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本文进一步对旋转正压大气中的包络Rossby孤立波进行了研究,结果发现当Rossby波的波数m(m为纬向波数)满足1≤m≤2时,旋转正压大气中才存在包络Rossby孤立波,并且只有m=2的包络Rossby孤立波才具有阻塞高压的结构。我们还对这种m=2的包络Rossby孤立波随纬度变化的持续性进行了计算,得到了许多结果。 相似文献
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铝土矿床的包心构造,即粘土岩层包裹铝土矿体,是腐植酸长期分解土壤硅酸盐,而导致土壤剖面的垂直分层。具备垂直渗水系统的地形,如岩溶洼地、平顶山丘,是成矿的先决条件之一。铝岩系是一套陆相地层,夹在地层剖面的基底岩层风化侵蚀面之上,和其上发育植被的沉积间断面之下。铝土矿是陆上成矿,是植物化学风化残积矿床。 相似文献
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J. M. Huthnance 《地球物理与天体物理流体动力学》2013,107(1-3):81-106
Abstract The subject is reviewed from the viewpoints of theory, internal tide and wave structure and their implications. A wider theoretical context suggests scope for further investigation of natural or nearly-trapped forms above the inertial frequency. Although internal tides in many locations are observed to have first-mode vertical structure, higher modes are seen offshore from shallow shelf-break forcing and for particular Froude numbers, and may be expected locally near generation. Bottom intensification is often observed where the sea floor matches the characteristic slope. Solitons form from internal tides of large amplitude or at large changes of depth. Internal tides and solitons are observed also at many sills and in straits, and to intensify in canyons. Non-linear effects of the waves, especially solitons, include the conveyance of water, nutrients, ‘‘mixing potential'’ etc. away from their source to other locations, and the generation of mean currents. The waves transfer energy and possibly heat between the ocean and shelf, may be a source of medium frequency waves on the shelf (periods of minutes) and can contribute to interior mixing and overturning, bottom stirring and sediment movement. 相似文献
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River plume front-generated internal solitons play an important role in the interaction between the plume and coastal waters. The internal solitons drive a non-harmonic velocity field, resulting in a horizontal transport that carries plume water seaward and redistributes nutrients and sediments. In this study, we present observations of internal solitons generated at the Columbia River plume front that separates the new, tidal plume, older plume and coastal waters. Scale analyses suggest that the plume front-generated internal solitons are highly non-linear waves, and their dynamic properties do not conform to any weakly non-linear theory. Thus, a high-order Korteweg–de Vries (KdV) theory is used to analyze the internal solitons. The comparison between theoretical values and cruise data shows that the high-order KdV model is much better than the weakly non-linear theories for prediction of the soliton dynamic parameters. Based on the model, we develop theoretical and numerical solutions of the soliton-induced upper layer horizontal transport and Lagrangian water parcel transport distance, which shows that the water particle drift, during the internal soliton passage, is as far as 1 km, and demonstrates the role of the internal solitons on the exchange between the plume and ambient coastal water. Energy fluxes caused by the internal solitons are estimated using the high-order KdV theory. The leading soliton fluxes 2.0×103 W m−1 per unit crest length, and carries energy of 4.2×105 J m−1. The total energy carried by the eight internal solitons is 1.6×106 J m−1, about 70% of the total frontal energy. 相似文献
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本文扼要介绍了灰色系统的基本理论、建模方法和检验精度的分析方法。并以四平市地下水动态特征为例,建立GM(1,1)包络模型,进行了地下水位拟合和外推预报。结果表明,GM(1,1)模型计算简单,是一种实用的预报方法,预报结果比较可靠。 相似文献
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本文发展了一种单台检测低频地震事件的方法,并用其检测2008年汶川I Ms8.0地震、2013年芦山M。7.0地震震前的低频事件。使用汶JiI地震、芦山地震前周边的宽频带台站数月的垂直向连续波形,经过2~8 Hz带通滤波、窗长为10 S的包络平滑、窗长为20 rain的中值滤波,去除近场天然地震及远场大震与低频噪声的影响后,发现这两个大地震前有少数台站在连续数天的时间内,出现持续时间长(数十分钟到数小时)、包络中值明显大于背景噪声的现象,其波形记录及包络特征与非火山震颤(NVT)的波形记录及包络特征具有较好的相似性,我们认为这是汶川地震和芦山地震前的疑似慢地震事件。初步应用表明,本文所用的方法对于从宽频带连续波形资料中提取NVT信号是可行的。 相似文献