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| kb:nesting [2018/07/29 20:47] – enviadmin | kb:nesting [2018/07/29 20:59] (current) – enviadmin | ||
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| The only difference between example A and B is that in (A) we have used only 3 nesting grid cells around the core domain whereas in (B) 5 of them are used. As the grid size of the nesting grids is increasing with each grid, the area is extending very fast with each extra Nesting Grid. The grid points inside the nesting area have an increasing horizontal resolution with | The only difference between example A and B is that in (A) we have used only 3 nesting grid cells around the core domain whereas in (B) 5 of them are used. As the grid size of the nesting grids is increasing with each grid, the area is extending very fast with each extra Nesting Grid. The grid points inside the nesting area have an increasing horizontal resolution with | ||
| - | <fs x-large>'' | + | $$ \Delta xy (n)= \Delta xy(Main) |
| - | where //dxy(Main)// is the resolution of the main model and //n// is the first grid of the nesting | + | where $\Delta xy(Main)$ is the resolution of the main model and $n$ is the index of the nesting |
| - | + | The more Nesting Grids you use, the lower is the chance that you will get numerical problems because one or more of your model boders | |
| - | The more Nesting Grids you use, the lower is the chance that you will get numerical problems because one or more of your model boder are interfering with internal model dynamics. | + | |
| ENVI-met will warn you, if the flow field is not stable after 10 sec of integration time and suggest to increase the number of Nesting Grids. If you are not sure what causes your problems, you should always try to increase the number of Nesting Grids to be sure that this is not the point of trouble. | ENVI-met will warn you, if the flow field is not stable after 10 sec of integration time and suggest to increase the number of Nesting Grids. If you are not sure what causes your problems, you should always try to increase the number of Nesting Grids to be sure that this is not the point of trouble. | ||
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| ===== Handling of Radiation in the Nesting Area ===== | ===== Handling of Radiation in the Nesting Area ===== | ||
| - | As no buildings are present in the nesting area, the sun radiation can reach the surface without reduction. This might result in an unrealistic overestimation of the surface temperature in the nesting area, especially when only sealed surfaces are used as soil profiles. To overcome this problem, ENVI-met can use radiative values averaged over the main model area instead of the normal radiative fluxes in the nesting area. To enable this function, | + | As no buildings are present in the nesting area, the sun radiation can reach the surface without reduction. This might result in an unrealistic overestimation of the surface temperature in the nesting area, especially when only sealed surfaces are used as soil profiles. To overcome this problem, ENVI-met can use radiative values averaged over the main model area instead of the normal radiative fluxes in the nesting area. This function |
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