{"id":1817,"date":"2008-10-10T23:54:56","date_gmt":"2008-10-11T03:54:56","guid":{"rendered":"http:\/\/mseas.mit.edu\/?p=1817"},"modified":"2021-08-16T20:47:00","modified_gmt":"2021-08-17T00:47:00","slug":"a-multigrid-methodology-for-assimilation-of-measurements-into-regional-tidal-models","status":"publish","type":"post","link":"https:\/\/mseas.mit.edu\/?p=1817","title":{"rendered":"A multigrid methodology for assimilation of measurements into regional tidal models"},"content":{"rendered":"This paper presents a rigorous, yet practical,\r\nmethod of multigrid data assimilation into regional\r\nstructured-grid tidal models. The new inverse tidal\r\nnesting scheme, with nesting across multiple grids, is\r\ndesigned to provide a fit of the tidal dynamics to data\r\nin areas with highly complex bathymetry and coastline\r\ngeometry. In these areas, computational constraints\r\nmake it impractical to fully resolve local topographic\r\nand coastal features around all of the observation sites\r\nin a stand-alone computation. The proposed strategy\r\nconsists of increasing the model resolution in multiple\r\nlimited area domains around the observation locations\r\nwhere a representativeness error is detected in order\r\nto improve the representation of the measurements\r\nwith respect to the dynamics. Multiple high-resolution\r\nnested domains are set up and data assimilation is\r\ncarried out using these embedded nested computations.\r\nEvery nested domain is coupled to the outer\r\ndomain through the open boundary conditions (OBCs).\r\nData inversion is carried out in a control space of the\r\nouter domain model. A level of generality is retained\r\nthroughout the presentation with respect to the choice\r\nof the control space; however, a specific example of\r\nusing the outer domain OBCs as the control space is\r\nprovided, with other sensible choices discussed. In the\r\nforward scheme, the computations in the nested domains\r\ndo not affect the solution in the outer domain.\r\nThe subsequent inverse computations utilize the\r\nobservation-minus-model residuals of the forward computations\r\nacross these multiple nested domains in order\r\nto obtain the optimal values of parameters in the\r\ncontrol space of the outer domain model. The inversion\r\nis carried out by propagating the uncertainty from\r\nthe control space to model tidal fields at observation\r\nlocations in the outer and in the nested domains using\r\nefficient low-rank error covariance representations.\r\nSubsequently, an analysis increment in the control\r\nspace of the outer domain model is computed and the\r\nmultigrid system is steered optimally towards observations\r\nwhile preserving a perfect dynamical balance.\r\nThe method is illustrated using a real-world application\r\nin the context of the Philippines Strait Dynamics\r\nexperiment.","protected":false},"excerpt":{"rendered":"<p>This paper presents a rigorous, yet practical, method of multigrid data assimilation into regional structured-grid tidal models. The new inverse tidal nesting scheme, with nesting across multiple grids, is designed to provide a fit of the tidal dynamics to data in areas with highly complex bathymetry and coastline geometry. In these areas, computational constraints make [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32,182,37,34,28,38,5,54,59,62],"tags":[],"class_list":["post-1817","post","type-post","status-publish","format-standard","hentry","category-numerical-ocean-modeling","category-learning-and-data-assimilation","category-applications-to-ocean-dynamics","category-data-assimilation","category-multiscale-ocean-modeling","category-physical-oceanography","category-publications","category-papers-in-refereed-journals-multiscale-ocean-modeling","category-papers-in-refereed-journals-physical-oceanography","category-papers-in-refereed-journals-data-assimilation"],"_links":{"self":[{"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/posts\/1817","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=1817"}],"version-history":[{"count":4,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/posts\/1817\/revisions"}],"predecessor-version":[{"id":2520,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=\/wp\/v2\/posts\/1817\/revisions\/2520"}],"wp:attachment":[{"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1817"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1817"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mseas.mit.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1817"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}