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11.
The method proposed by Stammer (1998) is modified using eddy statistics from altimeter observation to obtain more realistic eddy diffusivity (K) for the North Pacific. Compared with original estimates, the modified K has remarkably reduced values in the Kuroshio Extension (KE) and North Equatorial Counter Current (NECC) regions, but slightly enhanced values in the Subtropical Counter Current (STCC) region. In strong eastward flow areas like the KE and NECC, owing to a large difference between mean flow velocity and propagation velocity of mesoscale eddies, tracers inside the mesoscale eddies are transported outside rapidly by advection, and mixing length L is hence strongly suppressed. The low eddy probability (P) is also responsible for the reduced K in the NECC area. In the STCC region, however, L is mildly suppressed and P is very high, so K there is enhanced. The zonally-averaged K has two peaks with comparable magnitudes, in the latitude bands of the STCC and KE. In the core of KE, because of the reduced values of P and L, the zonally-averaged K is a minimum. Zonally-integrated eddy heat transport in the KE band, calculated based on the modified K, is much closer to the results of previous independent research, indicating the robustness of our modified K. The map of modified K provides useful informationfor modeling studies in the North Pacific. 相似文献
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The propagation of long-waves, such as tidal waves from the coastal oceam into shallow estuarine waters,often produces asymmetries of veolcity and water level in time series resulting in long-wave breaking.Tian (1994) studied the mechanism of long-wave breaking in an infinite channel with constant depth,considering nth power bottom friction. This study is for the case of a half infinite channel with bottomslope, taking linear bottom friction into account. The wave breaking time and wave breaking location areestimated and the criteria for long-wave breaking in this particular case are obtained. The results obtainedcan also be e asily applied to the case considering wind stress. 相似文献
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渤、黄、东海潮汐开边界的1种反演方法 总被引：7，自引：0，他引：7
潮汐潮流数值模拟中的 1个主要难点在于开边界条件的确定。本文采用伴随方法 ,利用渤、黄、东海的 64个验潮站资料 (潮汐调和常数 ) ,通过反演渤、黄、东海的开边界条件 ,来实现渤、黄、东海 M2 潮波的数值模拟。为了取得较好的数值模拟结果 ,同时对给定的底摩擦系数进行校正 ,计算出调和常数的模拟值与实测值之差的绝对平均值 :振幅差为 4 .0 cm,迟角差为 2 .5°。实验结果较好地体现了渤、黄、东海 M2 潮波的特征。 相似文献
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本文在讨论破碎波判据研究的基础上(文献[1]),根据前人的破碎波研究结果,以及海浪的随机性,建立了一个包含摩擦风速和波浪要素的破碎波判据计算模式,报告了在海上和实验室进行验证的实测结果.其特点是利用良好的现场观测条件和先进的实验设备,对破碎波进行了测量,首次通过划分破碎波的状态,合理地给出了破碎波判据的实测结果,并比较分析了其他几种波浪破碎判据的实测结果及使用范围.本文的计算风浪破碎判据的模式与外海实测结果比较接近,但与实验室测量结果相差较大. 相似文献
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ImODUcrIONBreakingwavesaretheagentSformanyimPohantupperoceanproassesinvolvingtransferofhobontalmornentumfromwindwivestosurfaceimtS.AfaIniliarandspancularpropertyoflongwivespropagatinginaninfiniteorhaif4nfinitechannelwithbottomsl0peisthemeCanismofwavebrmking.Alltheusualtheories(srnallamPlitudeapproxthetionsofAiryandStokes,noTilinearshallowwitertheory,K0rteweg-DeVireSequattonsforsolitaryandcnoidalWhves)areessentiallyapproxirnations,validonlyWhenthefluidadetionissuffidenhysmallcomPatalto… 相似文献
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热带西太平洋暖池次表层暖水的起源--对1997/1998年ENSO事件的分析 总被引：21，自引：1，他引：20
分析了从1955～1999年45年热带、副热带太平洋地区次表层温度距平资料,在分析沿赤道距平极值曲面的深度分布后,认为它基本接近气候温跃层的深度分布.由此分析了1994～1999年该曲面上温度距平的演变发现:1997/1998年El Nino产生时,在热带西太平洋暖池次表层(160 m附近)的温度正距平,是从1994/1995年El Nino在Nino 3区的最大正距平信号传播或演变过来的,整个最大正距平信号的传播轨迹形成一似"8"字的形状.与此同时,当正的温度距平开始从暖池向东传播时,一最大温度负距平信号在Nino 3区出现,并伴随赤道最大正距平信号的东传,在其北部(5～10°N)向西传,然后又向东传最后到达Nino 3区,其传播轨迹形成一扁"0"字形状.分析表明,1997/1998年这次完整的El Nino/La Nina事件主要是在热带流系的温跃层附近形成并传播的. 相似文献
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NLS EQUATION OF INTERNAL WAVES IN WEAKLY STRATIFIED OCEAN 总被引：1，自引：0，他引：1
The NLS (Non-Linear Schr(?)dinger) equation of internal waves in a wekly stratified ocean is der-ived in phase coordnates in terms of the RPM (Reductive Perturbation Method). It was shown thatwhen AB>0 there exist modulation forms of envelope soliton and dn, and tha when AB<0 there arethree modulation forms dark soliton, sn and cn. Only if K~2>B/A(?) . the side-band perturbation is stable,otherwise unstable. For the stable side-band perturbation there ekisis a modulation form of MdV soliton. 相似文献
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渤海、黄海、东海冬季海流场温度场数值模拟和同化技术 总被引：6，自引：0，他引：6
利用NASA高分辨率的卫星遥感资料SST,采用Nudging同化来模拟渤海、黄海、东海的三维温度场,减小用热通量作上边界条件所带来的误差.结果表明,模拟的海流场能较好地反映渤海、黄海、东海的环流特征.数据同化后的温度场优于未经同化的温度场.3个选择站点的同化值与实测值的均方根误差分别为1.307,0.526,0.744,用热通量资料模拟的水温与实测值的均方根误差分别为2.160,0.979,1.330.尽管只同化了海表温度,但数据同化对三维温度场结构都有影响. 相似文献
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斜压海洋水平大尺度波动各模态能量分布对风的响应 总被引：1，自引：0，他引：1
将在南海持续观测近3个月、共28层的潜标海流资料与已有的6 h分辨率的NCEP/NCAR风场资料结合起来进行了分析, 结果表明风场在一个连续的宽频带范围内向海洋上混合层输送能量; 而风的低频异常变化对流场的低频异常变化的作用则是输送能量的“最有效”途径. 但这些能量只有在近惯性频率向混合层以下传播, 并分别按正态分布率分配到正压流、斜压流以及斜压流的各个模态中去. 其中由风引起的正压流与斜压流的能量变化的比值服从正态分布N(0.0242,0.3947); 而前四个斜压模态能量变化在总的斜压能量变化中占的比值也都服从相应的正态分布: 第一斜压模态服从N(0.2628,0.1872), 第二模态服从N(0.1979,0.1504), 第三模态服从N(0.1331,0.1633), 第四模态服从N(0.0650,0.1540). 相似文献