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51.
从流体动力学基本方程出发 ,推导出近海定常环流的高程模式 ,由此高程模式利用有限差分法组成观测方程 ,从而按最小二乘间接平差法解算联合问题 ,最后联合T/P、ERS_2卫星测高和物理海洋观测数据 ,计算了东中国海 (北纬 2 2°～ 41° ,东经 116°～ 131°)的平均海面地形。 相似文献
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The flow patterns of Euro-Atlantic blocking events in winter are investigated by dividing the sector into three sub- regions： 60°-30°W （Greenland region）; 20°W-30°E [eastern Atlantic-Europe （EAE） region]; and 50°-90°E （Ural region）. It is shown that blocking events in winter are extremely frequent in the three sub-regions. Composite 500-mb geopotential height fields for intense and long-lived blocking events demonstrate that the blocking fields over Greenland and Ural regions exhibit southwest-northeast （SW-NE） and southeast-northwest （SE-NW） oriented dipole-type patterns, respectively, while the composite field over the EAE region exhibits an Ω-type pattern. The type of composite blocking pattern seems to be related to the position of the blocking region relative to the positive center of the climatological stationary wave （CSW） anomaly existing near 10°W.
The physical cause of why there are different composite blocking types in the three sub-regions is identified using a nonlinear multiscale interaction model. It is found that when the blocking event is in almost the same position as the positive CSW anomaly, the planetary-scale field can exhibit an Ω-type pattern due to the enhanced positive CSW anomaly. Neverthe- less, a SW-NE （SE-NW） oriented dipole-type block can occur due to the reduced positive CSW anomaly as it is farther in the west （east） of the positive CSW anomaly. The total fields of blocking in the three regions may exhibit a meandering flow comprised of several isolated anticyclonic and cyclonic vortices, which resembles the Berggren-Bolin-Rossby meandering jet type. 相似文献
The physical cause of why there are different composite blocking types in the three sub-regions is identified using a nonlinear multiscale interaction model. It is found that when the blocking event is in almost the same position as the positive CSW anomaly, the planetary-scale field can exhibit an Ω-type pattern due to the enhanced positive CSW anomaly. Neverthe- less, a SW-NE （SE-NW） oriented dipole-type block can occur due to the reduced positive CSW anomaly as it is farther in the west （east） of the positive CSW anomaly. The total fields of blocking in the three regions may exhibit a meandering flow comprised of several isolated anticyclonic and cyclonic vortices, which resembles the Berggren-Bolin-Rossby meandering jet type. 相似文献
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Diagnostic Study of Global Energy Cycle of the GRAPES Global Model in the Mixed Space-Time Domain 
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下载免费PDF全文 Some important diagnostic characteristics for a model’s physical background are reflected in the model’s energy transport, conversion, and cycle. Diagnosing the atmospheric energy cycle is a suitable way towards understanding and improving numerical models. In this study, formulations of the “Mixed Space-Time Domain”energy cycle are calculated and the roles of stationary and transient waves within the atmospheric energy cycle of the Global-Regional Assimilation and Prediction System （GRAPES） model are diagnosed and compared with the NCEP analysis data for July 2011. Contributions of the zonal-mean components of the energy cycle are investigated to explain the performance of numerical models. The results show that the GRAPES model has the capability to reproduce the main features of the global energy cycle as compared with the NCEP analysis. Zonal available potential energy （AZ） is converted into stationary eddy available potential energy （ASE） and transient eddy available potential energy （ATE）, and ASE and ATE have similar values. The nonlinear conversion between the two eddy energy terms is directed from the stationary to the transient. AZ becomes larger with increased forecast lead time, reflecting an enhancement of the meridional temperature gradient, which strengthens the zonal baroclinic processes and makes the conversion from AZ to eddy potential energy larger, especially for CAT （conversion from AZ to ATE）. The zonal kinetic energy （KZ） has a similar value to the sum of the stationary and transient eddy kinetic energy. Barotropic conversions are directed from eddy to zonal kinetic energy. The zonal conversion from AZ to KZ in GRAPES is around 1.5 times larger than in the NCEP analysis. The contributions of zonal energy cycle components show that transient eddy kinetic energy （KTE） is associated with the Southern Hemisphere subtropical jet and the conversion from KZ to KTE reduces in the upper tropopause near 30？S. The nonlinear barotropic conversion between stationary 相似文献
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为了在结构强震灾变过程模拟中正确反映结构参数的随机性并准确界定结构失效模式,提出一种平稳随机激励下随机结构非线性动力响应分析的简化方法.首先运用点估计法将复合非线性随机系统转化为一系列平稳随机激励下的确定性非线性结构,然后再应用成熟的等效线性化方法计算出平稳随机激励下非线性结构动力响应的各阶矩.文末进行了算例分析与验证... 相似文献
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提高地震信号的分辨率是地震勘探要解决的一项主要任务,而提高地震信号的信噪比是提高地震信号分辨率的先决条件。要提高地震资料的信噪比,需要去除地震资料中的相干噪声和随机噪声。本文介绍了平稳小波变换结合阈值压制面波干扰的方法,通过实际地震记录的处理证实了该方法的有效性。 相似文献
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Abstract The weakly nonlinear evolution of a free baroclinic wave in the presence of slightly supercritical, vertically sheared zonal flow and a forced stationary wave field that consists of a single zonal scale and an arbitrary number of meridional harmonics is examined within the context of the conventional two-layer model. The presence of the (planetary-scale) stationary wave introduces zonal variations in the supercriticality and is shown to alter the growth rate and asymptotic equilibrium of the (synoptic-scale) baroclinic wave via two distinct mechanisms: The first is due to the direct interaction of the stationary wave with the shorter synoptic wave (wave-wave mechanism), and the second is due to the interaction of the synoptic wave with that portion of the mean field that is corrected by the zonally rectified stationary wave fluxes (wave-mean mechanism). These mechanisms can oppose or augment each other depending on the amplitude and spatial structure of the stationary wave field. If the stationary wave field is confined primarily to the upper (lower) layer and consists of only the gravest cross-stream mode, conditions are favorable (unfavorable) for nonzero equilibrium of the free wave. In addition to the time dependent heat flux generated by baroclinic growth of the free wave, its interaction with a stationary wave field consisting of two or more meridional harmonics generates time dependent heat fluxes that vary with period of the free wave. However, if the stationary wave field contains several meridional harmonics of sufficiently large amplitude, the free baroclinic wave is destroyed. 相似文献
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????????????仯???????????LS??AR??????????????????????????????????ERP????????????????????в???????????????в????н??в??????????????AR??????ERP?????????ERP??????1??10????????????????????????????????? 相似文献