{"id":811,"date":"2010-09-06T02:52:21","date_gmt":"2010-09-06T06:52:21","guid":{"rendered":"http:\/\/mseas.net16.net\/?p=811"},"modified":"2021-07-30T16:44:42","modified_gmt":"2021-07-30T20:44:42","slug":"multi-scale-modelling-of-coastal-shelf-and-global-ocean-dynamics-2","status":"publish","type":"post","link":"https:\/\/mseas.mit.edu\/?p=811","title":{"rendered":"Multi-scale modelling of coastal, shelf and global ocean dynamics"},"content":{"rendered":"Methods for widening the range of resolved scales (i.e.\r\nperforming multi-scale simulations) in ocean sciences and\r\nengineering are developing rapidly, now allowing multiscale\r\nocean dynamics studies. Having recourse to grid\r\nnesting has been and still is a popular method for increasing\r\nmarine models&#8217; resolution when and where needed and for\r\neasily allowing the use of different dynamics at different\r\nresolution. However, this is not the only way to achieve this\r\ngoal. Various techniques for modifying locally the grid\r\nresolution or dealing with complex-geometry domains are\r\navailable. For instance, composite, structured grids and\r\nunstructured meshes offer an almost infinite geometrical\r\nflexibility.\r\nThis special issue focuses on multi-scale modelling\r\nof coastal, shelf and global ocean dynamics, including the\r\ndevelopment of new methodologies and schemes and their\r\napplications to ocean process studies. Several articles focus\r\non numerical aspects of unstructured mesh space discretisation.\r\nDanilov (2010) shows that the noise developing on\r\ntriangular meshes on which the location of the variables is\r\ninspired by Arakawa&#8217;s C-grid is the largest for regimes\r\nclose to geostrophic balance. The noise can be reduced by\r\nspecific operators but cannot be entirely suppressed,\r\n&#8220;making the triangular C-grid a suboptimal choice for\r\nlarge-scale ocean modelling&#8221;. Then, the companion articles\r\nof Blaise et al. (2010) and Comblen et al. (2010) describe\r\nthe space and time discretisation of a three-dimensional,\r\nbaroclinic, finite element model based on the discontinuous\r\nGalerkin (DG) technique. This is a significant step forward\r\nin the field of finite element ocean modelling, though this\r\nmodel cannot yet be regarded as suitable for tackling\r\nrealistic applications. Ueckermann and Lermusiaux (2010)\r\nalso consider DG finite element techniques, focusing on\r\nbiological-physical dynamics in regions with complex\r\nbathymetric features. They compare low- to high-order\r\ndiscretisations, both in time and space, for regimes in which\r\nbiology dominates, advection dominates or terms are\r\nbalanced. They find that higher-order schemes on relatively\r\ncoarse grids generally perform better than low-order\r\nschemes on fine grids. Kleptsova et al. (2010) assess\r\nvarious advection schemes for z-coordinate, threedimensional\r\nmodels in which flooding and drying is taken\r\ninto account. In this study, the ability to conserve\r\nmomentum is regarded as the main criterion for selecting\r\na suitable method. On the other hand, Massmann (2010) assesses automatic differentiation for obtaining the adjoint\r\nof an unstructured mesh, tidal model of the European\r\ncontinental shelf.\r\nTwo articles deal with grid nesting. Nash and Hartnett\r\n(2010) introduce a flooding and drying method that can be\r\nused in structured, nested grid systems. This can be\r\nregarded as an alternative to flooding and drying techniques\r\nthat are being developed for unstructured mesh models (e.g.\r\nKarna et al. 2010). Then, Haley and Lermusiaux (2010)\r\nderive conservative time-dependent structured finite volume\r\ndiscretisations and implicit two-way embedded\r\nschemes for primitive equations with the intent to resolve\r\ntidal-to-mesoscale processes over large multi-resolution\r\ntelescoping domains with complex geometries including\r\nshallow seas with strong tides, steep shelf breaks and deep\r\nocean interactions. The authors present realistic simulations\r\nwith data assimilation in three regions with diverse\r\ndynamics and show that their developments enhance the\r\npredictive capability, leading to better match with ocean\r\ndata.\r\nVarious multi-scale, realistic simulations are presented.\r\nUsing a finite element ice model and a slab ocean as in\r\nLietaer et al. (2008), Terwisscha van Scheltinga et al.\r\n(2010) model the Canadian Arctic Archipelago, focusing on\r\nthe pathways for freshwater and sea-ice transport from the\r\nArctic Ocean to the Labrador Sea and the Atlantic Ocean.\r\nThe unstructured mesh can represent the complex geometry\r\nand narrow straits at high resolution and allows improving\r\ntransports of water masses and sea ice. Walters et al. (2010)\r\nhave recourse to an unstructured mesh model to study tides\r\nand current in Greater Cook Strait (New Zealand). They\r\nidentify the mechanisms causing residual currents. By\r\nmeans of the unstructured mesh Finite Volume Coastal\r\nOcean Model (FVCOM), Wang et al. (2010) study the\r\nhydrodynamics of the Bohai Sea. Xu et al. (2010) simulate\r\ncoastal and urban inundation due to storm surges along US\r\nEast and Gulf Coasts. A sensitivity analysis reveals the\r\nimportance of precise topographic data and the need for a\r\nbottom drag coefficient accounting for the presence of\r\nmangroves. Finally, Yang and Khangaonkar (2010) resort to\r\nFVCOM to simulate the three-dimensional circulation of\r\nPuget Sound, a large complex estuary system in the Pacific\r\nNorthwest coastal ocean, including variable forcing from\r\ntides, the atmosphere and river inflows. Comparisons of\r\nmodel estimates with measurements for tidal elevation,\r\nvelocity, temperature and salinity are deemed to be\r\npromising, from larger-scale circulation features to nearshore\r\ntide flats.\r\nThis special issue suggests that numerical techniques for\r\nmulti-scale space discretisation are progressively becoming\r\nmature. One direction for future progress lies in the\r\nimprovement of time discretisation methods for the new\r\ngeneration models, so that they can successfully compete\r\nwith finite difference, structured mesh models based on\r\n(almost) constant resolution grids that have been developed\r\nand used over the past 40 years (e.g. Griffies et al. 2009).","protected":false},"excerpt":{"rendered":"<p>Methods for widening the range of resolved scales (i.e. performing multi-scale simulations) in ocean sciences and engineering are developing rapidly, now allowing multiscale ocean dynamics studies. Having recourse to grid nesting has been and still is a popular method for increasing marine models&#8217; resolution when and where needed and for easily allowing the use of [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32,28,5,54],"tags":[],"class_list":["post-811","post","type-post","status-publish","format-standard","hentry","category-numerical-ocean-modeling","category-multiscale-ocean-modeling","category-publications","category-papers-in-refereed-journals-multiscale-ocean-modeling"],"_links":{"self":[{"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/posts\/811","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=811"}],"version-history":[{"count":6,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/posts\/811\/revisions"}],"predecessor-version":[{"id":2512,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/posts\/811\/revisions\/2512"}],"wp:attachment":[{"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=811"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=811"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=811"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}