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The mixed layer depth (MLD) in the upper ocean is an important physical parameter for describing the upper ocean mixed layer.
We analyzed several major factors influencing the climatological mixed layer depth (CMLD), and established a numerical simulation
in the South China Sea (SCS) using the Regional Ocean Model System (ROMS) with a high-resolution (1/12°×1/12°) grid nesting
method and 50 vertical layers. Several ideal numerical experiments were tested by modifying the existing sea surface boundary
conditions. Especially, we analyzed the sensitivity of the results simulated for the CMLD with factors of sea surface wind
stress (SSWS), sea surface net heat flux (SSNHF), and the difference between evaporation and precipitation (DEP). The result
shows that of the three factors that change the depth of the CMLD, SSWS is in the first place, when ignoring the impact of
SSWS, CMLD will change by 26% on average, and its effect is always to deepen the CMLD; the next comes SSNHF (13%) for deepening
the CMLD in October to January and shallowing the CMLD in February to September; and the DEP comes in the third (only 2%).
Moreover, we analyzed the temporal and spatial characteristics of CMLD and compared the simulation result with the ARGO observational
data. The results indicate that ROMS is applicable for studying CMLD in the SCS area. 相似文献
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Song和Banner(2002,简称SB02)利用二维数值波浪水槽(Drimer和Agnon开发,并被Segre改进,简称DAS)研究了深水及中等水深下波群破碎,并依据波群内部能量调制和演变特性提出一个新的波浪破碎阈值.本文利用两个DAS改进模型对SB02的波浪破碎结果进行检验和比较,并研究底面斜坡坡度对SB02破碎判据的影响,其中第一个改进模型(简称MDAS1)修正了DAS中某些积分的计算错误,第二个改进模型(简称MDAS2)在自由表面上用三阶元取代原来的线性元.研究表明: MDAS1和DAS的结果非常一致;而MDAS2和MDAS1相比,波浪临界破碎时的造波板振幅、破碎时刻和局部能量极大值的最大平均变化率δmax都会发生变化,但MDAS2仍然符合SB02提出的破碎阈值.由MDAS1模拟中等水深下波群在坡度为1∶500、1∶300、1∶150和1∶100斜坡上的破碎结果表明:随着斜坡变陡,波群的局部能量极大值μ增大,δmax在临界非破碎情况下微弱变小,在临界破碎情况下急剧增大,SB02提出的破碎阈值在中等水深下坡度小于1∶100的斜坡上仍然有效. 相似文献
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合理的人工鱼礁组合可以有效改善投放水域的流场效应,提高投放水域底层与上层水体之间的扰动。通过使用并行大涡模拟模式及被动示踪物模块,并通过调整人工鱼礁布设间距,研究了在不同背景流速条件(0.1、0.5、0.6和1.0 m/s)下,在不同的横向间距(1L、2L、3L)(L表示人工鱼礁的边长)或纵向间距(1L、2L、3L、4L、5L)情况下,方型人工鱼礁对上升流体积、营养盐的抬升和垂向涡黏系数的影响。研究结果表明,在同一布置条件下,单排布置下的三块人工鱼礁形成的上升流体积大小与来流速度成正相关,体积随来流流速增加而增大6.4%~80.5%;在同一流速条件下,上升流体积大小与纵向布置的间距成正比,与横向布置的间距成反比;在横向布置条件下,当来流速度为1.0 m/s、布设间距为1L时,上升流体积参数最佳。总体来说,上升流体积参数、示踪物浓度差和垂向涡黏性系数均显示横向布置优于纵向布置,相较于布设间距,来流速度是影响上升流体积最重要的因素。 相似文献
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一个二维数值波浪水槽的改进 总被引:3,自引:0,他引:3
对Drimer,Agnon及Segre研发的数值波浪水槽(简称DAS),首先通过修正DAS中某些积分计算的错误,建立了第一个修正模型(MDAS1),使得模型更加准确稳定。其次,将DAS模型自由表面线性元近似替换为更为合理准确的三阶元近似,建立了第二个修正模型(MDAS2),使得模型计算的波面更合理可靠。平底水槽中波群的生成及传播算例表明:与DAS结果相比,MDAS1对波面没有显著影响,而采用三阶元的MDAS2对波面有显著影响。与Hansen和Svendsen的实测资料相比较证实了两个修正模型的有效性。 相似文献
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The effects of different wind input and wave dissipation formulations on the steady Ekman current solution are described. Two formulations are considered: one from the wave modeling (WAM) program proposed by Hasselmann and Komen and the other provided by Tsagareli and Babanin. The solution adopted for our study was presented by Song for the wave-modified Ekman current model that included the Stokes drift, wind input, and wave dissipation with eddy viscosity increasing linearly with depth. Using the Combi spectrum with tail effects, the solutions are calculated using two formulations for wind input and wave dissipation, and compared. Differences in the results are not negligible. Furthermore, the solution presented by Song and Xu for the eddy viscosity formulated using the K-Profile Parameterization scheme under wind input and wave dissipation given by Tsagareli and Babanin is compared with that obtained for a depth-dependent eddy viscosity. The solutions are further compared with the available well-known observational data. The result indicates that the Tsagareli and Babanin scheme is more suitable for use in the model when capillary waves are included, and the solution calculated using the K-Profile Parameterization scheme agrees best with observations. 相似文献
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