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This icon generates the gridded input data and the AVAILABLE file needed to run the FLEXTRA trajectory model. The input forecast or analysis fields are automatically retrieved from ECMWF's MARS archive.

The macro language equivalent is flextra_prepare().

About FLEXTRA input  data

FLEXTRA requires input fields on a regular latitude-longitude grid in GRIB format. The input data must contain four three-dimensional fields: the two horizontal wind components, vertical velocity and temperature. Two additional two-dimensional fields are needed as well: topography and surface pressure. The three-dimensional input data has to be available on ECMWF model (i.e. η) levels defined by a hybrid vertical coordinate system. An important restriction is that all the data fields used within a FLEXTRA run must have the same domain size, resolution, number of levels, etc.

All the required fields, with one exception, can be retrieved from ECMWF's MARS archive. The only exception is vertical velocity because FLEXTRA needs the following field for its computations:

 

Mathinline
\dot \eta \frac{\partial \eta}{\partial p}
 

Since only

 

Mathinline
\dot \eta
 

is archived in MARS the full product needs to be computed during the data preparation process (FLEXTRA Prepare does it for you).

FLEXTRA requires all the input GRIB files to be in the same folder using the following file naming convention: ENyymmddhh. In addition to the GRIBs FLEXTRA needs several parameter files as well. Most of these files are automatically generated by Metview in the background, so users do not need to create them. The only exception is the file called AVAILABLE because it can be optionally provided by the user.

 

Info
All the date parameters used for FLEXTRA Prepare has yyyymmdd format. Relative dates are allowed to use: e.g. -1 means yesterday, 0 means today etc.                   

The VAPOR Prepare Editor

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Vapor Input Mode

Specifies the data preparation input mode. The possible values are: Icon and Path.

In Forecast mode the selected steps of a given forecast can be used for data generation Icon mode a set of GRIB icons has to be specified in Vapor Input Data. If the mode is set to Period Path a period with a start and end date and constant time-step can be defined. In this case FLEXTRA Prepare tries to retrieve analysis fields from MARS whenever it is possible (for dates in the past) and uses forecast fields otherwise (for dates in the future).

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Vapor Input Data

Specifies the data preparation mode. The possible values are: Forecast and Period.

In Forecast mode the selected steps of a given forecast can be used for data generation. If the mode is set to Period a period with a start and end date and constant time-step can be defined. In this case FLEXTRA Prepare tries to retrieve analysis fields from MARS whenever it is possible (for dates in the past) and uses forecast fields otherwise (for dates in the future).

VAPOR Surface Params

input data as a set of GRIB icons. It is available when Vapor Input Mode is Icon.

Vapor Surface Params

Specifies the list of The list of the surface parameters from the input GRIB data to be converted into VAPOR format.  . The parameters are identified by their short names. The default value is an empty string. 

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Vapor Upper Params

The Specifies the list of the upper level parameters from the input GRIB data to be converted into VAPOR format. The parameters are identified by their short names. The default value is an empty string.

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Vapor Vertical Grid Type

The Specifies the type of the vertical grid upper level data to be used in VAPOR. The possible values are: Layered and Regular.

If the type is set to Layered VAPOR expects an upper level parameter specifying the elevation of each atmospheric. Internally in VAPOR this parameter is called ELEVATION.  The default value is Layered.

Vapor Elevation Param

The Specifies the name of the upper level GRIB parameter interpreted as the elevation of the upper levels. Available when Vapor Vertical Grid Type is Layered.

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