Nudging同化方案改进及其在西北太平洋海域M_2分潮模拟中的应用  

Improved Nudging Assimilation Schemes and Their Applications in Simulating M_2 Tide in the Northwest Pacific

作　　者：魏泽勋[1,2] 王永刚[1,2] 高秀敏[1,2] 方国洪[1,2] 

机构地区：[1]国家海洋局第一海洋研究所,山东青岛266061 [2]青岛海洋科学与技术国家实验室区域海洋动力学与数值模拟功能实验室,山东青岛266071

出　　处：《海洋科学进展》2015年第4期431-438,共8页Advances in Marine Science

基　　金：国家自然科学基金委员会-山东省人民政府联合资助海洋科学研究中心项目--海洋环境动力学和数值模拟(U1406404);国家高技术研究发展计划项目--南海及周边海域风浪流耦合同化精细化数值预报与信息服务系统(2013AA09A506)

摘　　要：基于POM模式,以西北太平洋海域为试验海区,针对Nudging松弛项的差分方案及Nudging松弛系数进行了数值试验。结果表明,通过引入Nudging松弛项的潮波模拟结果明显优于未加Nudging松弛项的模拟结果;在松弛系数取值相等情况下,Nudging松弛项采用隐式差分方案的结果要优于采用显式差分方案的结果;Nudging松弛项差分方案不论是显式还是隐式,模拟结果的偏差都随着松弛系数的增加而逐渐减小,当松弛系数增加到最优值后,模拟结果的偏差将随着松弛系数的增加而加大;Nudging松弛项差分方案为显式时,松弛系数太大将导致模式溢出;而Nudging松弛项差分方案为隐式时,能够有效增大松弛系数的阈值。文中还给出了最优Nudging同化方案下西北太平洋海域M2分潮的同潮图。Explicit and implicit finite difference schemes are designed for Nudging relaxation term, and different Nudging relaxation coefficients are tested with numerical experiments based on POM in the Northwest Pacific （NWP）. It shows that simulations with Nudging relaxation term added are better than those without the relaxation term; for a same relaxation coefficient, simulation using implicit Nudging scheme is better than that using explicit one; no matter if implicit or explicit scheme is adopted, deviations between the simulated and the observed tidal harmonics decrease as relaxation coefficient increases, while when the coefficient reaches its optimal value, the deviations start to increase; when Nudging scheme is explicit, computation may overflows if the relaxation coefficient is too large;when Nudging scheme is implicit, it can effectively increase the threshold of relaxation coefficient. Cotidal chart of M2 tide in the NWP derived from the simulation using optimal Nudging assimilation scheme is also demonstrated.

关 键 词：Nudging同化 潮波 数值模拟 西北太平洋 

分 类 号：P731.23[天文地球—海洋科学]