This tutorial explains how to convert ECMWF GRIB data into VAPOR format and how to visualise the resulting data in VAPOR.
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Modes
cruitial is the vertical coordinate system,.
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| Level type | Elevation present or can be derived (as z or h) | Vertical grid type | Surface data can be used |
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| pressure | yes | layered | yes |
| pressure | no | regular | no |
| model | yes | layered | yes |
| model | no | regular | no |
| height | yes | regular | yes |
Pressure level data with elevation
This exercise demonstrate how to use pressure level ECMWF GRIB data with VAPOR. We will work with fields from yesterday's forecast on a low resolution grid over Europe.
Getting the GRIB data
First, we retrieve our GRIB data from MARS. We will need two MARS retrieval icons: one for the surface and one for pressure levels.
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| Param | z/t/r/u/v |
| Level | pl |
| Levelist | 1000/950/925/900/850/800/700/600/500/400/300/250/200/150/100 |
| Date | -1 |
| Time | 0 |
| Step | 0/12 |
| Area | 35/-10/65/30 |
| Grid | 1/1 |
Running Vapor Prepare
Having set up the retrievals we can focus on the conversion of the data into the VAPOR format.
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Now save your VAPOR Prepare icon then right click Execute to run the conversion. The will first turn orange then green when the conversion finishes.
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Right click Visualise your VAPOR Prepare icon to start up VAPOR. You will see this window popping up:
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Model level data with elevation
This exercise demonstrate how to use model level ECMWF GRIB data with VAPOR. We will work with fields from yesterday's forecast on a low resolution grid over Europe. The steps required are very similar to the previous exercise (with pressure levels) to only exception is the handling of geopotential.
Getting the GRIB data
First, we retrieve our GRIB data from MARS. We will need two MARS Retrieval icons: one for the surface and one for model levels.
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Geopotential on model levels is not archived in MARS. However, VAPOR Prepare can derive it if tempreature (t), specific humidity (q) and logarithm of surface pressure (lnsp) are available. So we need to ensure that these fields are present in the retrieval. |
Running Vapor Prepare
Having set up the retrievals we can focus on converting the data into the VAPOR format.
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