五种短期气候预测统计模型的研制     

许炳南 《贵州气象》2001,25(2):5-9

根据“九五”贵州短期气候预测研究课题总体安排，研制了一套短期气候预测模型，并建立了5种统计模型；逐步回归预报模型、多因子综合相关相似预报模型、500hPa环流相似预报模型、北太平洋海温相似预报模型、贵州分区RT在归预报模型。各预报模型的建模样本年限为1957－1996年，独立试报期为1997年及其以后年份。每一个预报模型均可在每月作出其后6个月的逐月雨量和平均气温预报、其后3个季度的季雨量及气温预报气候灾害指数预报。经1997－2000年试报表明，各项报模型对预报较以往公开发布的月雨量和月平均气温业务预报无论在趋势预报评分或技巧评分上均有明显提高。  相似文献   

递归相似及其在海温演化中的应用     

周亚军  朱姝 《干旱气象》1996,(1)

对刘桂馥（１９９５）［１］提出的递归相似进行计算机编程，并用此法作了特殊个例分析。与统计概念不同，文中的跃变定义为前Ｒ个数据不能完全表达当前时刻值的程度。通过对百余年（１８５６—１９９１年）南北半球太平洋、大西洋和印度洋季海温距平的递归相似分析发现：在适当分辨率下，当６≤Ｒ≤２０时跃变具有准１０年周期；当２５≤Ｒ≤８０时跃变主要出现在１８９０年左右、１９１０年左右和１９３０年左右，５０—７０年代为跃变的群发期  相似文献   

南沙海域近海层大气湍流结构及输送特征研究   总被引：21，自引：0，他引：21       下载免费PDF全文

马耀明  王介民  刘巍  张庆荣  麦波强 《大气科学》1997,21(3):357-365

本文根据南沙群岛渚碧礁的一次大气湍流观测资料，分析研究南沙海域的湍流热通量输送、方差相似性、风速各分量谱、温度谱及各湍流通量协谱等大气湍流结构和输送特征，并与陆地下垫面上的结果作了比较，得到了一些有关南沙海域大气湍流输送及湍流结构的新认识。  相似文献   

Experiment and Simulation for Articulated Lifting Subsystem of 1000 m Deep Sea Mining System     

冯雅丽张文明  冯福璋徐妍 《中国海洋工程》2007,21(3):525-532

The experiment system of 1000 m deep sea mining system is built up with the similarity theory.Sine mechanism is used to simulate mining ship to generate lateral shock excitation by ocean wave.Simulation and experiment of spherical joint connecting deep sea mining system has been done in band six marine conditions.The results indicate that the moment of spherical joint connecting deep sea mining is smaller than that of the thread connected ones,the lifting pipe of spherical joint is "flexible pipe".The flexural torque of the articulated lifting pipe system in pump and buffer is generally periodic variation with some irregularity,the value is stable on 60 N·S,and it is obviously smaller than that of the fixed lifting pipe system;The total displacement exhibits cyclic variation pattern,and the periodicity of them is longer than that of sea current.The results of experiment and simulation are basically consistent.And the analysis in the paper offers theoretical foundation of 1000 m deep sea mining system in China.  相似文献   

耐低温杜氏藻突变株的诱变和鉴定     

周韬  刘广发  黄瑞芳  陈昱 《台湾海峡》2006,25(4):498-502

采用紫外线辐射的方法对巴氏杜氏藻(Dunaliella bardawil)进行诱变.经过低温(5±1℃)筛选,得到一耐低温的突变株,命名为Dunaliella bardawilvar.L-5 Zhou&Liu(简称L-5).研究表明,在5±1℃光照培养箱中光强1 100 lx培养57 d,L-5仍继续处于对数生长期,而对照组早已进入生长平衡期,此时L-5藻细胞密度为对照的2.59倍.蛋白质SDS-PAGE电泳表明,在大约36和158 kDa处L-5比对照各多出一条新的蛋白带,同时在大约27和29 kDa处L-5出现比对照高得多的两条蛋白表达带.RAPD分析表明两者的遗传相似系数为0.768.由此作者初步认为L-5确为一耐低温的杜氏藻突变株.  相似文献   

Discrepancy and Applicability of Various Similarity Functions in Flux Calculations Under Stable Conditions     

GUO Xiaofeng  ZHANG Hongsheng  CAI Xuhui  KANG Ling  LI Wanbiao  DU Jinlin 《大气科学进展》2007,24(4):644-654

Based on data obtained during the Hualhe River Basin Experiment （HUBEX） in 1999, this study intends to detect the quantitative discrepancies in the momentum （τ0）, sensible heat （H0） and latent heat （E0） fluxes among six sets of similarity functions with the aerodynamic method. It also aims to clarify the applicability of the functions under stable conditions. The relative discrepancy was studied with the normalized transfer coefficients for τ0, H0 and E0, namely CD, CH and CQ, respectively. Except for one set of functions that adopted a rather small von Kármán＇s constant （0.365）, the relative discrepancy in τ0 among the other functions was less than 10%, while that in H0（E0） sometimes reached 25% when the bulk Richardson number （R/B） was less than 0.07. The absolute discrepancy in the fluxes was studied with statistical computations. Among the six sets of functions, the discrepancy in τ0, H0 and E0 sometimes reached 0.03 kg m^-1 s^-2, 4 W m^-2 and 10 W m^-2, respectively, and the discrepancy in the energy balance ratio sometimes exceeded 0.1. Furthermore, when RiB exceeded the critical value （Ric） for a specific set of functions, no fluxes could be derived with the functions. It is therefore suggested that RiB be compared with Ric before computing the fluxes if RiB is less than Ric. Finally, two sets of nonlinear similarity functions are recommended, due to their unlimited applicability in terms of RiB.  相似文献   

Pattern based map comparisons   总被引：5，自引：0，他引：5  

Roger White 《Journal of Geographical Systems》2006,8(2):145-164

Map comparison techniques based on a pixel-by-pixel comparison are useful for many purposes, but fail to reveal important aspects of map similarities and differences. In contrast, pattern based map comparison techniques address the question of structural similarity, although with these approaches the comparison problem becomes open ended, since there is an unlimited number of ways to characterise a pattern. Two types of pattern based technique are used here to analyse the test sets of maps. The first, a fuzzy polygon based matching technique, focuses on the meso-scale aspects of pattern. It is based on the areal intersection of land use polygons on the two maps being compared. The areal intersection, areal complement, and polygon size values are fuzzified into an appropriate set of categories, a set of fuzzy inference rules is applied to derive memberships in local matching categories, and finally the local matching category memberships are defuzzified to yield local matching values for each land use polygon on the reference map. The second approach, fractal analysis, captures macro-scale or global qualities of the maps. Two measures are calculated here: the radial dimension and the cluster size—frequency dimension. The polygon matching approach provides only limited insight when applied to the case of the map set representing differences in classification. It proves much more effective when applied to the problem of change detection, revealing areas where the pattern has changed and giving local measures of the degree of change. The approach is particularly useful in the case where there is a considerable degree of random change at the pixel level, as changes in the underlying pattern are extracted from the noise, while pixel based approaches largely detect the noise.  相似文献   

Improving automatic location procedure by waveform similarity analysis: An application in the South Western Alps (Italy)     

M. Massa  G. Ferretti  C. Eva 《Physics of the Earth and Planetary Interiors》2006,154(1):18-29

The accuracy of automatic procedures for locating earthquakes is influenced by several factors such as errors in picking seismic phases, network geometry, modeling errors and velocity model uncertainties. The main purpose of this work is to improve the performances of the automatic procedure employed for the “quasi-real-time” location of seismic events in North Western Italy by developing a procedure based on a waveform similarity analysis and by using only one seismic station.To detect “earthquake families” a cross-correlation technique was applied to a data set of seismic waveforms recorded in the period 1985-2002, in a small test area (1600 km²) located in the South Western Alps (Italy). Normalized cross-correlation matrices were calculated using about 2700 seismic events, selected on the basis of the signal to noise ratio, manually picked and located by using the Hypoellipse code. The waveform similarity analysis, based on the bridging technique, allowed grouping about 65% of the selected events into 80 earthquake families (multiplets) located inside the area considered. For each earthquake family a master event is selected, manually re-picked and re-located by using Hypoellipse code. Having chosen a reference station (STV) on the basis of the completeness of the available data set, an automatic procedure has been developed with the aim of cross-correlating new seismic recordings (automatically picked) to the waveforms of the events belonging to the detected families. If the new event is proved to belong to a family (on the basis of the cross-correlation values), its hypocenter co-ordinates are defined by the location of the master event of the associated family. The performance of the proposed procedure is tested and demonstrated using a data set of 104 selected earthquakes recorded in the period January 2003-June 2004 and located in the test area. The automatic procedure is able to locate, associating events with the multiplets detected by the waveform similarity analysis, about 50% of the test events, almost independently of the accuracy of the automatic phase picker and without the biasing of the network geometry and of the velocity model uncertainties.  相似文献   

基于理想分形规则扩展的地图曲线模拟方法研究     

龙毅  李雯静 《测绘信息与工程》2004,29(2):1-4

针对地图目标中许多线状要素具有典型统计分形特征的性质,探讨了在理想分形规则基础上通过增加随机因子,从而根据分维数反过来模拟构建地图曲线的方法.  相似文献   

探地雷达物理模拟相似性准则及监测油气污染试验     

曾昭发  薛建  王者江  田钢  翁爱华 《吉林大学学报(地球科学版)》1998,(4)

利用探地雷达研究油气污染问题是探地雷达应用研究的前沿课题之一。在推导雷达波模型实验的相似性准则的基础上,制作了砂质模型,并以原油为污染材料进行了探地雷达监测油气污染的模型实验。证明探地雷达方法能有效地解决油气污染的范围和油气污染的强度问题。同时为开展下一步实验和野外工作提供了指导。  相似文献