共查询到20条相似文献，搜索用时 62 毫秒
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海岛岸线标志海岛的位置与大小,是海岛重要的自然要素。文章收集了1973—2015年间共5期遥感数据,结合现场调查典型岸段的影像与位置信息,提取福建海坛岛岸线并分析其近40余年的演变特征。结果表明,海坛岛岸线类型包括人工岸线、基岩岸线、砂质岸线与红土岸线等4类,岸线的变迁主要体现在垂直于海岸方向的进退与岸线长度的变化,人类活动对岸线变迁产生显著影响。从维护海岸安全和合理开发利用海岸的角度出发,结合海坛岛不同类型岸线的演变特征,提出海岸保护及开发利用的建议。 相似文献
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我国多次海岛数量普查因界定标准不一而结果相差巨大,为了满足海洋主管部门对海岛的管理要求,亟需研究合理的方法界定海岛数量。利用高分辨率遥感影像解译嵊泗县海岛2 875个,以分形理论讨论海岛数量与海岛面积、海岛间距的关联。结果表明,嵊泗县50%的海岛面积小于50 m~2或岛间距不足6 m,海岛数量与界定标准间呈分维数先增大后稳定的变维分形特征,分维数在220 m~2和28.5 m之后稳定在1.80和2.25。以200~500 m~2为界区分大小岛,小岛数量和海岛间距也存在变维分形特征,且分维数在间距大于50 m后趋于稳定。故嵊泗海岛最佳界定方法为以220 m~2筛选出计数海岛后再补充间距大于50 m的较小海岛,该方法下界定嵊泗海岛681个。 相似文献
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我国现有的海岛基础地理数据过于陈旧,失去了时效性,难以满足海岛开发、保护与管理工作的迫切需求.根据908专项浙江省海岛现场调查和遥感调查资料,并与历史资料进行比对和印证,对舟山群岛基本地理特征进行了统计和专题图制作,并对其变化进行了分析.研究表明,历次海岛调查工作所得舟山群岛的海岛数量、面积和岸线长度均有差异,原因有三:其一,海岛的定义和界定标准不同;其二,调查手段和资料精度不同;其三,围垦建坝等活动导致海岛合并、灭失或注销.至2008年底,舟山群岛拥有海岛1800个(其中有居民岛141个),总面积1299.4 k㎡,岸线总长2386.6 km.相对于1994年调查结果,新确认海岛500个(包括微型岛194个),灭失海岛83个,净增海岛数417个. 相似文献
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本研究采用IKONOS遥感图像,选取波谱特征区,通过区域像元统计并计算各波段权重系数,将影像进行波谱归一化处理,使归一化的影像岛陆与海水特征更明显。在此基础上,采用最大类间方差法确定最佳分割阈值,对归一化的影像进行二值化,从而提取海岛岸线。该方法采用特征曲线法进行水陆分离,得到的二值图像保持了原图的有效边缘,采用二值形态学提取的海岸线连续可靠、信噪比高。结果表明,该方法简单、快速,能有效提取海岸线,具有实用价值。 相似文献
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营口市位于辽宁省的中南部，面对渤海的辽东湾，背依鞍山市平原丘陵，东邻辽东崇山峻岭，西接盘锦市沿海平原，有辽河蜿蜒人海，海岸线绵延曲折。由于受海洋、河流的影响．营口市四季分明，气候宜人，蕴藏着丰富的滨海旅游资源，海蚀景观、地质珍迹、人文景观等资源各显异彩；尤其是海水浴场，条件极为优越，与国际上一流的海水浴场相比．毫不逊色，在某些特征上还稍胜一筹。 相似文献
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A. P. Tolstosheev 《Physical Oceanography》2009,19(6):358-365
A method for the estimation of the results of reconstruction of the trajectories of drifting buoys is proposed. It is based
on the comparison of the estimates of power spectral densities for the components of current velocity computed according to
three data sets: the data set of the coordinates of a drifting buoy with a built-in GPS receiver, the data set of coordinates formed on the basis of the first set but with data missing and observational errors
corresponding to the actual trajectory measurements by the Argos satellite location and data collection system by the Doppler method, and the data set of coordinates obtained as a result
of interpolation of the second set. As an example, we consider the procedure of realization of the proposed method and demonstrate
the efficiency of its application for the improvement of the reliability of reconstruction of the trajectories of drifting
buoys. 相似文献
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I. E. Timchenko A. A. Primalenny V. D. Yarin E. F. Vasechkina E. M. Igumnova 《Physical Oceanography》2001,11(4):367-378
We use many-year archival observations of hydrologic and hydrobiologic state of the Sea of Azov for the identification of
the structure of a model of its ecosystem. The ecosystem model, supplemented with expert estimates of bioresource consumption
(fish reserve), contamination level, and possible ecologic fines for violation of the sea natural state, is formalized by
the method of system dynamics. Hereat, the major part of influence functions is found in terms of observational data with
application of self-organization algorithms. We also present the results of simulated experiments with the model of the ecosystem,
which enable us to analyse scenarios of its behaviour under the influence of various external factors (wind, river discharge,
water exchange with the Black Sea, etc.).
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
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An attempt has been made to estimate the fishery potentials of the EEZ of India on the basis of data on primary and secondary production. The total column primary production and zooplankton production have been calculated to be 265·9 and 9 million tonnes of carbon per year, respectively. From these values the fishery potential has been estimated as 2·5 million tonnes per year. To this, if we add the estimated demersal fish catch, being 1·2 million tonnes per year, the total potential yield comes to 3·7 million tonnes per year. Since the present average total catch is about 1·6 million tonnes in a year, the fish catch could be doubled. 相似文献
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天然气水合物地球化学特征 总被引：4，自引：0，他引：4
天然气水合物是在低温、高压以及有足够气体供应条件下形成的一种天然气(主要为甲烷)与水组成的似冰状固态化合物。天然气水合物中包含的甲烷碳是全球甲烷资源的重要组成部分,是一种数量巨大的潜在能源[1]。而且由于甲烷的温室效应,天然气水合物分解释放的甲烷进入大气中会严重 相似文献
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1992年，联合国21世纪议程提出了综合管理的概念，并认为它是海岸管理的最重要目标，而海岸管理的目的就是改进业已存在的管理实践的效率和效果。在21世纪议程的实施过程中，沿海国家面临着巨大的困难，即：为了使综合管理在实践中具有可操作性而建立适合的政府机构。韩国正是在国家范围和次一级区域进行这项工作的实验场所。这项工作的最重要成就是在1996年成立了具有综合协调各涉海部门职能的韩国海洋事务与渔业部（MOMAF）。这篇文章的内容主要来自于这些观察，即韩国政府为建立海岸带综合机制而进行了各种努力，特别是1992年联合国环发大会召开后到1997年初海洋事务与渔业部成立了海岸带管理处这段时间里开展的各种工作，文章重点在于评价在建立海岸带综合机制的过程中综合的概念是如何被应用并被挑战的。文章提出了在东亚地区沿海国家开展合作的可能区域的建议。 相似文献
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The analysis of the structure of the cryolithozone, facies, and thicknesses of the Quaternary sediments and the results of the physicochemical mathematical modeling of the modern shelf of the western part of the Laptev Sea support the influence of the Late Pleistocene glaciations on the heat conditions and the distribution of the permafrost in the area. A ～200-m thick glacier formed under aerial conditions from atmospheric precipitation represented the metamorphosed snow cover. According to the modeling, the long-living (from 60?50 to 10?4 ky) glacier reduced the thickness of the permafrost rocks in the reviewed shelf area for 280–360 m. The Holocene marine transgression additionally decreased the thickness from 50–140 m on the inner shelf to 220–350 m on the outer shelf. The modern submarine cryolithozone 450-0 m thick is wide-spread in the studied region from the coast to the shelf boundary (isobaths of 130–140 m), where it pinches out at a distance of ～380 km from the coast at a depth of ～250 m above the sea level. 相似文献
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Values of root mean square slope 0 and its variations -0 are estimated using the brightness field of an image of the surface of the sea near a speck of light. When 0 and -0 are defined it is highly important to take into account direct as well as dissipated solar radiation.The space-time analysis of the structure of the image brightness field is performed. This gives an opportunity to estimate dispersion relationship and the running effect of a brightness contrast packet. Comparison of the parameters obtained with the theoretical dispersion ratio of internal waves (IW) allows one to make a conclusion that IW surface manifestations are recorded in a frame.UDK 551.463.5 相似文献