FY-4A/AGRI传感器波段平均太阳辐照度计算及不确定性分析     

白杰  王国杰  牛铮  邬明权 《气象科学》2020,40(4):520-526

传感器大气顶层波段平均太阳辐照度(Band-Averaged Extraterrestrial Solar Irradiance,BAESI)是表观反射率和星上辐亮度之间转换的重要因子,为了针对FY-4A/AGRI有关通道较为准确地计算这一数值,分别以韩国COMS/GOCI、美国GEOS-16/ABI、日本Himawari-8/9/AHI传感器为例,利用国际上常用的6条太阳光谱曲线与传感器光谱响应函数参与计算BAESI,并与各传感器BAESI标准值进行比较。结果表明,Kurucz计算结果平均绝对误差与均方根误差均最小,是最理想的太阳光谱曲线,此外,Kurucz计算值与各传感器各波段BAESI标准值的最大偏差均小于4.5%,最大偏差百分比及对应波段分别为-2.39%(GOCI-band3)、1.49%(ABI-band6)、4.28%(AHI-08-band6)、4.42%(AHI-09-band6)。因此选择Kurucz太阳光谱曲线参与计算FY-4A/AGRI传感器各波段BAESI值,给出相应结果,并分析了计算值的不确定性,解决了将表观反射率转换为辐射亮度的困难。  相似文献   

A proposed frequency spectrum for fully developed wind waves by revisiting P-M spectrum     

Shouhua Liu  Ning Jia  Changlong Guan 《中国海洋大学学报(英文版)》2011,10(4):331-335

It is generally believed that the equilibrium range of wind wave spectrum is in the form of the −4 rather than −5 power law. However, in the widely applied P-M spectrum the equilibrium range is given in the form of −5 power law. In the present paper, a spectrum for full development of wind waves is proposed using the form of the Neumann spectrum, but adopting the −4 power law for the equilibrium range. The proposed spectrum has been verified with NDBC buoy data and could be a substitute for the P-M spectrum.  相似文献   

高分辨率恒星光谱处理与元素丰度分析软件平台     

赵景昆  赵刚  陈玉琴 《天文研究与技术》2007,4(2):153-158

精确的元素丰度分析通常是建立在高分辨率光谱的基础上的。为了提高光谱数据的处理效率和能够以友好的界面来进行光谱处理与丰度分析,开发了一套软件平台。利用这个平台,可以对一维光谱进行自动化和交互式处理,可以计算丰度并进行丰度分析,可以将得到的丰度结果录入到数据库中,然后根据研究需要到数据库中进行查询和提取,生成丰度的分析图表。  相似文献   

河外星系ⅢZw35的OH　megamaser辐射谱的研究     

俞志尧 《中国天文和天体物理学报》1994,(3)

我们用ⅢＺｗ３５的流量密度函数，来拟合观测得到的ＯＨｍｅｇａｍａｓｅｒ辐射谱。ＯＨｍｅｇａｍａｓｅｒ斑点处在窄线区薄盘上，作旋转运动和径向膨胀运动。窄线区薄盘是侧向的。从理论上我们得到ＯＨｍｅｇａｍａｓｅｒ辐射流量密度．发现与其辐射谱中主峰和伴峰相对应的ＯＨｍｅｇａｍａｓｅｒ斑点处在窄线区薄盘的不同位置。  相似文献   

Directional Spectrum of Wind Waves: Part Ⅰ- Model and Derivation     

LIU Yuguang )  *  YAN Xiao-Hai )  SU Ming-Yang ) ) Physical Oceanography Laboratory  College of Marine Environment  Ocean University of China  Qingdao  P..R.China) Center for Remote Sensing  Graduate College of Marine Studies  University of Delaware  Newark  DE  USA) Oceanography Division  Naval Research Laboratory  Stennis Space Center  MS  USA 《中国海洋大学学报(英文版)》2003,2(1)

1　Introduction　Numerousinvestigationsondeepwaterwindwavespectrumhavebeen performed (Phillips ,195 8;Bretschneider,195 9;PiersonandMoscowitz ,196 4;Hasselmannetal.,1973;Donelanetal.,1985 ;Ban ner ,1990 ;Wenetal.,1999) .Ondimensionalground ,Phillips (195 8)suggestedthattheequilibriumfre quencyspectrumofwindwavesfordeepwatershouldbe proportionaltoω- 5,andthecorrespondingwavenumberspectrumshouldbe proportionaltok- 4,whereωistheangularfrequencyandkisthewavenumber.Forfully developedwindwaves…  相似文献   

Directional Spectrum of Wind Waves: Part Ⅱ- Comparison and Confirmation     

LIU Yuguang )  *  YAN Xiao-Hai )  SU Ming-Yang ) ) Physical Oceanography Laboratory  College of Marine Environment  Ocean University of China  Qingdao  P..R.China) Center for Remote Sensing  Graduate College of Marine Studies  University of Delaware  Newark  DE  USA ) Oceanography Division  Naval Research Laboratory  Stennis Space Center  MS  USA 《中国海洋大学学报(英文版)》2003,2(1)

1　Introduction1.1　Proposed ModelonDirectionalFrequencySpec trum　ThisisthePartⅡofthetwo papersetondirection alspectraofwindwaves.Anewmodelonthedirec tionalspectrumofwindwavesfordeepwaterispro posedbasedonthestatisticsofwindwavesinthePartⅠ .Substituting (4 5 )ofPartⅠinto (4 0 )andaddingapeak enhancementitemγΓ,weobtainS(ω ,) =0 .0 0 93αaαwD( ,k) ωpω2 ξ- 4g2ω5×exp - 2 ξ+14[bωp +(1-b)ωp]4ω4 γΓ. (1)Here ,αaisthewaveagefactorofspectralcoefficientdefinedbyαa = ω0 .55…  相似文献   

湖北省荆江大堤沿堤地基土的分类特征     

胡坚  张柯  曾心传 《大地测量与地球动力学》1993,(4)

利用脉动测振方法对荆江大堤堤面沿线土层进行了实测研究,并对实测记录进行了傅氏谱分析。结果表明,沿堤土层绝大部分属于二类土地基,但有若干堤段土层属于由松散的粉、细砂所构成的三类土地基,且饱和程度非常高,有产生管涌和地震动液化的可能,应予特别注意。  相似文献   

A theory of spectral analysis based on the characteristic property of a linear dynamic system   总被引：3，自引：1，他引：2  

M. Kumazawa  Y. Imanishi  Y. Fukao  M. Furumoto  A. Yamamoto 《Geophysical Journal International》1990,101(3):613-630

  相似文献   

Is a chaotic multi‐fractal approach for rainfall possible?     

Bellie Sivakumar 《水文研究》2001,15(6):943-955

An Erratum has been published for this article in Hydrological Processes 15 (12) 2001, 2381–2382. Applications of the ideas gained from fractal theory to characterize rainfall have been one of the most exciting areas of research in recent times. The studies conducted thus far have nearly unanimously yielded positive evidence regarding the existence of fractal behaviour in rainfall. The studies also revealed the insufficiency of the mono‐fractal approaches to characterizing the rainfall process in time and space and, hence, the necessity for multi‐fractal approaches. The assumption behind multi‐fractal approaches for rainfall is that the variability of the rainfall process could be directly modelled as a stochastic (or random) turbulent cascade process, since such stochastic cascade processes were found to generically yield multi‐fractals. However, it has been observed recently that multi‐fractal approaches might provide positive evidence of a multi‐fractal nature not only in stochastic processes but also in, for example, chaotic processes. The purpose of the present study is to investigate the presence of both chaotic and fractal behaviours in the rainfall process to consider the possibility of using a chaotic multi‐fractal approach for rainfall characterization. For this purpose, daily rainfall data observed at the Leaf River basin in Mississippi are studied, and only temporal analysis is carried out. The autocorrelation function, the power spectrum, the empirical probability distribution function, and the statistical moment scaling function are used as indicators to investigate the presence of fractal, whereas the presence of chaos is investigated by employing the correlation dimension method. The results from the fractal identification methods indicate that the rainfall data exhibit multi‐fractal behaviour. The correlation dimension method yields a low dimension, suggesting the presence of chaotic behaviour. The existence of both multi‐fractal and chaotic behaviours in the rainfall data suggests the possibility of a chaotic multi‐fractal approach for rainfall characterization. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

GENERAL THEORY FOR APPARENT ENERGY DISTRIBUTION OF SEA WAVES     

吴克俭  孙孚 《中国海洋湖沼学报》1997,15(4):322-331

lwrRODUcrIONSeawavesarerecognindasacrucialfaCtorinengineeringandoffshorestruCturede-signsandconstitutCanimPoftantpartintheoreticalstudiesandapplicati0ns.TocopewiththecomPlexityofseawaves,alinearrandomwaveshomogeneousandstationarythe-oryisintrodutalwhereintwomodeIsdescribetheoonnsurfaeedisplacement.Inthefirstone,thesurfaeedisplaerentchangingwithlocationandtheisexpnssedingeneralitalFouriertransform,wherethefrequencyspeCtrumE(co)andwavenumberspodrumEoocanbedefined.Theotherwavemodelisbasedo…  相似文献