| 1 | em_quarter_ss test case: |
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| 2 | |
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| 3 | This test case produces a simulation of a supercell |
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| 4 | thunderstorm. The environmental wind makes a |
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| 5 | "quarter circle" when plotted on a hodograph, and |
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| 6 | is commonly referred to as "quarter circle shear". |
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| 7 | "ss" refers to "super-cell". |
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| 8 | |
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| 9 | The default version of this test case uses a constant |
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| 10 | eddy viscosity for turbulent mixing -> |
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| 11 | diff_opt=1 and km_opt = 1 in namelist.input. |
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| 12 | The Coriolis terms in the model are off (f = 0) |
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| 13 | |
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| 14 | The prognostic TKE can be activated by setting |
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| 15 | diff_opt=2 and km_opt = 2 (see README.namelist). |
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| 16 | |
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| 17 | In idealized cloud model simulations, it is common practice |
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| 18 | to use Coriolis forcing calculated from wind fields defined |
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| 19 | as perturbations from the initial sounding. This option |
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| 20 | can be activated by setting the "dynamics" namelist option |
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| 21 | "pert_coriolis = .true." (the default is false). |
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| 22 | Additionally, the value of the Coriolis parameter "f" |
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| 23 | will need to be reset (from zero to the desired value) |
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| 24 | in WRFV1/dyn_em/module_initialize_quarter_ss.F, and |
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| 25 | the initial state recomputed. |
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| 26 | |
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| 27 | Also, a constant surface drag and heat flux can be specified |
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| 28 | in the TKE formulation by setting the "dynamics" namelist option |
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| 29 | "tke_drag_coefficient = Cd", |
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| 30 | "tke_heat_flux = S". |
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| 31 | The default values are zero. Please note that these are |
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| 32 | specified constants; the formulations do not make use of |
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| 33 | similarity theory. These momentum and heat fluxes will |
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| 34 | not be active if surface and boundary layer formulations are |
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| 35 | activated in the model physics. |
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| 36 | |
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