一个具有下垫面温度耦合的大气环流的统计—动力模式     

陈英仪 《海洋预报》1992,(4)

本文从动力学定律出发,推导了一个线性的、具有下垫面温度耦合的大气环流的统计—动力模式,并用该模式对500hPa高度场及1000hPa温度场作1～30天的平均预报试验。模式的预报结果大大优于惯性预报,但耦合与不耦合的结果差别不大。  相似文献   

The emerging role of climate in post-smolt growth of Atlantic salmon   总被引：1，自引：1，他引：1  

Friedland  Kevin D.; Chaput  Gerald; MacLean  Julian C. 《ICES Journal of Marine Science》2005,62(7):1338-1349

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Storminess and vulnerability along the Atlantic coastlines of Europe: analysis of storm records and of a greenhouse gases induced climate scenario     

I. Lozano  R. J. N. Devoy  W. May  U. Andersen 《Marine Geology》2004,210(1-4):205-225

Identification of the distinctive circulation patterns of storminess on the Atlantic margin of Europe forms the main objective of this study; dealing with storm frequency, intensity and tracking. The climatology of the extratropical cyclones that affect this region has been examined for the period 1940–1998. Coastal meteorological data from Ireland to Spain have been linked to the cyclone history for the North Atlantic in the analysis of storm records for European coasts. The study examines the evolution in the occurrence of storms since the 1940s and also their relationship with the North Atlantic Oscillation (NAO). Results indicate a seasonal shift in the wind climate, with regionally more severe winters and calmer summers established. This pattern appears to be linked to a northward displacement in the main North Atlantic cyclone track.

An experiment with the ECHAM4 A-GCM at high resolution (T106) has also been used to model the effect of a greenhouse gases induced warming climate on the climatology of coastal storms in the region. The experiment consists of (1), a 30-year control time-slice representing present-day equivalent CO₂ concentrations and (2), a 30-year perturbed period corresponding to a time when the radiative forcing has doubled in terms of equivalent CO₂ concentrations. The boundary conditions have been obtained from an atmosphere-ocean coupled OA-GCM simulation at low horizontal resolution. An algorithm was developed to allow the identification of individual cyclone movements in selected coastal zones. For most of the northern part of the study region, covering Ireland and Scotland, results describe the establishment by ca. 2060 of a tendency for fewer but more intense storms.

The impacts of these changes in storminess for the vulnerability of European Atlantic coasts are considered. For low-lying, exposed and ‘soft’ sedimentary coasts, as in Ireland, these changes in storminess are likely to result in significant localised increases in coastal erosion.  相似文献   

Pressure prediction in the Bullwinkle Basin through petrophysics and flow modeling (Green Canyon 65, Gulf of Mexico)     

P.B. Flemings  J.A. Lupa   《Marine and Petroleum Geology》2004,21(10):1311-1322

Reservoir pressures within the Bullwinkle minibasin (Green Canyon 65, Gulf of Mexico continental slope) increase at a hydrostatic gradient whereas pressures predicted from porosity within mudstones bounding these reservoirs increase at a lithostatic gradient: they are equal at a depth 1/3 of the way down from the crest of the structure. Two- and three-dimensional steady-state flow models demonstrate that bowl-shaped structures will have lower pressures than equivalent two-dimensional structures and that if a low permeability salt layer underlies the basin, the pressure is reduced. We conclude that at Bullwinkle, pressure is reduced due to an underlying salt body and the bowl-shape of the basin. A geometric approach to predict sandstone pressure is to assume that the reservoir pressure equals the area-weighted average of the mudstone pressure. When the mudstone pressure gradient is constant, as at Bullwinkle, the reservoir pressure equals the mudstone pressure at the average depth (centroid) of the reservoir.  相似文献   

Palynological Evidence on Climate Changes in the East China Sea During Mid and Late Holocene     

李珍  王永吉  刘振夏  蓝东兆 《海洋通报(英文版)》2001,3(2)

The pollen analysis of DGKS9617 core in the East China Sea (covering about the last 6800 years) shows five obvious pollen assemblages and seven sub-assemblages. Combined with the sediment and the result of diatom analysis, the climate changes are reconstructed during the Middle and Late Holocene. Corresponding to the pollen assemblages, the climate shifts just as follows: Assemblage Ⅰ-Warm and Dry Stage, Assemblage Ⅱ-Cool and Humid Stage, Assemblage Ⅲ-Hot and Dry Stage (the mean annual temperature is 2～3 ℃ higher than that today ), Assemblage Ⅳ-Cool and Humid Stage, Assemblage Ⅴ-Wann and Dry Stage. The third stage is divided into three substages i.e. a slight colder and dry one, a slight wanner and humid one and a slight warmer and dry one. During the fifth stage, the climate becomes similar to that today with three warm substages and two cool substages.  相似文献   

The flow of Atlantic water to the North Icelandic Shelf and its relation to the drift of cod larvae   总被引：1，自引：0，他引：1  

Jonsson  Steingrimur; Valdimarsson  Hethinn 《ICES Journal of Marine Science》2005,62(7):1350-1359

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Filters for linear sea-wave prediction     

M.R. Belmont  J.M.K. Horwood  R.W.F. Thurley  J. Baker 《Ocean Engineering》2006,33(17-18):2332-2351

Deterministic sea-wave prediction (DSWP) models are appearing in the literature designed for quiescent interval prediction in marine applications dominated by large swell seas. The approach has focused upon spectral methods which are straightforward and intuitively attractive. However, such methods have the disadvantage that while the sea is aperiodic in nature, the standard discrete spectral processing techniques force an absolutely periodic structure onto the resulting sea surface prediction models. As it is the shape of the sea surface that is important in such applications, particularly near the end of the domain which is important, the standard windowing techniques used in signal processing work to reduce leakage artifacts cannot be employed. This has necessitated the use of end matching methods that can be both inconvenient and may reduce the fraction of the time for which legitimate predictions are available. As a result, an investigation has been undertaken of the use of finite impulse response prediction filters to provide the necessary dispersive phase shifting required in DSWP systems. The present work examines the theoretical basis for such filters and explores their properties together with their application to both long and short crested swell seas. It is shown that wide band forms of such filters are only convergent in the sense of distributions having both infinite duration impulse responses and asymptotically divergent first derivatives. However, appropriate band limitation can produce useful finite impulse responses allowing implementation via standard discrete convolution methods. It is demonstrated that despite the prediction filters having a non-causal impulse response such filters can be used in practice due to a combination of the asymmetric nature of the impulse response and the fundamental nature of the prediction process. The findings are confirmed against actual sea-wave data.  相似文献   

基于神经网络的平底结构砰击压力预报   总被引：1，自引：0，他引：1  

陈震  肖熙 《海洋工程》2005,23(2):26-31,41

对利用神经网络预报平底结构入水砰击压力的方法进行了探讨。首先利用仿真软件计算各种情况下平底结构入水所产生的砰击压力，以此形成训练神经网络的数据集。其次利用数据集对三层反馈式网络进行了训练，讨论了不同隐含层节点数对该非线性系统的拟合能力，并且对梯度下降法、动量修正法和基于优化的LM算法的有效性和精度进行了比较，最后得出了适合平底结构入水砰击系统的网络结构。  相似文献   

1999年以来台湾及邻近海域7.5级以上强震前的条带现象     

张年明  郑健志 《台湾海峡》2005,24(4):426-432

中国台湾地区地处欧亚板块与菲律宾海板块之间,地震活动频繁．本文报道了 我国台湾地区及其邻近海域1985～2002年间5．5级以上地震的条带内外频度比分 布,并着重研究了1999—2002年中发生的3次7．5级以上地震前的条带现象．其结 果表明:台湾地区近期发生的3次7．5级以上大地震前,5．5级以上地震呈条带分 布．这些条带符合条带内地震个数Nin≥6的条件,符合条带内、外频度比Nin／(Nin Nout)≥75％的条件,也符合条带长宽比大于5的要求,只是与板内地震条带相比,条 带的长度较短．  相似文献   

Capelin (Mallotus villosus) distribution and climate: a sea "canary" for marine ecosystem change     

Rose  G.A. 《ICES Journal of Marine Science》2005,62(7):1524-1530

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