GIS在1∶5万区调中的应用浅谈——以榆关镇幅1∶5万区调为例

文章以榆关镇幅为例，阐述了ＧＩＳ在１∶５万区调中的应用问题。物化探遥感资料按地质需求由计算机处理成各种图件，地形图则划分图层并赋予其属性，建立地形资料ＧＩＳ系统；野外工作采用手工记录，室内微机处理的工作方式；野外连图采用手工，而后清绘，通过扫描输入微机。按地质体分布、构造等建立图层并用地理编码将其与数据库相连，叠加、编排图层，编制地质图，最终建立１∶５万区调ＧＩＳ系统。     

北京黄庄—高丽营断层,八宝山断层中段活动性综合研究

在黄庄－高丽营断层及八宝山断层中段布设了监测断层活动性的水淮、短边测距、重力、地磁等的共点同步观测网，分析了各观测量的时空分布及相互关系。研究认为，黄庄－高丽营断层处于应变能积累的闭锁状态；八宝山断层处于蠕动或旷动的状态；应用形变及重磁手段共点同步综合监测断层活动性，可以获得断层活动的微动态的丰富信息。     

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亚洲高山区积雪物候时空动态及其对气候变化的响应

以亚洲高山区为研究区,在对2000—2020年逐日MODIS积雪产品进行去云处理的基础上提取了每一水文年的积雪日数（snow-covered days, SCD）、积雪开始日期（snow onset date, SOD）、积雪结束日期（snow end date, SED）和积雪持续日数（snow duration days, SDD）等积雪物候参数,并分析了积雪物候时空动态特征及其与气候变化的响应关系。结果表明：亚洲高山区积雪物候空间差异较大,并呈现出主要受海拔影响的垂直地带性分布规律。研究区SED主要集中在3—6月,在低海拔区SED出现在3月份及以前,而高海拔山区则推迟到6月份及以后;SOD主要集中在9—12月,高海拔山脉及高纬度地区的SOD出现较早,而低海拔区的SOD多出现在11月及以后。近20年,研究区SDD主要呈缩短趋势,在13.5%的区域呈显著缩短,而仅7.4%的区域为显著延长;SED主要呈提前趋势,在15.8%的区域显著提前,而仅8.8%的区域为显著推迟;SOD主要呈推迟趋势,在11.4%的区域表现为显著推迟,在8.2%的区域为显著提前。亚洲高山区积雪物候年际变化对气候变化的响应关系明显,积雪累积期气温是影响SOD年际变化的主导因子,而融雪期气温是影响SED年际变化的主导因子;气温的上升,导致了SOD的推迟、SED的提前和SDD的缩短。     

基于地理加权回归的青藏高原季节冻土区土壤有机碳空间分布研究

青藏高原土壤有机碳储量（soil organic carbon stocks, SOCS）对于区域生态环境演替具有重要作用, 但是其空间分布数据还比较缺乏, 特别是季节冻土区的数据较少。基于378个土壤剖面数据, 结合与土壤有机碳（soil organic carbon, SOC）相关的地形、 气候以及植被等环境因子, 使用地理加权回归（geographically weighted regression, GWR）模型模拟了青藏高原季节冻土区0 ~ 30 cm、 0 ~ 50 cm、 0 ~ 100 cm和0 ~ 200 cm深度的SOC总量和空间分布。结果表明： 青藏高原季节冻土区SOCS自东南向西北递减, 表层0 ~ 200 cm的SOC总量约15.37 Pg; 季节冻土区不同植被类型SOC从大到小依次为森林、 灌丛、 高寒草甸、 高寒草原和高寒荒漠; 各土壤类型中棕壤、 黑钙土和泥炭土的SOC最大, 而棕钙土、 棕漠土、 灰棕漠土、 风沙土、 石质土、 盐土、 冷钙土、 寒漠土以及冷漠土的SOC最小。研究结果给出了青藏高原季节冻土区SOC的总量、 空间分布及规律, 可为相关地球模式的发展提供基础数据。     

一种改进的LiDAR点云TIN迭代滤波算法

采用了设定最大内插距离和最大内插角度两个阌值,根据滤波次数动态调整了其值以达到最佳滤波效果,实现并改进了TIN迭代滤波算法。     

Investigation of ionospheric TEC changes related to the 2008 Wenchuan earthquake based on statistic analysis and signal detection

Ionospheric TEC (total electron content) time series are derived from GPS measurements at 13 stations around the epicenter of the 2008 Wenchuan earthquake. Defining anomaly bounds for a sliding window by quartile and 2-standard deviation of TEC values, this paper analyzed the characteristics of ionospheric changes before and after the destructive event. The Neyman-Pearson signal detection method is employed to compute the probabilities of TEC abnormalities. Result shows that one week before the Wenchuan earthquake, ionospheric TEC over the epicenter and its vicinities displays obvious abnormal disturbances, most of which are positive anomalies. The largest TEC abnormal changes appeared on May 9, three days prior to the seismic event. Signal detection shows that the largest possibility of TEC abnormity on May 9 is 50.74%, indicating that ionospheric abnormities three days before the main shock are likely related to the preparation process of the M_S8.0 Wenchuan earthquake.     

岷江上游土地利用的时空分异

运用土地利用变化率、土地利用类型综合转换速率、土地利用结构差异度系数和信息熵等指标,分析了岷江上游土地利用的时空分异特征.研究表明:1986～2000年间,岷江上游土地利用类型趋于多样化,土地利用结构趋于均匀化,呈现与牧草地、耕地和建筑用地挤压林地的趋势;空间单元土地利用结构整体差异性变化不大,土地利用系统不同程度地趋于复杂无序;上地利用的空间生态效应与海拔梯度、人口密度变化具有一定相关性;土地利用变化与空间生态效应变化呈现逆向关联特征;区域开发政策、人口密度、资源分布、产业活动强度等的变动驱动了土地利用时空变化.     

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Impact of the Wenchuan Earthquake on tourism in Sichuan, China

An intensive earthquake, the Wenchuan Earthquake of 8.0 on the Richter scale, struck western Sichuan, China on May 12, 2008. The earthquake has tremendously affected all industries in the quake-hit areas, with no exception ：of the local tourism. The study of the effect of the earthquake on tourism enriches the theory of tourism, and more importantly, it well serves as the foundation for policy making. The objective of this study is to outline for readers the empirical findings on the various ways that the earthquake affected the operations and viability of tourism in the quake-hit areas. This paper is mainly divided into 3 parts. The first part is to discuss the importance of tourism in the quake-hit areas. The second is to analyze the influencing factors of tourism. The third is to assess the impact of the earthquake on tourism in Sichuan in different seasons.