带乘性噪声系统双滤器平滑及反褶积算法     

张文林  褚东升  王昕 《中国海洋大学学报(自然科学版)》1999,(3)

在带乘性噪声系统（ＳＭＮ）间接平滑算法的基础上,通过构造一种新的ＳＭＮ逆向信息滤波算法,建立了ＳＭＮ的双滤器平滑和反褶积算法;为解决ＳＭＮ最优估计问题提供了新的方法。  相似文献   

POM对南海海温年变化的模拟   总被引：7，自引：3，他引：4  

钱永甫  王谦谦  朱伯承 《大气科学》2000,24(3):373-380

将Internet上的美国普林斯顿大学海洋模式（POM）改造为能够模拟南海（SCS）海洋要素的模式。在POM中,加入了真实的南海海底地形,使用了误差扣除的压力梯度计算方法,引进了海气界面上热通量计算方案,增加了前置和后置处理程序,使模式能够根据研究目的,模拟和预测海洋要素的时间变化及空间分布。利用改造后的POM模拟了南海海温的年变化,并进行了详细的分析和讨论。结果表明,改造后的POM可较好地模拟出南海海温的年变化特征,其模拟性能随季节而有不同。文中对模拟中存在的不足之处也进行了讨论。  相似文献   

Characteristics of annual laminae gray level variations in a stalagmite from Shihua Cave, Beijing and its climatic significance (II)   总被引：3，自引：0，他引：3  

Lü Jinpo 《中国科学D辑(英文版)》2000,43(5):521-533

The annual laminae gray level variations in the stalagmite TS9501 of Shihua Cave, Beijing are studied in detail. The environmental factors influencing the laminae gray level are also analyzed. The following conditions may be necessary to the study on the lamina gray level. A) The seasonal differences of climate in the studied area are strong. B) The cave has a rapid and simple hydrological connection with the surface, such that the gray level variation is great; therefore, climatic changes can be more clearly recorded in a stalagmite. C) No water from other sources due to lateral flow adds to the seepage over the cave. D) There are more organic impurities than inorganic ones, whose content changes distinctly with time in the sample. By comparison with the modern instrumental climate records, it was found that the gray level of laminae is mainly related to the air temperature, especially the summer mean temperature. Therefore, the gray level can be used as a proxy of the air temperature. The variation of the lamina gray level also represents the oscillation of Indian summer monsoon as identified in the modern climate records. The variability of the temperature in Beijing area over the last 1 ka is reconstructed. The results show that there are several cold periods corresponding to historical records. An important phenomenon is noticed that the climatic pattern before about 1400AD is different from that after about 1400AD. In Beijing area, before about 1400AD, low amplitude and high frequency temperature oscillations dominated the signal. The climate pattern is warm-dry and cold-wet. After about 1400AD, both the temperature and rainfall varied synchronously, temperature oscillated strongly and the Little Ice Age occurred. The climate pattern is cold-dry and warm-wet. This transition of the climate pattern is also observed in other worldwide paleoclimatic records, demonstrating that there was a global climate event at about 1400AD.  相似文献   

上海中华地学会和《地学季刊》     

禇绍唐 《地理研究》1984,3(3):104-110

二十世纪初,是我国地理学发展的更替时期,一方面记述性的旧地理学逐渐被淘汰,另一方面探寻地理事象因果规律的新地理学正在成长。为了积极推动新地理学的发展,三十年代初在上海从事地理教学、研究及编辑出版的人士便发起成立《中华地学会》,成为继中国地学会(1909年成立)之后我国第二个地理学术组织。  相似文献   

Comparison between relay propagation and direct propagation of Gaussian—Schell-model beam in turbulent atmosphere along a slant path     

储修祥  刘泽金  吴毅 《海洋学报(英文版)》2010,29(9)

The relay propagation of Gaussian--Schell-model in turbulent atmosphere along a slant path is studied in this paper. Based on the extended Huygens--Fresnel principle and a quadratic approximation, an analytical formula of average intensity for Gaussian--Schell-model beams in turbulent atmosphere along a slant path is derived, and some special cases are discussed. From the study and the comparison with the direct propagation, we can see that the relay propagation has an advantage over the direct propagation. When the altitude of the target is low, the peak intensity of relay propagation is much larger than that of direct propagation. However, because of the limitation of the relay system aperture for relay propagation and the variation of coherence length for direct propagation, the difference in peak intensity between the two propagations decreases with the increase of the target altitude.  相似文献   

北京城区气温变化特征   总被引：1，自引：0，他引：1  

胡保昆  窦以文  储伟 《气象科技》2014,42(5):852-855

利用1975—2012年朝阳、海淀和丰台气象站年平均气温、最高和最低气温及降水资料研究北京城区气温变化特征。结果表明:1北京气温近40年来增温显著,年平均、最高和最低气温增温率分别为0.445、0.33、0.5℃/10a。北京近年来的增温以20世纪90年代和21世纪初最为显著。2用M-K方法检验北京气温存在跃变现象,平均、最高和最低气温的跃变时间分别为1992、1992、1991年。3跃变后比跃变前年平均最低气温上升幅度最大,达1.1℃;平均气温次之达1.0℃;最高气温上升达0.8℃。4跃变后比跃变前高温日数增加,冷的日数减少,即跃变后气温达到更暖阶段。降水在跃变后比跃变前减少,即降水和气温变化呈反位相向分布。  相似文献   

克氏原鳌虾LDH同工酶的组织特异性研究     

母昌考  张引  戴余军  黄孝湘  徐东生  吕帮玉 《海洋湖沼通报》2008,(3)

以克氏原螯虾为材料,采用聚丙烯酰胺凝胶电泳方法,分析了肌肉、眼球、肝胰腺和心脏4种组织和器官中乳酸脱氢酶(LDH)同工酶的表达情况.结果发现,眼球中出现Ldh-5和Ldh-6 2条酶带,肌肉中出现Ldh-1、Ldh-2、Ldh-3、Ldh-4、Ldh-5共5条酶带,肝胰腺中只出现Ldh-6 1条酶带,心脏中出现Ldh-3和Ldh-5共2条带.在这些检测到的酶带中,肌肉中Ldh-5活性最强,染色最深.实验结果表明,不同组织中LDH的同工酶的表达存在差异,表现出明显的组织特异性.  相似文献   

蔬果农产品可追溯物流信息系统的构建与应用   总被引：6，自引：1，他引：5  

屈晓晖  庄大方  邱冬生 《地球信息科学学报》2008,10(5):615-622

蔬果农产品是人们生活的必需品,其安全问题关系着国计民生。北京2008年奥运会的食品安全问题引起各级政府的普遍关注。本文将蔬果物流过程与可追溯相结合,提出了可追溯物流的概念,并从技术层面对物流过程可追溯的实施进行了分析,提出了一个利用IC卡记录、存储蔬果物流信息的可追溯信息传递方案,并对系统原型进行了构建,最后以北京市数据为基础对系统进行了应用。实践证明,利用GIS技术辅助实现蔬果农产品物流过程的可追溯方案是高效可行的,它为我国建立可靠实用的质量跟踪和可追溯蔬果物流体系提供了一个新的思路。  相似文献   

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金涛勇  李建成  邢乐林  褚永海 《大地测量与地球动力学》2008,28(3):92-95

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Determination of the Current System on Isopycnal Surface Between Mindanao and New Guinea from GDEM   总被引：1，自引：0，他引：1  

Peter C Chu 《中国海洋湖沼学报》2003,21(3):193-213

1 .INTRODUCTIONThewesternequatorialPacific ,particularlythesouthernmostPhilippineSea ,wascalled“watermasscrossroads”byFineetal.(1 994 )duetotheconfluencethereofseveralwatermassesfromhigherlatitudesofbothhemispheres (Wyrtki,1 96 1 ;Fineetal.,1 994 ) .Fineetal.(1 994 )de picted (Fig .1 )majorcurrentsintheIndonesianregion .AfterencounteringthewesternboundaryalongthePhilippinecoast,theNorthEquatorialCur rent (NEC)bifurcatesintothenorthwardflowingKuroshioandthesouthwardflowingMindanao…  相似文献