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691.
针对海水养殖区具有类型多样(筏式养殖、围海养殖、网箱养殖等)、差异较小和难以实现高精度分类提取的问题,本文将空洞金字塔卷积模块与U-Net神经网络模型融合,提出一种适用于海水养殖区的多分类提取方法。首先,采用变差函数分析方法发现不同类别的海水养殖区的变差函数波形与基台值的差异;其次,定义一种相仿于变差函数搜索域的不同扩张率空洞卷积并联的卷积结构,用其替换U-Net模型中普通卷积结构,构建ASP-U-Net模型;最后,为验证采用ASP-U-Net模型的海水养殖区分类提取能力,选取7景我国高分1/2号卫星影像为数据源,相较于经典FCN、SegNet、PspNet和经典U-Net模型,ASP-U-Net模型对海洋养殖区的分类提取在多种指标下均最优,这说明使用提出的卷积结构能够有效扩大感受野,更适合于多类海水养殖区的特征表达。 相似文献
692.
河北省海域承载力多层次模糊综合评价 总被引:2,自引:0,他引:2
借鉴有关承载力的研究成果,利用多层次模糊综合评判法对河北省海域承载力进行了评价分析。结果表明:1996—2006年间河北省近海海域承载力一直处于超载状态,但承载状况总体趋于好转;人口和环境污染的加剧、环境治理能力和科技发展水平缓慢、资源供给能力不足是导致河北省海域承载力超载的主要因素。基于此提出了改善河北省海域承载状况的对策建议。 相似文献
693.
阐述了广州海洋观测网建设的迫切性和必要性,对海洋观测网建设在海洋防灾减灾、海岸工程建设及海水养殖等方面的重要意义进行了分析说明。总结广州市海洋观测网建设现状和成果,并利用已有观测数据对2017年台风“天鸽”和“帕卡”期间广州海域水文气象特征、2015—2017年枯水期咸潮入侵特征进行了分析。研究表明, 现有观测数据对台风和咸潮活动均具有较明显的反应,且对海洋防灾减灾工作具有重要的意义;为更有效地利用已有观测数据,将观测数据价值最大化,对观测网建设及运行过程中观测工作机制及业务化流程、数据质量控制、观测站布设合理性以及数据应用分析这几个方面存在的问题进行了探讨,提出了广州海洋观测网的优化、改进措施及未来发展方向。 相似文献
694.
分析了当前海洋经济现状,以秦皇岛为例建立了海洋经济预警模型宏观与微观指标体系,利用3S技术(全球定位系统GPS、地理信息系统GIS和遥感RS)在海洋资源调查、海洋经济预警、海洋灾害预测等可持续发展核心问题中的应用,提出海洋经济预警的系统模型及对策,以期为海洋经济的发展提供理论依据。 相似文献
695.
根据近17年的莆田市气候影响评价资料,结合实地调查,对莆田市台风、暴雨、冰雹、干旱、寒潮等主要气象灾害的基本特点进行了分析。研究表明,近17年莆田市危害最大的气象灾害是台风灾害,其次为洪涝灾害,揭示了几种主要气象灾害之间的相互关系,并提出相应的减灾对策。 相似文献
696.
ABSTRACTHigh seas fisheries remain one of the least transparent global production practices. Distance from shore, coupled with the highly mobile nature of fish stocks, has put attention on new monitoring, control and surveillance technologies to collect spatially referenced data on the location of fishing vessels, gears and even fish stocks and eradicate illegal, unreported and unregulated fishing activity. Faced with their nascent implementation, research is yet to address how these technologies are reconfiguring the roles and responsibilities of public and private actors involved in fisheries management, including who collects and controls fisheries related information. In this paper, we compare three monitoring, control and surveillance technologies that are gaining traction in fisheries; the use of private fish attraction devices in oceanic tuna fisheries, unmanned public drones for marine surveillance and global satellite monitoring of fishing vessels. In doing so, we question how different configurations of actors are structuring flows of information and with what effect on sustainability performance of high seas fisheries. We also explore how these technologies configure new (and imagined) geographies of high seas fisheries which challenge existing modes of fisheries management. 相似文献
697.
Kovacs K Václavík T Haight RG Pang A Cunniffe NJ Gilligan CA Meentemeyer RK 《Journal of environmental management》2011,92(4):1292-1302
Phytophthora ramorum, cause of sudden oak death, is a quarantined, non-native, invasive forest pathogen resulting in substantial mortality in coastal live oak (Quercus agrifolia) and several other related tree species on the Pacific Coast of the United States. We estimate the discounted cost of oak treatment, removal, and replacement on developed land in California communities using simulations of P. ramorum spread and infection risk over the next decade (2010-2020). An estimated 734 thousand oak trees occur on developed land in communities in the analysis area. The simulations predict an expanding sudden oak death (SOD) infestation that will likely encompass most of northwestern California and warrant treatment, removal, and replacement of more than 10 thousand oak trees with discounted cost of $7.5 million. In addition, we estimate the discounted property losses to single family homes of $135 million. Expanding the land base to include developed land outside as well as inside communities doubles the estimates of the number of oak trees killed and the associated costs and losses. The predicted costs and property value losses are substantial, but many of the damages in urban areas (e.g. potential losses from increased fire and safety risks of the dead trees and the loss of ecosystem service values) are not included. 相似文献
698.
典型大气环境玻璃钢天线罩聚氨酯涂层工艺老化行为研究 总被引:1,自引:0,他引:1
通过南海海洋大气环境、海南万宁湿热乡村大气环境、西藏拉萨高原大气环境户外大气暴露对玻璃钢基灭线罩聚氨酯涂层工艺进行了老化试验,运用光泽、颜色、粉化率、SEM等手段测试了涂层在户外大气暴露的性能变化和表面形貌,并进行对比分析。结果表明,在相同大气环境中,工艺玻璃钢板/雷达罩底漆/浅灰航天聚氨酯涂层耐候性能优于工艺玻璃钢板/环氧聚酰胺/弹性聚氨酯磁漆涂层的耐侯性能;对于同种工艺,西沙海洋大气环境对其耐侯性的影响最大,其次是万宁湿热乡村环境,拉萨高原环境影响较小;光照、温度、湿度是涂层老化的主要原因。 相似文献
699.
Theresa S. Presser 《Environmental management》1994,18(3):437-454
Hypothesized to be derived from Cretaceous marine sedimentary rocks, selenium contamination of the Kesterson National Wildlife
Refuge is traced through irrigation drainage to the source bedrock of the California Coast Ranges. This biogeochemical pathway
of selenium is defined here as the “Kesterson effect.” At the refuge ponds, this effect culminated in 1983 in a 64% rate of
deformity and death of embryos and hatchlings of wild aquatic birds. From the previous companion paper on irrigation drainage,
the Kesterson effect has been implicated in nine of 11 reconnaissance areas studied in the western United States. Deformities
have resulted in at least five of these sites. Climatic, geologic, hydrologic, and soil conditions in these reconnaissance
areas are similar to those in the area surrounding Kesterson National Wildlife Refuge in the west-central San Joaquin Valley
of California. In California, selenium, as selenate, was ultimately found weathered with sulfur from marine sources in soluble
sodium and magnesium sulfate salts, which are concentrated by evaporation on farmland soils. The Se, mobilized by irrigation
drainage, is bioaccumulated to toxic levels in refuge wetland ponds that are located mainly in hydrologically closed basins
and thus act as concentrating disposal points. The depositional environment of the ponds may be similar to that of the nutrient-rich
continental shelf edge and slope in which Cretaceous, Eocene, and Miocene sediments found to be seleniferous in the California
Coast Ranges were deposited. Bioaccumulation may be therefore a primary mechanism of selenium enrichment in ancient sediments
in addition to that of the formerly suggested Cretaceous volcanic pathway. 相似文献
700.
王彬辉 《中国环境管理干部学院学报》2000,(2)
长期以来,我国对排污或超标排污实行征收排污费制度。九届人大常委会第13次会议修订通过的《海洋环境保护法》对此进行了改革。本文对此进行了深入分析。 相似文献