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First start Metview; at ECMWF, the command to use is metview4_new metview (see Metview at ECMWF for details of Metview versions). You should see the main Metview desktop popping up.
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- For layered grids VAPOR expects a parameter specifying the elevation of each 3D level in the input data. This is typically the case for pressure or model level (η levels) data with height or geopotential available (or it can be computed).
- For regular grids the 3D levels are supposed to be equidistant (in the user coordinate space). This type can be used when the data is available on equidistant hight height levels.
When pressure or model level data is present without height information the situation is somewhat special. The grid in this case is not layered but can be regarded as regular in its own coordinate space (pressure or model levels) letting the z axis simply represent pressure or model levels in the 3D scene rendered in VAPOR.
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Then you need to define the list of GRIB parameters you want to see in VAPOR.
| Vapor 2d Params | z/2t/10u/10v |
| Vapor 3d Params | t/u/v/r |
| Info |
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Internally VAPOR Prepare converts surface geopotential to metres and rename it HGT. |
The vertical coordinate system has to be set carefully:
| Vapor Vertical Grid Type | Layered |
| Vapor Elevation Param | z |
| Vapor Bottom Coordinate | 0 |
| Vapor Top Coordinate | 16000 |
Here you set the vertical grid type to 'Layered' and defined geopotential (z) as the parameter holding the elevation of the vertical layers (pressure levels). You also specified the vertical coordinate range (in metres) that VAPOR will display.
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The last step is to specify the name and location of the results of the conversion:
| Vapor Vdf Name | tut_pl |
| Vapor Output Path | your_path_on_the_filesystem |
With these settings a VDF file called 'tut_pl.vdf' will be created in the directory you specified. All the other VAPOR data files will be placed into a subdirectory called 'tut_pl_data'.
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Then you need to define the list of GRIB parameters you want to see in VAPOR.
| Vapor 2d Params | z/2t/10u/10v |
| Vapor 3d Params | t/u/v/q |
The vertical coordinate system has to be set carefully:
| Vapor Vertical Grid Type | Layered |
| Vapor Elevation Param | z |
| Vapor Bottom Coordinate | 0 |
| Vapor Top Coordinate | 16000 |
Here you set the vertical grid type to layered and defined geopotential (z) as the parameter holding the elevation of the vertical layers (model levels). We also specified the vertical coordinate range (in metres) that VAPOR will display for this data.
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Last, we specify the name and location of the results of the conversion:
| Vapor Vdf Name | tut_ml |
| Vapor Output Path | your_path_on_the_filesystem |
Now save your VAPOR Prepare icon then right click Execute to run the conversion. The icon will first turn orange then green when the conversion finishes.
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