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Yongkang Xue, Ratko Vasic, Zavisa Janjic, Fedor Mesinger, and Kenneth E. Mitchell

surface boundary conditions from specification or prediction by a coupled ocean and/or land surface model, as well as by lateral boundary conditions (LBCs) from a GCM or reanalysis at regular temporal intervals. In this paper, we will refer to this lateral nesting approach as the dynamic downscaling method (DDM). There are a number of issues concerning the use of the DDM ( Laprise et al. 2000 ; Denis et al. 2002 ). The most important issue is whether, and if so under what conditions, the DDM is

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Xiaoxue Wang, Yuguo Li, Kai Wang, Xinyan Yang, and Pak Wai Chan

mesoscale surface parameterizations ( Krayenhoff and Voogt 2007 ; Yang and Li 2015 ). Although it is necessary to include the variations in daily surface temperature, the existing CFD models or simulations do not consider the diurnal cycle of the atmospheric boundary layer ( Blocken and Gualtieri 2012 ). Coupling the existing surface temperature model with CFD models is challenging. The commonly used thermal boundary conditions include constant temperature (Dirichlet boundary condition), constant heat

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Dale R. Durran, Ming-Jen Yang, Donald N. Slinn, and Randy G. Brown

604 MONTHLY WEATHER REVIEW VOLUME 121Toward More Accurate Wave-Permeable Boundary Conditions DALE R. DURRAN AND MING-JEN YANGDepartment of Atmospheric Sciences, University of Washington, Seattle, Washington DONALD N. SLINNDepartment of Mechanical Engineering, University of Washington, Seattle, Washington RANDY G. BROWNDepartment of Atmospheric Sciences

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W. D. Smyth

frictionless, ∂ u /∂ z = ∂ υ /∂ z = 0. Conditions of constant temperature and salinity, b i = 0, are imposed. It will be seen that the boundaries have little effect on interleaving modes but they destabilize two additional classes of modes that must be carefully distinguished as their oceanic significance is uncertain. b. Flow decomposition Motions are assumed to take place in a frontal zone of scale sufficiently large that it can be represented locally by uniform property gradients. The fields are

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A. F. Bennett and P. E. Kloeden

990JOURNAL OF THE ATMOSPHERIC SCIENCESVOLUME 35Boundary Conditions for Limited-Area ForecastsA. F. BENNETTGeophysical Fluid Dynamics Laboratory, Monash University, Clayton, Vicioria, 3168, AustraliaP. E. KLOEDENSchool of MathemaJical and Physical Sciences, Murdoch University, Murdoch, Western Australia, 6153, Australia(Manuscript received 6 December 1977, in final form 22 February 1978)ABSTRACTThe smo~thness of solutions of the barotropic and barodinic filtered and primitive equations in

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Mark Hedley and M. K. Yau

SEPTEMBER 1988 MARK HEDLEY AND M. K. YAU 1721Radiation Boundary Conditions in Numerical Modeling MARK HEDLEY AND M. K. YAUDepartment of Meteorology, McGill University, Montreal, Canada(Manuscript received 21 October 1987, in final form 5 February 1988)ABSTRACT A two-dimensional anelastic model is used to study the propagation of errors arising from the use of openlateral boundaries. Reference experiments were performed

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Pallav Ray, Chidong Zhang, Jim Dudhia, and Shuyi S. Chen

rest of the globe are controlled through the boundary conditions, which allow their influences on the MJO initiation to be tested. For example, any signal related to prior MJOs can be filtered from the boundary forcing to see how external influences affect the MJO ( Gustafson and Weare 2004a , b ). But the removal of the MJO frequency alone cannot entirely eliminate the influence of the MJO from the boundary conditions, because the MJO may influence smaller-scale features that are coupled to

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Paola Cessi and Christopher L. Wolfe

(and, less importantly, no-slip boundary), and there must be no flux of buoyancy into the wall. In general, these conditions are fulfilled in thin boundary layers where geostrophy is broken. In our numerical simulations we find that in these thin boundary layers, Reynolds stresses become large in the alongshore momentum balance, while the across-shore balance remains geostrophic. In this way, the velocity along the boundary is geostrophic but the component normal to the boundary is not. This is the

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I. Shulman

1. Introduction With the rapidly increasing amount of available observations, results of model simulations, and newly gained knowledge of physical processes, the development of data assimilation methods is in great demand. One of the areas of application of data assimilation methods is the specification of open boundary conditions (OBCs) for limited-area models. The use of data assimilation techniques improves the model predictions and avoids the ill-posed, point-wise treatment of OBCs

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A. McDonald

incorporate the boundary conditions into equations that describe unidirectional waves traveling out of the area (and into the area when nested). In section 2 we will use this idea to arrive at one-way wave equations for the boundaries that are correct to a well-defined level of approximation. Robert and Yakimiw (1986) point out that, since most boundary strategies contain difficulties that cannot be easily identified when they are considered in the framework of realistic models, it is a good idea to

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