗粒和孔隙的结构系统,提出离散元水力压裂数值模拟方法,离散元能量转化和能量守恒计算方法,建立了相应的三维离散元模型。采用自主研发的三维离散元模拟软件Mat DEM3D,通过控制模型的竖向应变与颗粒直径,来模拟地层中的应力与压裂速率的变化。模拟结果表明:(1)水力压裂产生裂隙的数量和方向受岩石的各向异性,压力状态和变化速率所影响。(2)裂隙在压缩波传播时发展,当水压力高速增加时,诱发的裂隙数量增多,并且有效能量(断裂热)百分比也随之增加,压裂作用也变得更明显。(3)当竖向应变为零时,50%的裂隙呈垂直状态,当竖向应变为-1×10-4时,裂隙趋于沿着最大压力方向发展,竖向裂隙的百分率增大。数值模拟和能量分析为定量地研究岩石水力压裂过程提供了一个新的方法。     

IMPROVEMENT OF REGIONAL PREDICTION OF SEA FOG ON GUANGDONG COASTLAND USING THE FACTOR OF TEMPERATURE DIFFERENCE IN THE NEAR-SURFACE LAYER

The relationship between the factor of temperature difference of the near-surface layer(T_(1000 hPa)-T_(2m))and sea fog is analyzed using the NCEP reanalysis with a horizontal resolution of l°xl°(2000 to 2011) and the station observations(2010 to 2011).The element is treated as the prediction variable factor in the GRAPES model and used to improve the regional prediction of sea fog on Guangdong coastland.(1) The relationship between this factor and the occurrence of sea fog is explicit:When the sea fog happens,the value of this factor is always large in some specific periods,and the negative value of this factor decreases significantly or turns positive,suggesting the enhancement of warm and moist advection of air flow near the surface,which favors the development of sea fog.(2) The transportation of warm and moist advection over Guangdong coastland is featured by some stages and the jumping among these states.It also gets stronger over time.Meanwhile,the northward propagation of warm and moist advection is quite consistent with the northward advancing of sea fog from south to north along the coastland of China.(3) The GRAPES model can well simulate and realize the factor of near-surface temperature difference.Besides,the accuracy of regional prediction of marine fog,the relevant threat score and Heidke skill score are all improved when the factor is involved.     

A CASE STUDY OF NUMERICAL SIMULATION OF SEA FOG ON THE SOUTHERN CHINA COAST

This study uses numerical simulations to examine a case of sea fog that was observed from 20 to 22 March2011 on the southern China coast. The observation dataset includes observatory data, cloud-top temperature from MODIS, GPS sonde, and data from the Integrated Observation Platform for Marine Meteorology(IOPMM). The simulations are based on the Weather Research and Forecasting(WRF) model with four distinct parameter settings.Both the observations and simulations focus on the characteristics of the fog extent, boundary layer structure, and meteorological elements near the air-sea interface. Our main results are as follows:(1) The extent of mesoscale sea fog can be well simulated when the sea surface temperature has at least 0.5 ×0.5 horizontal resolution.(2) To accurately model the vertical structure of the sea fog, particularly the surface-based inversion, vertical levels must be added in the boundary layer.(3) When these model conditions are met, the simulations faithfully reproduce the measured downward shortwave radiation, downward longwave radiation, and surface sensible heat flux during the sea fog period.     

GPS动态实时打桩定位系统的框架设计与实现

在应用GPS-RTK技术实现打桩定位的基本思路的基础上,详细介绍该系统的基本框架、设计流程、计算模块和软件实现。