基于GIS的青神县暴雨洪涝灾害风险区划

随着全球变暖,气候发生变化,青神县极端天气事件频发,气象灾害特别是暴雨洪涝的发生频率有增加的趋势,给国民经济和社会发展造成重大的损失。本文主要根据气象与气候学、农业气象学、自然地理学、灾害学、自然灾害风险管理等基本理论,在GIS技术的支持下,采用风险指数法、加权综合法、自然断点等方法,绘制青神县暴雨洪涝灾害风险区划图,对青神县暴雨洪涝灾害风险进行分析和评估。结果表明,青神县高风险区和次高风险区主要分布在罗波乡、汉阳镇,以及沿江河流域,其余大部为中等及以下风险区。     

Coherent Structures and the Dissimilarity of Turbulent Transport of Momentum and Scalars in the Unstable Atmospheric Surface Layer

Atmospheric stability effects on the dissimilarity between the turbulent transport of momentum and scalars (water vapour and temperature) are investigated in the neutral and unstable atmospheric surface layers over a lake and a vineyard. A decorrelation of the momentum and scalar fluxes is observed with increasing instability. Moreover, different measures of transport efficiency (correlation coefficients, efficiencies based on quadrant analysis and bulk transfer coefficients) indicate that, under close to neutral conditions, momentum and scalars are transported similarly whereas, as the instability of the atmosphere increases, scalars are transported increasingly more efficiently than momentum. This dissimilarity between the turbulent transport of momentum and scalars under unstable conditions concurs with, and is likely caused by, a change in the topology of turbulent coherent structures. Previous laboratory and field studies report that under neutral conditions hairpin vortices and hairpin packets are present and dominate the vertical fluxes, while under free-convection conditions thermal plumes are expected. Our results (cross-stream vorticity variation, quadrant analysis and time series analysis) are in very good agreement with this picture and confirm a change in the structure of the coherent turbulent motions under increasing instability, although the exact structure of these motions and how they are modified by stability requires further investigation based on three-dimensional flow data.     

Changes in timber haul emissions in the context of shifting forest management and infrastructure

Background  

Although significant amounts of carbon may be stored in harvested wood products, the extraction of that carbon from the forest generally entails combustion of fossil fuels. The transport of timber from the forest to primary milling facilities may in particular create emissions that reduce the net sequestration value of product carbon storage. However, attempts to quantify the effects of transport on the net effects of forest management typically use relatively sparse survey data to determine transportation emission factors. We developed an approach for systematically determining transport emissions using: 1) -remotely sensed maps to estimate the spatial distribution of harvests, and 2) - industry data to determine landscape-level harvest volumes as well as the location and processing totals of individual mills. These data support spatial network analysis that can produce estimates of fossil carbon released in timber transport.     

《甘肃省长城资源分布图》的设计与编制

《甘肃省长城资源分布图》是甘肃省首次利用长城资源调查资料编制的系列专题图,该图系统地表达了甘肃省境内历代长城的分布、走向、构成、类型、保存现状,以及长城沿线关堡、单体建筑、相关遗存的分布。本文介绍了该系列地图设计和编制的总体思路、内容结构、编辑技法、质量控制等,对其他长城分布图的编制具有一定的参考价值。     

Updating the Phase 1 habitat map of Wales, UK, using satellite sensor data

The Phase 1 Survey is the most comprehensive and widely used national level map of semi-natural habitats in Wales. However, the survey was based largely on field survey and was conducted over several decades, before being completed in 1997. Given that resources for a repeat survey were limited, this study has used an object-orientated rule-based classification implemented within eCognition of multi-temporal satellite sensor data acquired between 2003 and 2006 to map semi-natural habitats and agricultural land across Wales, thereby allowing a progressive update of the Phase 1 Survey. The classification of objects to Phase 1 habitat classes was undertaken in two steps; firstly the landscape of Wales was divided into objects using orthorectified SPOT-5 High Resolution Geometric (HRG) reflectance data (10 m spatial resolution) and Land Parcel Information System (LPIS) boundaries. A rule-base was then developed to progressively discriminate and map the distribution of 105 sub-habitats across Wales based on time-series of SPOT HRG, Terra-1 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Indian Remote Sensing Satellite (IRS) LISS-3 data, derived datasets (e.g., vegetation indices, fractional images) and ancillary information (e.g., topography). The rules coupled knowledge of ecology and the information content of these remote sensing data using a combination of thresholds, Boolean operations and fuzzy membership functions. A second rule-base was then developed to translate the more detailed sub-habitat classification to Phase 1 habitat classes. Indicative accuracies of the revised Phase 1 mapping, based on comparisons with the later Phase 2 survey (for selected habitats), were >80% overall and typically between 70% and 90% for many classes. Through this exercise, Wales has become the first country in Europe to produce a national map of habitats (as opposed to land cover) through object-orientated classification of satellite sensor data. Furthermore, the approach can be adapted to allow continual monitoring of the extent and condition of habitats and agricultural land.     

景观格局在地理国情综合统计中的应用研究

在地理国情综合统计分析的研究中,利用景观格局能够进行生态协调性和地表覆盖景观格局分析。在景观格局分析中,常用的方法是景观格局指数。本文对景观格局指数在黑龙江省地理国情普查的两个实验区的应用进行了研究与分析。     

遥感影像信息在澳门、磨刀门海域工程建设中的应用及其效益

本文介绍了计算机处理和光学处理相结合的信息提取方法并得到显著效益。根据澳门海域和磨刀门海域工程建设中的实际需要,成功地运用遥感影像信息为澳门海域工程物理模型试验提供了模型水流流态与原型水流流态相似性的验证,为磨刀门海域围垦工程提供了水下潜坝的动态影像信息,并取得了较好的社会效益和经济效益。     

汶川地震灾后农田和森林植被恢复遥感监测

2008年汶川8.0级特大地震对当地的生态系统造成了极大的破坏,为了评估5年来灾区农田和森林植被的恢复情况,利用逐年机载高分辨率遥感影像,结合星载遥感数据和地面调查数据,开展了灾区农林植被恢复状况监测。在农田恢复监测方面,结合2008年地震发生后以及2013年5月中旬的机载高分辨率遥感数据,采用目视解译的方式对汶川地震中受损农田的恢复状况进行监测与评估,同时利用GVG(GPS、Video和GIS)农情采样系统的作物种植成数调查结果,分析了灾后作物种植结构的变化。结果表明,灾区1592 ha受损农田,5年后仅有约17.5%得到了恢复和耕种使用。就耕地利用强度而言,重灾区耕地利用率较高,作物种植结构没有发生重大变化。在森林恢复状况监测方面,对典型区(岷江干旱河谷区和盆周山地区的3个重点区域)采用目视解译方式识别出森林变化,并结合大区域尺度规一化植被指数(NDVI)时间序列变化分析,对整个灾区的森林损毁和恢复情况做出评价。监测结果显示,汶川县、什邡市和绵竹市的森林植被恢复情况总体较好,但是一些坡度较大的损毁区、次生灾害频发区的森林尚未恢复,大区域尺度的统计结果显示,地震重灾区的46381 ha重度损毁森林植被和177025 ha中度损毁森林植被区域,完全恢复的区域占13.52%和25.84%,部分恢复的区域都占到50%。在自然恢复较为困难的区域,如汶川县中部和东北部、都江堰市北部、彭州市北部、什邡市北部、绵竹市北部、安县北部及北川县南部等,需要加强人工干预。遥感监测方法既适用于震后的农田和森林恢复状况动态监测,也适用于其他自然灾害发生时对灾区农田和森林植被破坏状况进行应急监测,具有实际应用价值和良好的发展前景。     

ArcGIS8图形二进制解读

通过对ArcG IS8 Personal Geodatabase和Enterprise Geodatabase图形二进制字段存储规律的解读,完成脱离ArcG IS环境,使用ADO直接对ArcG IS地理数据库图形二进制字段进行读写操作,为地理资源共享提供了一种新途经,同时提高了ArcG IS8地理数据库应用的灵活性。     

基于MapXtrme2004的WebGIS系统的研究与开发

本文通过介绍.NET框架用于Web开发的主要技术ASP.NET和ADO.NET的技术优点以及MapInfo公司针对.NET环境开发的新组件Mapxtreme2004,通过分析Mapxtreme2004的结构组成总结了Mapxtreme2004用于WebGIS开发的主要方法类的用途,并着重研究了在.Net框架下利用Mapxtreme2004进行WebGIS开发的可行性及主要功能特点。