Advanced Research WRF (ARW) Technical Note - MMM - University ...

List of Figures
1.1 WRF system components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1 ARW η coordinate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1 Time step integration sequence. Here n represents the number of acoustic time
steps for a given substep of the RK3 integration, and ns is the ratio of the RK3
time step to the acoustic time step for the second and third RK3 substeps. . . . 14
3.2 Horizontal and vertical grids of the ARW . . . . . . . . . . . . . . . . . . . . . . 17
5.1 Schematic showing the data flow and program components in the SI, and how
the SI feeds initial data to the ARW. Letters in the rectangular boxes indicate
program names. GRID GEN: defines the model domain and creates static files
of terrestrial data. GRIB PREP: decodes GriB data. HINTERP: interpolates
meteorological data to the model domain. VINTERP: vertically interpolates
data to model coordinate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.1 Specified and relaxation zones for a grid with a single specified row and column,
and four rows and columns for the relaxation zone. These are typical values used
for a specified lateral boundary condition for a real-data case. . . . . . . . . . . 41
7.1 1-way and 2-way nesting options in the ARW. . . . . . . . . . . . . . . . . . . . 44
7.2 Various nest configurations for multiple grids. (a) Telescoping nests. (b) Nests at
the same level with respect to a parent grid. (c) Overlapping grids: not allowed
(d) Inner-most grid has more than one parent grid: not allowed . . . . . . . . . 45
7.3 Arakawa-C grid staggering for a portion of a parent domain and an imbedded
nest domain with a 3:1 grid size ratio. The solid lines denote coarse grid cell
boundaries, and the dashed lines are the boundaries for each fine grid cell. The
horizontal components of velocity (“U” and “V”) are defined along the normal cell
face, and the thermodynamic variables (“θ”) are defined at the center of the grid
cell (each square). The bold typeface variables along the interface between the
coarse and the fine grid define the locations where the specified lateral boundaries
for the nest are in effect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7.4 Similar to Fig. 7.3, but with a 2:1 grid-distance ratio. . . . . . . . . . . . . . . 48
7.5 Nest grid integration sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.1 Sketch showing the relationship between datasets (circles), and algorithms (rectangles)
of the ARW system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
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