| 词条 | Arakawa grids |
| 释义 |
The Arakawa grid system depicts different ways to represent and compute orthogonal physical quantities (especially velocity- and mass-related quantities) on rectangular grids used for Earth system models for meteorology and oceanography. For example, the Weather Research and Forecasting Model uses the Arakawa Staggered C-Grid in its atmospheric calculations when using the ARW core. The five Arakawa grids (A-E) were first introduced in Arakawa and Lamb 1977.[1] For an image of the five grids, see the following picture, or Fig. 1 in Purser and Leslie 1988.[2] Arakawa A-gridThe "unstaggered" Arakawa A-grid evaluates all quantities at the same point on each grid cell, e.g., at the grid center or at the grid corners. The Arakawa A-grid is the only unstaggered grid type. Arakawa B-gridThe "staggered" Arakawa B-grid separates the evaluation of the two sets of quantities. e.g., one might evaluate velocities at the grid center and masses at grid corners. Arakawa C-gridThe "staggered" Arakawa C-grid further separates evaluation of vector quantities compared to the Arakawa B-grid. e.g., instead of evaluating both east-west (u) and north-south (v) velocity components at the grid center, one might evaluate the u components at the centers of the left and right grid faces, and the v components at the centers of the upper and lower grid faces. Arakawa D-gridAn Arakawa D-grid is a 90° rotation of an Arakawa C-grid. E.g., instead of evaluating the v velocity components at the centers of the upper/lower grid faces and the u velocity components at the centers of the right/left grid faces, one would evaluate the v velocity components at the centers of the right/left grid faces and the u velocity components at the centers of the upper/lower grid faces. Arakawa E-gridThe Arakawa E-grid is "staggered," but also rotated 45° relative to the other grid orientations. This allows all variables to be defined along a single face of the rectangular domain. References1. ^{{Cite journal | last = Arakawa | first = A. | last2 = Lamb | first2 = V.R. | title = Computational design of the basic dynamical processes of the UCLA general circulation model | journal = Methods in Computational Physics: Advances in Research and Applications | volume = 17 | pages = 173–265 | year = 1977 | doi = 10.1016/B978-0-12-460817-7.50009-4 | url = https://www.sciencedirect.com/science/article/pii/B9780124608177500094| isbn = 9780124608177 }} 2. ^{{Cite journal | last = Purser | first = R. J. | first2 = L. M. | last2 = Leslie | title = A Semi-Implicit, Semi-Lagrangian Finite-Difference Scheme Using Hligh-Order Spatial Differencing on a Nonstaggered Grid | journal = Monthly Weather Review | volume = 116 | issue = 10 | pages = 2069–2080 | date = October 1988 | issn = 0027-0644 | doi = 10.1175/1520-0493(1988)116<2069:ASISLF>2.0.CO;2 }} Further readingHaltiner, G. J., and R. T. Williams, 1980. Numerical Prediction and Dynamic Meteorology. John Wiley and Sons, New York. {{DEFAULTSORT:Arakawa Grids}} 1 : Numerical climate and weather models |
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