多光谱卫星云图的高维特征聚类与降水天气判别     

洪梅  张韧  孙照渤 《遥感学报》2006,10(2):184-190

基于静止气象卫星（GMS-5）多光谱云图的天气采样数据，分别对各样本数据在红外、水汽及可见光通道的灰度、梯度和纹理高维特征空间的投影点进行聚类分析，以确定诸天气样本在特征空间中的类属区域，进而用其对云图进行天气区的判别分类。针对传统聚类方法存在的缺点，本文采用了模糊C均值聚类（FCM）、遗传算法（GA）和模糊减法聚类（FSC）相互交叉、优势互补的思想，既克服了GA／FCM算法局部／全局寻优的不足，又可客观确定出聚类中心数目。对高维特征空间中的重叠和交叉部分的样本点类属，通过计算其与空间中各聚类中心点的欧氏距离来予以甄别，最后得到高维特征空间中各天气的类属域，实况云图中诸像素点通过计算和判断其灰度-梯度特征量在高维空间中的投影点落区位置，即可确定其天气类属，进而实现对天气区的自动分类。试验结果表明，该方法具有良好的分类效果，判别结果与天气实况基本一致。  相似文献   

基于中尺度气象模式（MM5）计算GNSS对流层水汽延时     

宋爱虎  高兴国  孔梅  江峻毅  周宁 《全球定位系统》2011,36(5):49-52

基于中尺度气象模式MM5得到的三维气象场数据,建立了渤海湾地区的湿折射率场。采用切比雪夫多项式和微积分等数学方法计算了GNSS卫星信号传播方向上的水汽延时。通过与Bernese软件处理的GNSS结果比较分析来看,二者天顶总延时相差最大不超过2cm,在1cm附近波动。得到的湿延偏差在7mm左右,最大相差10mm.MM5模式积分计算的水汽延时结果可信,具有较理想的精度。  相似文献   

基于移动测量数据的公路路况调查软件设计与实现     

李元博  王卫安  丁美  邓迅 《测绘与空间地理信息》2011,34(1):147-150

针对国内路况调查工作效率不高、周期长等问题,提出了将移动测量系统应用于公路路况调查的实现方案并分析其技术优势,同时,根据路况调查的业务特点,在数据准备、数据组织、系统设计和业务管理等方面进行了一些研究和尝试,实现了一个C/S架构的移动测量公路路况调查系统,最后对本应用的现实意义做出了总结.  相似文献   

河北省冰雹气候特征及其与环流异常的关系   总被引：3，自引：1，他引：2       下载免费PDF全文

顾光芹  史印山  池俊成  张梅 《高原气象》2011,30(4):1132-1138

根据1961-2007年河北省142个测站的冰雹实测资料、月平均气温和NCEP再分析资料,利用M-K突变检验、小波分析及相关分析等统计分析方法,分析了47年来河北省冰雹天气的时空分布特征、历史演变规律以及多雹年与少雹年的环流特征。结果表明,河北省冰雹日数年际变化明显,1994年有明显的突变,此后,雹日数减少了;河北冰雹...  相似文献   

基于多模式短期集合预报技术的热带气旋降水预报试验   总被引：3，自引：1，他引：2  

张亚洲  李盛林  邓文彬  梅华 《气象与减灾研究》2011,34(2):26-33

利用中尺度AREM和WRF模式为试验模式,由对降水预报结果影响颇大的积云和边界层参数化方案构成的10个集合预报成员,开展有限区域多模式短期集合预报在热带气旋降水预报中的应用与研究.分别研究了单个模式集合预报和多模式集合预报在热带气旋"天鹅"(0907)降水预报中的应用.试验结果表明:(1) WRF模式集合预报效果整体上...  相似文献   

江苏省汛期强降水过程的延伸期预报试验   总被引：1，自引：1，他引：0  

蒋薇  孙国武  陈伯民  项瑛  陶玫 《气象科学》2011,31(Z1)

针对汛期延伸期降水预报问题,根据大气低频振荡特性,运用低频天气图预报方法,通过分析关键区低频天气系统(低频气旋和低频反气旋)的活动特征,建立低频系统与强降水过程间的对应关系,通过低频系统的活动特征来预报降水过程.在2011年7-9月江苏省延伸期强降水过程预报试验中,低频天气图预报方法的预报效果较好,且预报时效为10 ～30 d,可以在延伸期业务预报中加以应用.此外,还运用模式统计降尺度方法预报降水落区,为强降水过程的发生提供背景依据和参考信息,具有一定的实用意义.  相似文献   

The factors controlling the partitioning of polybrominated diphenyl ethers and polychlorinated biphenyls in the water-column of the Pearl River Estuary in South China   总被引：1，自引：0，他引：1  

Chen MY  Yu M  Luo XJ  Chen SJ  Mai BX 《Marine pollution bulletin》2011,62(1):29-35

In this study, the distribution and partition of polybrominateddiphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in water from the Pearl River Estuary were investigated. A seasonal dependence for dissolved and particle phase PCB and PBDE levels was observed. A high dissolved phase level occurred in the dry season. The positive correlation between POC content in the particles and phase distribution coefficients (K_p) suggested that POC may play an important role in determining the partition of PBDEs and PCBs. A linear correlation between the observed log K_OC and log K_OW for PBDEs and PCBs was found with slopes less than one. The observed log K_OC values were lower than the predicted log K_OC values for PBDEs (except for BDE28). The log K_OC values were higher than the predicted values for PCBs. A combination of sorption to colloids (10-98% for PBDEs and less than 25% for PCBs) and adsorption to BC was responsible for this observation.  相似文献   

"电纸"服务平台的研制     

方梅  余家树  吴利民 《地理空间信息》2011,9(1):71-72

从GIS平民化服务的角度,研制一种"电纸平台",即把纸质地图和电子地图的展现方式融为一体,使其优势互补,在老百姓应用和享受地理信息成果时,既能像纸质地图一样,一目了然,使用方便,又能具有电子地图海量数据库的支持,灵活方便展现、更新和网络化操作.  相似文献   

LA–ICP–MS U–Pb zircon geochronology, geochemistry and kinetics of the Wenquan ore-bearing granites from West Qinling, China     

Xiaofeng Cao  Xinbiao Lü  Shuzhen Yao  Wei Mei  Xiaoyan Zou  Chao Chen  Shentai Liu  Ping Zhang  Yuyun Su  Bin Zhang 《Ore Geology Reviews》2011,43(1):120-131

Many hydrothermal Cu–Mo–Au deposits related to granitoid intrusives were recently discovered in the West Qinling Orogenic Belt (WQOB). These deposits were mainly formed during the late Indosinian epoch (ca. 214 Ma), and the regional geological setting of Cu–Mo ore formation in WQOB during this epoch is poorly understood until now. This paper describes the geochronology and geochemistry of the Wenquan ore-bearing pluton, a composite granite body, to study the geologic background of magmatic emplacement and ore formation. The Mo mineralisation occurs at the contact between a fine-grained biotite monzogranite and a medium- to fine-grained porphyritic monzogranite. Zircon ²⁰⁶Pb/²³⁸U ages of 223 ± 3 Ma (biotite monzogranite) and 225 ± 3 Ma (porphyritic monzogranite) were obtained. Geochemical analyses show that the Wenquan pluton is a high-K calc-alkaline to shoshonite series rock with relatively high LREE and low HREE and a moderate to weak negative Eu anomaly. Relatively negative anomalies of Ba, Ti, P, Nb, Ta also exist. These results imply that the Wenquan pluton was emplaced during a transitional process (from collision to extension) between the Yangtze Craton and North China Craton. During the later Indosinian epoch, the East Qinling Orogenic Belt (EQOB) and WQOB had similar tectonic settings, and intensive magmatic activity and Mo mineralisation occurred. The EQOB was then involved in the Mesozoic subduction of the Pacific plate, and its subsequent tectonic evolution was different from that of the WQOB.  相似文献   

Geochemical Characters of Water Coproduced with Coalbed Gas and Shallow Groundwater in Liulin Coalfield of China     

YANG Mei  JU Yiwen  LIU Guijian  TONG Li  KANG Yu  HOU Quanlin 《《地质学报》英文版》2013,87(6):1690-1700

To reveal the geochemical characters of water coproduced with coalbed gas and shallow groundwater,water samples were collected from 12 wells of coalbed methane and 7 wells of shallow groundwater.The pH,CODMn,fCO2,total dissolved solids （TDS）,total hardness,and concentrations of metasilicic acid,sodium and kalium,calcium ion,magnesium ion,ammonium iron,bicarbonate ion,carbonate,chloride,sulfate ion,nitrate ion,fluoride,lithium,zinc,nickel,manganese,iron,boron,barium,etc.of the samples were measured.Research results showed the following：（1） Concentrations of TDS,chloride,fluoride,sodium and kalium,ammonium,iron,and barium in the water coproduced with coalbed gas exceeded the national standards of China; however,physical,chemical,and biological properties of shallow groundwater could meet the national standard.（2） The water produced from coalbed contained mainly Na-Cl·HCO3,with average TDS of 4588.5 ppm,whereas shallow groundwater contained a mixture of chemicals including Na.Mg.Ca-HCO3·SO4 and Na.Mg-HCO3·SO4,with average TDS of 663.8 ppm.（3） In general,it was observed that bicarbonate and sodium accumulated in a reducing environment and deeper system,while depletion of hydrogen ions and dissolution of sulfate,calcium,and magnesium occurred in a redox environment and shallow system.（4） Sodium and kalium,ammonium,chloride,and bicarbonate ions were the main ions found in the study area.  相似文献