苏北近岸水域"五条沙"侵蚀发育的卫星监测   总被引：2，自引：0，他引：2  

吴永森  李日辉  吴隆业  吴碧君  辛海英 《海洋科学进展》2006,24(2):188-194

利用2000年3月26日、5月20日和9月18日Landsat-5卫星的TM和Landsat-7卫星ETM多波段多时相图像数据,经几何、辐射校正、海洋潮汐订正和多波段合成处理后,采用图象等灰度线-海图主特征地形10 m等深线配准相关法,对覆盖区内苏北岸段(32°00′~34°00′N,120°00′~123°00′E)范围内的岸滩,水下地形,潮流沙脊等重要地貌特征及其走向进行了分析和解译,并利用减法对研究区的沙洲沙脊进行点对点的经纬度计算,进而给出研究区内沙洲沙脊的逐点侵蚀与发育量值,获得了研究区内水下沙脊侵蚀发育的分析数据。结果显示,近15 a来,位于北凌河和九洋河外的蒋家沙南部有明显的侵蚀特征,范围明显收缩,而其北部有明显的向NE方向发育的特征;位于北侧的外毛竹沙等3条沙脊向N或向NNW方向延伸的趋势明显,其范围也显著加大。对比由卫星图象解译获得的10 m等深线和1986年出版的海图(10 m等深线)发现,外毛竹沙向北延伸了30 km;蒋家沙向北偏东延伸了11 km;而毛竹沙与太平沙之间的菱形“无名沙”向北延伸了约11 km。  相似文献   

中国五大湖三角帆蚌形态差异分析   总被引：49，自引：8，他引：49       下载免费PDF全文

钱荣华  李家乐  董志国  郑汉丰  李应森  袁伟康 《海洋与湖沼》2003,34(4):436-443

运用三种多元分析方法 ,采用 1 0个形态比例性状 ,对中国五大湖地理种群与诸暨人工群体三角帆蚌的形态差异进行了比较研究。聚类分析与主成分分析结果表明 ,太湖种群与巢湖种群形态最近 ,而洪泽种群的趋异程度最大。主成分分析构建了 3个主成分 ,其贡献率 :主成分 1为 2 7 87% ,主成分 2为 1 4 2 6% ,主成分 3为 1 1 91 % ,累积贡献率为 5 4 0 4 %。判别分析结果表明 ,5种群及人工群体形态差异显著 (P <0 0 1 )。建立了 5种群及人工群体的判别函数 ,其判别准确率P1 为 73 33%— 86 67% ,P2 为 72 73%— 1 0 0 % ,综合判别率为83 33%。  相似文献   

文化旅游目的地可持续发展竞争力评价研究——天津“五大道”案例     

王庆生  张亚州 《地域研究与开发》2017,36(2)

基于对可持续发展概念的广义认知,梳理了文化旅游目的地可持续发展的相关进展,依据旅游目的地可持续发展竞争力模型,建立了文化旅游目的地可持续发展竞争力评价指标体系及各项评价指标的量化方法,构建了文化旅游目的地可持续发展竞争力评价模型及评价标准,并以天津“五大道”为例进行了研究.结果表明:天津“五大道”文化旅游区处于初等发展水平向中等水平过渡阶段,今后应通过创新管理体制、加大公益性投入、塑造文化旅游品牌、强化旅游配套以及关注社区发展来进一步提升其作为天津标志性文化旅游目的地的地位与影响.  相似文献   

珠江口赤潮生成的天气分型研究     

任湘湘  何恩业  李海  蔡怡 《海洋预报》2007,24(3):46-58

赤潮的爆发是生物、化学、物理等多因素综合作用的结果。温度、风力、风向、气压等气象条件,海况、潮汐、海流及海水的理化特征,如海水温度、盐度、营养盐、微量元素等都是赤潮爆发的重要因子或诱导因素。当前由于海洋生态领域的数值预报仍不成熟,国内的赤潮预测主要还是依靠经验和统计方法为主,如气象条件预报法、水文条件预报法、化学条件预报法、生物条件预报法、卫星遥感预报法或是综合预报法等。本文根据2001年～2005年《沿海海洋赤潮专报》中广东省阳江到汕尾沿海(112°～116°E)即珠江口地区发生赤潮的记录,使用NCEP再分析数据,从气象条件诱发赤潮的角度分析得出最易引发珠江口赤潮的5种天气形势,并用相关性分析方法得出其中两种天气形势的典型场,对预测珠江口沿海的赤潮发生具有一定的指导意义,可在实践中加以应用。  相似文献   

东北地区“五化”协调发展的格局演变及影响机制     

白雪  宋玉祥  浩飞龙 《地理研究》2018,37(1):67-80

“五化协调”是经济新常态背景下,国家现代化建设的必然选择。利用多指标综合指数法、耦合协调度模型、个体效应与时点效应模型,从新型工业化、信息化、新型城镇化、农业现代化、绿色化角度选取指标（以下简称“五化”）,构建“五化”协调发展评价指标体系,探究东北振兴前后20年间（1993-2013年）东北地区40个地市单元“五化”协调发展变化情况。结果表明：东北地区“五化”协调发展水平较低,仍处于失调阶段,但增长趋势显著,具有明显的时间阶段性与区域差异性。时间上可划分为1993-2002年波动期、2003-2008年增长期、2009-2013年平稳期三个阶段。区域上可划分沿哈大线形成的轻度失调区,黑龙江中部与西部、吉林西部、辽宁大部为主的中度失调区,黑龙江西北部、东部与蒙东地区为主的严重失调区三个类型。“五化”协调内部各子系统空间表现各异,分异程度依次为：农业现代化>信息化>绿色化>新型城镇化>新型工业化。从影响机制来看,教育投入、技术投入、农业投入对“五化”协调发展产生正向影响;工业水平、开发程度对“五化”协调发展产生负相影响,开放程度、资本投入、治理投入未对协调造成明显影响。  相似文献   

Interannual variation of East Asian summer monsoon and its impacts on general circulation and precipitation     

YU Shuqiu  SHI Xiaohui  LIN Xuechun 《地理学报》2009,19(1):67-80

Using NCEP/NCAR reanalysis geopotential height (GHT) and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure (SLP) and precipitation observations from more than 600 stations nationwide in June–August from 1951 to 2006, and focusing on the East Asia–West Pacific region (10o–80oN, 70o–180oE), interannual variation of East Asian summer monsoon (EASM) and its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such as 9-point high pass filtering, empirical orthogonal function (EOF) analysis, composite analysis and other statistical diagnosis, etc. It is concluded as follows: (1) EOF analysis of SLP in the East Asia–West Pacific region shows the existence of the zonal dipole oscillation mode (APD) between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity index of EASM. (2) EOF analysis of GHT anomalies at 500 hPa in the East Asia–West Pacific region shows that the first EOF mode is characterized with an obvious meridional East Asian pattern (EAP), and EAP index can also be used as an EASM intensity index. (3) The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa (or 850 hPa). The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient of –0.23, which passes the confidence test at 0.10 level. (4) Both APD and EAP indexes are closely correlated with precipitation during flood-prone season in China and precipitation rate over the East Asia–West Pacific region. The significant correlation area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern Japan, and the former is a positive correlation and the latter is a negative one.  相似文献   

Vent area and depositional mechanisms of the Upper Member of the Neapolitan Yellow Tuff (Campi Flegrei, Italy): new insights from directional fabric through image analysis     

Laura Valentini  Bruno Capaccioni  Piermaria Luigi Rossi  Roberto Scandone  Damiano Sarocchi 《Bulletin of Volcanology》2008,70(9):1087-1101

In order to provide new information about the source area and depositional mechanisms of the Upper Member of the Neapolitan Yellow Tuff (NYT), a prominent pyroclastic deposit of the Campi Flegrei Volcanic District (southern Italy), statistics on directional fabric, by means of computer-assisted image analysis on 32 rock samples, were compiled. Seventeen samples were collected along vertical direction on two selected exposures and fifteen were taken from outcrops widely distributed all around the Campi Flegrei Volcanic District. Fabric measurements within the investigated successions reveal a vertically homogeneous direction of the mean particle iso-orientation, with considerable variability in the strength of particle iso-orientation even at cm-scale. The existence of particle iso-orientation can be related to continuous sedimentation from a concentrated bedload region beneath suspension currents, producing massive or inversely graded beds by traction carpet sedimentation. The considerable vertical variability in the strength of iso-orientation is the result of very unstable flow regimes, up to the extreme condition of discrete depositional events, with a variable combination of traction carpet and/or direct suspension sedimentation. The vertical homogeneity in the mean orientation values, found in the investigated sections, may derive from the sequential deposition of laminae to thin beds, whose relatively flat upper surfaces were unable to significantly deflect the depositional system of the following currents. According to the observed homogeneous mean particle orientation values along the investigated vertical profiles, samples collected through areal distribution are considered representative of the local paleo-flow directions of the whole deposit. The mean directions of the samples collected areally show two different coherent patterns which point to the existence of two different source areas. The first, which includes all samples from the northern outcrops, appears to converge in a narrow area about 2 km NE of the town of Pozzuoli, largely in coincidence with the inferred area on the basis of the pumice fall distribution. The second, which includes samples from Capo Miseno and Posillipo areas, points to the central part of the Pozzuoli Bay, about 4 km offshore the town of Pozzuoli.  相似文献   

Identification of fuel samples from the Prestige wreckage by pattern recognition methods   总被引：1，自引：0，他引：1  

Fernández-Varela R  Andrade JM  Muniategui S  Prada D  Ramírez-Villalobos F 《Marine pollution bulletin》2008,56(2):335-347

A set of 34 worldwide crude oils, 12 distilled products (kerosene, gas oils, and fuel oils) and 45 oil samples taken from several Galician beaches (NW Spain) after the wreckage of the Prestige tanker off the Galician coast was studied. Gas chromatography with flame ionization detection was combined with chemometric multivariate pattern recognition methods (principal components analysis, cluster analysis and Kohonen neural networks) to differentiate and characterize the Prestige fuel oil. All multivariate studies differentiated between several groups of crude oils, fuel oils, distilled products, and samples belonging to the Prestige's wreck and samples from other illegal discharges. In addition, a reduced set of 13 n-alkanes out of 36, were statistically selected by Procrustes Rotation to cope with the main patterns in the datasets. These variables retained the most important characteristics of the data set and lead to a fast and cheap analytical screening methodology.  相似文献   

一类西太平洋副热带高压双脊线过程维持机制初探   总被引：2，自引：1，他引：1       下载免费PDF全文

祁莉  张祖强  何金海  陈桦 《地球物理学报》2008,51(3):682-691

本文通过对1979~2005年5~10月发生在西太平洋地区的156个副热带高压双脊线过程进行统计分析,发现87.82%的双脊线过程的出现是因为南侧新生一脊线,而且有明显的“季节锁相”,即其发生频数在7月中旬至9月中旬有两个峰值.历年过程中最典型的“南生南存型”双脊线过程的合成分析表明该类双脊线过程形成、维持和消失与副高南侧外围东风波系统自东南向西北传播发展密切相关.500 hPa距平环流演变显示北侧脊线的减弱消失符合气候规律,东风波槽前的异常气旋仅影响副高北侧脊线位置;而东风波槽后的异常反气旋性环流有利于南侧脊线异常发展与维持,造成该类双脊线过程结束后副高异常偏南.进一步分析发现,东风波和西太平洋副热带高压的相互作用改变了副高区域垂直运动分布.这一方面改变了经向风的分布,使500 hPa副高南侧脊线区域地转涡度平流项发展;另一方面引起非绝热加热垂直分布不均匀,在两脊线之间诱生一异常气旋性环流,在南侧脊线区生成异常反气旋环流.因此,东风波与西太平洋副热带高压的相互作用可能会造成副高的不连续南退,这对副高预报有一定预示作用.  相似文献   

河南省区域暴雨的客观分型   总被引：3，自引：0，他引：3  

布亚林  郑世林 《气象与环境科学》2000,(1):8-9

从多层聚类分析入手,利用微机对１９８０～１９９５ 年河南省２１３ 场区域暴雨过程的５００ ｈＰａ 高度场进行客观分型,得出了４ 类天气形势及其与暴雨落区的对应关系。  相似文献