An approximated method for the solution of elliptic problems in thin domains: Application to nonlinear internal waves     

A. Scotti  S. Mitran   《Ocean Modelling》2008,25(3-4):144-153

Realistic numerical simulations of nonlinear internal waves (NLIWs) have been hampered by the need to use computationally expensive nonhydrostatic models. In this paper, we show that the solution to the elliptic problem arising from the incompressibility condition can be successfully approximated by a few terms (three at most) of an expansion in powers of the ratio (horizontal grid spacing)/(total depth). For an n dimensional problem, each term in the expansion is the sum of a function that satisfies a one-dimensional second-order ODE in the vertical direction plus, depending on the surface boundary condition, the solution to an n-1 dimension elliptic problem, an evident saving over having to solve the original n-dimensional elliptic problem. This approximation provides the physically correct amount of dispersion necessary to counteract the nonlinear steepening tendency of NLIWs. Experiments with different types of NLIWs validate the approach. Unlike other methods, no ad hoc artificial dispersion needs to be introduced.  相似文献   

海洋主体功能区划与海洋功能区划关系研究     

王倩  郭佩芳 《海洋湖沼通报》2009,(4)

开展海洋主体功能区划与海洋功能区划的关系和衔接研究,是保障两者在我国海洋事业中充分发挥各自作用的基础.本文从编制及实施2个方面理顺海洋主体功能区划与海洋功能区划的关系,促进两者在实际工作中的相互结合.  相似文献   

3S技术支持下的小型遗址提取方法   总被引：1，自引：1，他引：0  

高飞  王心源  吴立  白恩亮  何磊 《地理空间信息》2009,7(4):75-78

针对仅利用地物光谱分析方法不能识别某些小型遗址的现状，提出基于地物空间关系知识，多源信息复合提取遗址的思路获取目标信息。以安徽省巢湖柘皋地区为例，利用SPOT-5卫星影像和地形图数据，综合运用3S技术进行小型遗址信息提取研究。经过和巢湖文管部门普查记录对比，证明了该方法有效性。该方法可缩小遗址探查范围，为考古普查工作节约大量时间、人力和物力。  相似文献   

海洋技术标准涉及知识产权问题浅析   总被引：1，自引：0，他引：1  

汤海荣 《海洋技术学报》2008,27(3)

随着海洋科学技术的不断发展,海洋技术标准中涉及知识产权的问题日益突出.如何确定海洋技术标准与知识产权之间的关系,成为亟待研究解决的问题.文中阐述了标准与知识产权的特性,指出二者之间的冲突体现.并对国内外现状进行了研究与分析,在此基础上提出了确定海洋技术标准与知识产权关系的几点具体思考与建议,寻找海洋技术标准中涉及知识产权问题的解决途径,探索涉及知识产权的海洋技术标准管理模式.  相似文献   

Specific Relationship between the Surface Air Temperature and the Area of the Terra Nova Bay Polynya,Antarctica   总被引：1，自引：0，他引：1  

Yifan DING  Xiao CHENG  Xichen LI  Mohammed SHOKR  Jiawei YUAN  Qinghua YANG  Fengming HUI 《大气科学进展》2020,37(5):532-544

Antarctic polynyas play an important role in regional atmosphere?ice?ocean interactions and are considered to help generate the global deep ocean conveyer belt.Polynyas therefore have a potential impact on the Earth’s climate in terms of the production of sea ice and high-salinity shelf water.In this study,we investigated the relationship between the area of the Terra Nova Bay polynya and the air temperature as well as the eastward and northward wind based on the ERA5 and ERAInterim reanalysis datasets and observations from automatic weather stations during the polar night.We examined the correlation between each factor and the polynya area under different temperature conditions.Previous studies have focused more on the effect of winds on the polynya,but the relationship between air temperature and the polynya area has not been fully investigated.Our study shows,eliminating the influence of winds,lower air temperature has a stronger positive correlation with the polynya area.The results show that the relationship between the polynya area and air temperature is more likely to be interactively influenced.As temperature drops,the relationship of the polynya area with air temperature becomes closer with increasing correlation coefficients.In the low temperature conditions,the correlation coefficients of the polynya area with air temperature are above 0.5,larger than that with the wind speed.  相似文献   

基岩水与平原水转换关系的地球物理勘查技术探讨   总被引：3，自引：0，他引：3  

武毅  郭建强  朱庆俊  程旭学  孙振洪 《地球学报》2004,25(3):369-372

基岩水与平原水转化关系的研究是搞清地表水与地下水转化途径、方式及流量进而进行水资源评价的一个重要内容。本文以河西走廊地区为例,分析了地球物理勘查技术对解决上述问题的可能性,同时结合该地区地质地貌特点,选用了EH-4电导率成像系统、自然电位法技术组合进行了实例勘查,取得了较好的效果,为前人的假说提供了科学依据,也为该内容的研究提供有效的手段。  相似文献   

地窝堡机场东南大风特征及其大气结构     

杨洪儒  王楠 《干旱气象》2014,(3):393-398

按照民航系统气象行业标准要求,结合乌鲁木齐国际机场的具体情况,给出乌鲁木齐机场东南大风的定义,并应用乌鲁木齐机场1978~2012年间逐时观测的风速风向对机场东南大风的特征进行分析,然后再引入水跃理论和Froude数,对机场东南大风发生时的大气结构做解析。结果表明:(1)1980年代与2000年代至今,为东南大风的兴盛期,1990年代为东南大风的低值期;(2)东南大风主要集中出现在春秋季,其中尤以4月出现次数最多,占总出现次数的36.4%;(3)早晨至中午期间,东南大风多发且风速较大;午后至夜间,东南大风发生次数少,且风速也相对较小;(4)东南大风的持续时间以低于5 h为主,其次为持续11 h以上的大风,而持续时间在5~11 h之间的大风出现最少;(5)对于4月和11月而言,大风发生时达坂城与本场的气压差与同时次本场的温度垂直递减率存在显著的线性关系。  相似文献   

基于不同海拔高度的雷达降水估测试验   总被引：3，自引：2，他引：1       下载免费PDF全文

范江琳  青泉  马力 《气象科学》2014,34(1):66-71

在国内外雷达定量估测区域降水量一些方法基础上,将降水类型、地理位置和海拔高度同时纳入考虑范畴,在成都CINRAD/SC雷达站(海拔高度596.5 m)200 km范围内选择实验区,并按海拔高度将所选区域分为3区。然后利用2010年7—8月的雷达体扫资料以及同时段、同时次的雨量计数据,采用最优化算法分别在每个区域内修订传统Z-I关系中的"A,b"系数,以得到不同海拔地区的Z-I关系和每小时雨量估测值。研究表明,与直接采用传统的Z-I关系定量测量降水相比,各个区域内,经改善后的Z-I关系准确率提高了20%左右,算法相对简单,适合业务使用。  相似文献   

鳗鲡目鱼类线粒体蛋白质编码基因易位及系统演化关系分析     

申欣  田美  孟学平  程汉良  阎斌伦 《海洋学报》2014,36(4):73-81

鳗鲡目鱼类线粒体基因组的基因组成较为保守,在58个线粒体基因组中,仅有3个物种存在基因数量的差异。在19个鳗鲡目鱼类线粒体基因组中存在主编码基因的重排。主编码基因的变异位点分析结果支持nad5、nad4和nad2基因作为cox1和lrRNA基因辅助的分子标记。鳗鲡科Anguillidae的20个种(亚种)聚在一起,强烈支持鳗鲡科为单系群(BPP=100)。鳗鲡科下属的3个类群(大洋洲类群、大西洋类群和印度洋-太平洋类群)也同时得到有力的验证(BPP均为100)。线鳗科Nemichthyidae和锯齿鳗科Serrivomeridae亲缘关系最近,二者聚类后,与鳗鲡科Anguillidae构成姊妹群(BPP=100)。在囊喉鱼亚目Saccopharyngoidei中,宽咽鱼科Eurypharyngidae与囊鳃鳗科Saccopharyngidae聚类(BPP=100),同时,单颌鳗科Monognathidae与月尾鳗科Cyematidae聚类(BPP=100),4个科聚在一支,支持囊喉鱼亚目为单系群(BPP=100)。在囊喉鱼亚目线粒体基因组中,3个物种(吞鳗Eurypharynx pelecanoides、拉文囊鳃鳗Saccopharynx lavenbergi和杰氏单颌鳗Monognathus jesperseni)存在主编码基因的重排。16种鳗鲡(细美体鳗Ariosoma shiroanago、短吻颈鳗Derichthys serpentinus、凯氏短尾康吉鳗Coloconger cadenati、鸭颈鳗Nessorhamphus ingolfianus、龟草鳗Thalassenchelys sp.、粗犁齿海鳗Cynoponticus ferox、百吉海鳗Muraenesox bagio、巨斑花蛇鳗Myrichthys maculosus、大吻沙蛇鳗Ophisurus macrorhynchos、几内亚副康吉鳗Paraconger notialis、哈氏异康吉鳗Heteroconger hassi、小头鸭嘴鳗Nettastoma parviceps、弱头鳗Leptocephalus sp.、斑点长犁齿鳗Hoplunnis punctata、尖吻小鸭嘴鳗Facciolella oxyrhyncha和星康吉鳗Conger myriaster),与鳗鲡目线粒体主编码基因的原始排列相比,共享nad6基因的易位。同时,基于线粒体基因组13个蛋白质编码基因构建的系统演化树,强烈支持这16个物种聚为一支(BPP=100)。然而,由此而带来的海鳗科Muraenesocidae、拟鯙科Chlopsidae和糯鳗科Congridae是否为单系群的问题,值得今后深入探究。  相似文献   

Optical closure of parameterized bio-optical relationships     

贺双颜  贺明霞 《中国海洋湖沼学报》2014,32(2):480-489

An optical closure study on bio-optical relationships was carried out using radiative transfer model matrix operator method developed by Freie Universitt Berlin.As a case study,the optical closure of bio-optical relationships empirically parameterized with in situ data for the East China Sea was examined.Remote-sensing refl ectance(R rs)was computed from the inherent optical properties predicted by these biooptical relationships and compared with published in situ data.It was found that the simulated R rs was overestimated for turbid water.To achieve optical closure,bio-optical relationships for absorption and scattering coeffi cients for suspended particulate matter were adjusted.Furthermore,the results show that the Fournier and Forand phase functions obtained from the adjusted relationships perform better than the Petzold phase function.Therefore,before bio-optical relationships are used for a local sea area,the optical closure should be examined.  相似文献