Temporal precipitation estimation from nearby radar reflectivity using dynamic factor analysis in the mountainous watershed – a case during Typhoon Morakot

The radar reflectivity (Z)–rain intensity (R) relationship fluctuates in both temporal and spatial scales. The dynamic factor analysis (DFA) and min/max autocorrelation factor analysis (MAFA) was specifically designed for considering various space–time integrations of gauge rainfall and radar reflectivity. We detect representative radar reflectivity observed around rainfall stations that were most responsible for rainfall intensity and identify the crucial patterns of the radar reflectivity in the Kaoping River watershed during Typhoon Morakot. Result shows that the MAFA and DFA can reduce the uncertainty of the dynamic Z‐R relationship effectively. The MAFA separates an entire area into two subareas (southern and northern areas) according to the relationships between the radar reflectivity and min/max autocorrelation factor (MAF) axes. For both areas, the different extents of temporal rainfall correlated with the radar reflectivity were determined using DFA. Especially in the northern area, the radar reflectivity was significantly related to the rainfall intensity for most stations without mountain blockage. Mountain blockages associated with the presence of terrain and wind direction were inferred the major factors that affected the relationship between radar reflectivity and rainfall intensity in the mountainous watershed. Further study can consider the terrain effect and meteorological information, such as wind speed and direction in the DFA model, with the dominant radar reflectivity to estimate the temporal rainfall patterns. Copyright © 2012 John Wiley & Sons, Ltd.     

甘肃省县域经济空间差异及其演化研究

以甘肃省县域人均GDP为测度指标,运用变异系数、锡尔系数和空间自相关等方法,结合Arc GIS 10.2及Geo DA软件对甘肃省2001~2013年县域经济的空间差异及演变过程进行研究。结果表明,在时间上甘肃县域经济的差异在逐年增大,2011年后呈现急剧增大的趋势;在空间上县域经济总体有显著的聚集态势,局部空间分析发现,甘肃省县域经济两极分化明显,河西地区经济发展水平较高,陇中和陇南的大部分县域经济发展水平较低;从分解分析来看,分区内部差异略大于分区之间差异,区域内部差异是构成差异的主要因素。     

Shallow geology characterization using Rayleigh and Love wave dispersion curves derived from seismic noise array measurements

The local geology and shallow S-wave velocity structure of a site are recognized to be key factors for the increase in the damaging potential of seismic waves. Indeed, seismic amplitudes may be amplified in frequency ranges unfavorable for building stock by the presence of soft sedimentary covers over lying hard bedrock. Hence, microzonation activities, which aim at assessing the site response as accurately as possible, have become a fundamental task for the seismic risk reduction of urbanized areas. Methods based on the measurement of seismic noise, which typically are fast, non-invasive, and low cost, have become a very attractive option in microzonation studies.Using observations derived from seismic noise recordings collected by two-dimensional arrays of seismic stations, we present a novel joint inversion scheme for surface wave curves. In particular, the Love wave, the Rayleigh wave dispersion and the HVSR curves are innovatively combined in a joint inversion procedure carried out following a global search approach (i.e., the Genetic Algorithm).The procedure is tested using a data set of seismic noise recordings collected at the Bevagna (Italy) test-site. The results of the novel inversion scheme are compared with the inversion scheme proposed by Parolai et al. (2005), where only Rayleigh wave dispersion and HVSR curves are used, and with a cross-hole survey.     

基于DEA和空间自相关的我国土地市场化程度分析

运用数据包络分析(DEA)方法、空间自相关方法对我国土地市场化程度及其空间分布格局进行研究。结果表明,2003年以来我国土地市场化进程大致可划分为两个阶段:一是2004-2006年的波动发展阶段,二是2006年以来的迅猛发展阶段;对应的市场化程度值由2004年的0.65升至2008年的0.88,市场化程度不断提高。空间自相关分析表明市场化程度高值集聚区主要位于江苏、浙江、广东、江西4省,这些地区土地市场化改革实施较早,区域间交流联系紧密,市场化程度普遍较高;低值集聚区位于新疆、青海,这两省(区)受区位、资源等条件限制,经济社会发展水平落后,土地市场化发育不够完善,而周围省份同样处于中西部欠发达地区,土地市场化程度普遍较低。对于土地市场化程度评价而言,不仅要考虑出让方式,出让价格也是重要因素;同时,土地市场化程度不仅取决于各地区自身经济社会发展水平,还受相邻地区市场化发展程度的影响。     

广州市中心城区餐饮店空间分异与机制差异研究——基于传统店与外卖店的对比

O2O模式（Online to Offline）使餐饮店经营模式与空间分布发生巨大变化,餐饮店空间分布现象与机制成为研究热点。本文将餐饮店分为仅提供堂食服务的传统店和同时提供堂食与餐饮配送服务的外卖店,利用核密度、双变量空间自相关、半变异函数、标准差椭圆、空间计量模型等方法,分析广州市中心城区传统店与外卖店的空间分异与机制。研究发现：① 2020年传统店主要集聚于自荔湾区多宝街道东至天河区石牌街道;外卖店呈多中心分布,以天河区天河南街道、冼村街道、海珠区江南中街道和赤岗街道为核心;二者在越秀区中部、天河区西南部、车陂街道、海珠区西北部等有多处高高集聚区。② 两种餐饮店空间分异较明显,易受随机性因子影响;外卖店较少分布在越秀区和荔湾区,整体分布范围较小,仅有很弱的空间自相关性,更多呈零散分布特征。③ 餐饮店空间分布受人口密度和餐饮店集聚的正作用;但受教育程度、路网密度、邻近高等院校、公交站、商圈等因素能提高外卖店比例,外卖店有更高店铺付租能力,更邻近地铁站和低经济密度地区,传统店则与其相反。     

基于多方法融合的低产低效气井优选

随着致密气田的深入开发,低产低效井逐年增加,已经成为制约气田开发的关键问题之一。以苏里格气田某区块30口气井为研究对象,引入产量贡献率作为动态分类指标,运用气井产量贡献率累计分布曲线的类分割点将气井划分为4类。以纵向合采砂体数、有效砂体厚度、孔隙度、渗透率和含气饱和度等参数作为静态评价指标,采用熵权-理想点法,对气井进行静态分类。基于动态和静态分类结果,引入自相关距离判断异常值点,进行低产低效气井优选。研究表明,Ⅰ、Ⅱ、Ⅲ、Ⅳ类气井的储层质量依次变差,累计产量依次减小;4口气井为低产低效井,优选结果符合生产实际。该研究成果可为气田进一步挖潜的选井、选层提供一种新的技术途径。     

Complexity reduction in choropleth map animations by autocorrelation weighted generalization of time-series data

Choropleth map animation is widely used to show the development of spatial processes over time. Although animation congruently depicts change, the rapid succession of complex map scenes easily exceeds the human cognitive capacity, causing map users to miss important information. Hence, a reduction of the visual complexity of map animations is desirable. This article builds on research related to complexity reduction of static choropleth maps. It proposes value generalization of choropleth time-series data in space and time, by using a method that adapts to the degree of global spatiotemporal autocorrelation within the dataset. A combination with upstream algorithms for local outlier detection results in less complex map animations focusing on large-scale patterns while still preserving significant local deviations in space and time. An according software application allows for in-depth exploration of the spatial and temporal autocorrelation structures in time-series data and provides control over the whole process of generalization.     

基于房产网站数据的商品住宅价格空间分布研究——以成都市为例

从安居客房产网站自动获取成都市的商品住宅资料,利用GIS方法分析成都市商品住宅价格的空间分布特征,得出了成都市商品房价格空间分布结果和发展趋势。     

Management implications of spatiotemporal non-stationarity in municipal water consumption patterns and drivers

This study analyzed the individual and joint influences of social, urban, and physical drivers on patterns of county-scale municipal water consumption (MWC) the for the state of Texas using a cross-sectional research design on three distinct temporal slices (1990, 2000, and 2010). Global multiple linear regression models and measures of global and local spatial association were combined to determine which drivers significantly influenced county-scale per capita MWC, whether or not the statistically significant drivers varied over time, and to assess the degree to which the patterns and drivers of MWC exhibited spatial stationarity. Overall results suggested the social, urbanized, and physical environments contributed significantly to the patterns of per capita MWC to varying degrees in each year. The social and urbanized environments consistently exerted the strongest influences on per capita MWC, while the physical environment was generally less important. The social environment had the greatest cumulative influence in all three years, and the urbanized environment singly accounted for the majority of the variation in per capita MWC when the joint influences of the other significant drivers were considered. Spatial analysis of MWC patterns and drivers suggested that they both exhibited weak to moderate degrees of spatial non-stationarity in each year, as well as that MWC patterns and drivers may be sensitive to regional and climatic boundaries. Identification of temporally consistent MWC drivers merged with longitudinal and cross-sectional research designs can improve water management strategies by offering managers greater insight into the relationships between landscape change and water consumption patterns.     

基于空间自相关分析方法的渤海湾赤潮遥感叶绿素浓度研究

引入地学统计学中的空间数据分析方法,利用探索性分析、全局空间自相关和局部空间自相关分析对渤海湾赤潮爆发前后的遥感叶绿素浓度数据进行了研究。结果表明,渤海湾叶绿素浓度在相邻空间位置上具有高度的正空间自相关性;赤潮前渤海湾叶绿素浓度整体较低,但局部地区的叶绿素浓度表现出较大的上升随后几天又出现下降的异常现象;叶绿素浓度的全局空间自相关指数Moran's I值在赤潮爆发前变化幅度不大,在赤潮期间表现出一些不规则的异常变化;局部Moran's I的高-高型聚集在赤潮前主要分布在渤海湾南半部,赤潮期间出现分散并逐步转移到离岸区域,赤潮后期聚集在近岸区域。分析了其中的一些变化特征及异常情况,这些异常现象有可能是赤潮发生的预兆性信号,可为赤潮预报与应急提供一种新的尝试性模式。