中国古代政治地理思想探究

中国古代具有丰富的政治地理思想和实践,对当前中国政治地理学的建设具有重要意义。本文对中国从先秦至晚清的相关文献中涉及政治地理的内容进行梳理,归纳为地利(定都、设镇)、地政(治地、安民)、地缘(安边、攘夷)三大主题,对各主题的要点进行了整理,进而探讨了这些思想与西方政治地理学相关概念的关联,并期望未来中国政治地理学对于本国的传统思想给予更多关注。     

Spatial relationship between topography and rock uplift patterns in asymmetric mountain ranges based on a stream erosion model

The spatial relationship between topography and rock uplift patterns in asymmetric mountain ranges was investigated using a stream erosion model in which the asymmetric rock uplift was given and erosion rates were proportional to the m-th power of the drainage area and the n-th power of the channel gradient. The model conditions were simple, and thus the effects of horizontal rock movement, diffusional processes, and erosion thresholds were neglected, and spatially uniform precipitation, lithology, and vegetation were assumed. In asymmetric mountain ranges, under realistic exponent conditions (m < n) and the above assumptions, the surface erosion rate is faster on the steeper side and slower on the gentler side. The topographic axis migrates away from the rock uplift axis toward the center of the mountain range owing to the contrast in erosion rates. This migration continues until the erosion is balanced with rock uplift. In a dynamic steady state, the topographic pattern is independent of the rock uplift rate as indicated by an analytical solution, and is prescribed by the rock uplift pattern and the exponents m and n. As the asymmetry of the rock uplift pattern increases, the topographic axis migrates a greater distance. The location of the topographic axis is related to the location of the rock uplift axis by a simple logarithmic function, for a wide range of m and n. The fit of the numerical results and the logarithmic function is particularly good when m = 0.5 and n = 1.0. If the rock uplift pattern in asymmetric mountain ranges is known, the value of n − 5m/4 can be constrained based on the logarithmic relation, assuming a dynamic steady state. On the other hand, if the value of n − 5m/4 is known in an asymmetric mountain range, the rock uplift pattern can be estimated directly from the topography. This relation was applied to the Suzuka Range in central Japan, and the value of n − 5m/4 was estimated for an assumed reverse fault motion.     

“蛋-黄”模型的拓展研究

通过研究不确定数据间的拓扑关系,针对"蛋-黄"模型中46个拓扑关系内部逻辑关系不清的缺点,给出了"蛋-黄"模型的邻近拓扑关系之间的动态变化图和相应的93个拓扑关系,去掉41个含"切"的拓扑关系和6个重复的拓扑关系,仍然得到46个拓扑关系,这与Cohn的理论是一致的,在完善了"蛋-黄"模型的同时提高了其空间推理能力。     

运用图论进行道路网网格模式提取

提出了一种基于图论的网格模式提取方法。该方法根据道路之间的关系生成关系图,运用交、联、提取连通分量和极大完全子图等图论算子完成模式的提取。实验结果表明,该方法能有效地进行网格模式的提取。     

城市地理信息普查系统设计及数据入库方法研究

基于珠海市数字城管项目开发成功经验,分析了城市地理信息普查的系统需求,阐述了万米格网划分、符号库设计、数据库开发、部件采集入库、软件编写、数据质量控制等影响地理信息普查的重要环节。实践证明,该方法大大提高了生产效率,取得了良好的效果,对其他城市数字化建设具有一定的借鉴作用。     

数据质量控制技术与方法研究——以禅城区第二次土地调查为例

主要研究了佛山市禅城区第二次土地调查(农村部分)的数据质量控制技术与方法,在研究二调基本流程基础上,有针对性地分析了主要流程中可能存在的质量问题,并提出了一些基于现有软件相应的数据质量控制技术与方法,该方法控制下的禅城区第二次全国土地调查数据成果通过了禅城区、佛山市、广东省以及国家的成果质量检查验收,说明本次调查的数据质量控制技术与方法达到了预期效果。     

一次典型积层混合云降水过程雨滴谱特征

利用激光雨滴谱仪观测到的资料,对2009年8月29日山东省一次典型积层混合云降水过程中雨滴谱特征进行了分析。结果表明:降水强度主要取决于最大雨滴直径,与雨滴浓度也呈正相关性,而与平均直径的关系甚微;本次降水过程中雨滴平均谱以双峰和多峰结构为主,在0.5mm左右处存在峰值;Г分布各拟合参数随时间起伏变化趋势一致,强降水时段中各拟合参数起伏变化缓慢,各值基本保持在同一水平;建立了雷达回波强度与降水强度之间的相关关系。     

一次暴雨过程中云微物理特征的卫星反演分析

利用卫星反演技术和云微物理分析方法,以陕北2006年7月2日发生的暴雨过程为例,反演了云顶粒子有效半径(Re)、云顶温度(T)等云物理特征参数,通过卫星不同时次对暴雨云团的探测资料,分析了暴雨发展过程.暴雨云团表现为多单体特征,发展旺盛期对流单体的数量明显增加、云团尺度大幅增加.根据暴雨云系中的对流云、层云、过冷水云、低云(未被高云遮挡住)4种类型,分别选择了9个代表区,用于分析这次暴雨过程中不同类型云的物理特征和垂直结构.结果表明:此次暴雨云团由多种高度的云组成,低云高度较低,温度较高,云顶在0--10℃;层云高度略高,T为-10--20℃,Re为10-20 μm,并含有连片分布的过冷水云(Re为10 μm左右);高度最高的云为对流云,镶嵌在系统性层云中或在其上发展,T最低达到-80℃左右.从云底至0℃层存在一个较厚的凝结增长带,Re为5-10μm;0--10℃层存在一个碰并增长带,Re从13-15μm增长到20～25μm,但其厚度小于凝结增长带;T<-10℃层以上存在一个深厚的冰相增长带,表明在对流云团的发展成熟期,冰相增长过程为优势云物理过程.随着云的逐渐发展,混合相增长带由厚变薄,冰化增长带增厚,晶化温度升高、高度降低,表明在对流云团发展到成熟的过程中,冰化增长带在下传,云中冰化增长过程向下传递明显.     

The CLIVAR C20C project: skill of simulating Indian monsoon rainfall on interannual to decadal timescales. Does GHG forcing play a role?

The ability of atmospheric general circulation models (AGCMs), that are forced with observed sea surface temperatures (SSTs), to simulate the Indian monsoon rainfall (IMR) variability on interannual to decadal timescales is analyzed in a multimodel intercomparison. The multimodel ensemble has been performed within the CLIVAR International “Climate of the 20th Century” (C20C) Project. This paper is part of a C20C intercomparison of key climate time series. Whereas on the interannual timescale there is modest skill in reproducing the observed IMR variability, on decadal timescale the skill is much larger. It is shown that the decadal IMR variability is largely forced, most likely by tropical sea surface temperatures (SSTs), but as well by extratropical and especially Atlantic Multidecadal Oscillation (AMO) related SSTs. In particular there has been a decrease from the late 1950s to the 1990s that corresponds to a general warming of tropical SSTs. Using a selection of control integrations from the World Climate Research Programme’s (WCRP’s) Coupled Model Intercomparison Project phase 3 (CMIP3), it is shown that the increase of greenhouse gases (GHG) in the twentieth century has not significantly contributed to the observed decadal IMR variability.     

离散空间的拓扑关系模型

在分析现有拓扑关系表达模型对离散空间目标间拓扑关系表达不足的基础上,从两个方面对现有RCC5模型进行了改进研究:基于模糊集合的分解定理,通过利用空间实体的k阶邻域构造了空间实体的模糊区域,实现了离散空间的连续化;以部分关系作为基本操作算子构建了基于三元组(P(X,Y),P(X,┐Y),P(Y,X))的拓扑关系表达模型,实现了离散空间实体间拓扑关系的表达,集成了空间拓扑和距离关系的定性表达和推理.