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This icon runs the FLEXTRA trajectory model.

The macro language equivalent is flextra_run(). 

Info

From Macro/Python the icon can be called as flextra_run().


Tip

A tutorial about using FLEXTRA in Metview can be found here.

What is FLEXTRA?

FLEXTRA is an atmospheric trajectory model used by a wide scientific community. It can be driven by meteorological input data from a variety of global and regional models including ECMWF analyses and forecasts.

FLEXTRA can compute both forward and backward trajectories using various trajectory types such as: three-dimensional, model level, mixing layer, isobaric and isentropic trajectories. Trajectory computations can be carried out in the three different modes. These are as follows:

  1. In NORMAL mode, a group of trajectories is specified starting from the same point but at different times. Several starting points (thus several groups of trajectories) can be defined for a single FLEXTRA run.
  2. In CET mode, trajectories are generated starting from the points of a user-defined uniform grid in a three-dimensional domain.
  3. In FLIGHT mode, both the starting location and starting time for each trajectory can be set individually. This mode is useful to calculate e.g. trajectories released along the flight track of an aircraft.



The FLEXTRA Run Editor

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Flextra Exe Path

Specifies

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a user defined FLEXTRA executable. Both

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absolute and relative path can be given here.

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If it is left blank (this is the default) Metview will use the MV_FLEXTRA_EXE environment variable to locate the executable.

Flextra

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Input Mode

Specifies how the input data path is specified. The possible values are path and icon. When it is set to path we will specify the input data files and the AVAILABLE file by their paths. While in icon mode the input data is specified by a FLEXTRA Prepare icon in FLEXTRA Input Data. The default value is path.

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Flextra Input Data

Specifies the location of the input data files using a FLEXTRA Prepare icon.

Flextra Run Label

Specifies the FLEXTRA run label. The default value is: "FLEXTRA RUN".

Flextra Input

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Path

Specifies the location of the input data files. Both an absolute and relative path can be given here. Enabled when FLEXTRA Flextra Input Mode is path.

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Flextra Available File Path

Specifies the location of the AVAILABLE file using. The default is SAME_AS_INPUT_PATH, which mean that the AVAILABLE file is located in the same directory as the input data. Enabled when FLEXTRA Flextra Input Mode is path.

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Flextra Run Mode

Specifies the run mode for the FLEXTRA simulation.  THe possible values are as follows:

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Specifies the FLEXTRA simulation direction in time. The possible values are: Forward forward and Backward backward. The default value is Forward forward.

Flextra Trajectory Length

Specifies the length of the FLEXTRA simulation. The format is HHH[:MM[:SS]. The default value is: 48 (i.e. 48 hours).

Flextra First Starting Date

Specifies the start date of the period whiten within which the trajectories will be released. Enabled when Flextra Run Mode is set to normal or cet. The format is YYYYMMDDRelative dates are allowed: e.g. -1 means yesterday, 0 means today, etc. 

Flextra First Starting Time

Specifies the start time of the period whiten within which the trajectories will be released. Enabled when Flextra Run Mode is set to normal or cet. The format is HH[:MM[:SS].

Flextra Last Starting Date

Specifies the end date of the period whiten within which the trajectories will be released. Enabled when Flextra Run Mode is set to normal or cet. The format is YYYYMMDDRelative dates are allowed: e.g. -1 means yesterday, 0 means today, etc.

Flextra Last Starting Time

Specifies the end time of the period whiten within which the trajectories will be released. Enabled when Flextra Run Mode is set to normal or cet.  The format is HH[:MM[:SS].

Flextra Starting Time Interval

Specifies the starting interval of trajectories within the starting period. Enabled when Flextra Run Mode is set to normal or cet. The format is HHH[:MM[:SS]. The default value is: 6 (i.e. 6 hours).

Flextra Output Interval Mode

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Specifies the output frequency when Flextra Output Interval Mode is set to interval or both. The format is HHH[:MM[:SS]. The default value is 3, which means 3 hourly output.

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Specifies the list of trajectory types by their as numerical IDs when Flextra Run Mode is set to normal. The possible values are as follows:

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Numerical IDDescription
13 dimensional
2

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model level
3

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mixing layer
4

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isobaric
5

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isentropic

The default value is 1 (three-dimensional trajectories).

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Specifies the level types (as numerical IDs) of the trajectory start points when Flextra Run Mode is set to normal. The possible values are as follows:

Numerical IDDescription
1

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Metres above sea level
2

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Metres above ground level
3

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hPa

The default value is 1 (metres above sea level).

Flextra Cet Types

Specifies the list of trajectory type by their as numerical IDs or strings when Flextra Run Mode is set to cet. The possible values are as follows:

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Numerical IDString (case insensitive)
13d
2model level
4isobaric
5isentropic

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The default value is 1 (three-dimensional trajectories).

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Specifies the level types (as numerical IDs or strings) of the start grid when Flextra Run Mode is set to cet. The possible values are as follows:

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Numerical IDString (case insensitive)Description
1metres aslMetres above sea level
2

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metres aglMetres above ground level
3

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User Exe Path

Specifies a user defined FLEXTRA executable. Both absolute and relative path can be given here. If it is left blank (this is the default) Metview will use the MV_FLEXTRA_EXE environment variable to locate the executable.

User Resources Path

Specifies the location of the user defined parameter files (IGBP_int1.dat, OH_7lev_agl.dat, surfdata.t, surfdepo.t ) needed to run FLEXTRA. Both an absolute and relative path can be given here. If it is left blank (this is the default) Metview will use the MV_FLEXTRA_RESOURCES environment variable to locate the resources. For further details about the resources click here.

Simulation Direction

Specifies the FLEXTRA simulation direction in time. The possible values are: Forward and Backward. The default value is Forward.

Starting Date

Specifies the beginning date of the simulation in YYYYMMDD format.  Relative dates are allowed: e.g. -1 means yesterday, 0 means today, etc.   

Starting Time

Specifies the beginning time of the simulation in HH[:MM[:SS]] format. 

Ending Date

Specifies the ending date of the simulation in YYYYMMDD format.   Relative dates are allowed: e.g. -1 means yesterday, 0 means today, etc.   

Ending Time

Specifies the ending time of the simulation in HH[:MM[:SS]] format. 

Output Rate

Specifies the frequency for the output generation. The output is averaged over the period given in Output Averaging Interval. The format is HHHH[:MM[:SS]]. The default value is 3 (hours).

Output Averaging Interval

Specifies the averaging interval for the output generation in HHHH[:MM[:SS]] format.  If 0 is given here instantaneous values are written into the output files. The default value is 3 (hours).

Output Sampling Rate

Specifies the sampling rate used for the averaging of the output. This period must be shorter than the Output Averaging Interval. The format is HHHH[:MM[:SS]]. The default value is 1 (hour).

Output Field Type

Specifies the type of the gridded output fields. The possible values are:

for forward simulations:

  • none (no gridded output)
  • conc (concentration)
  • mixr (mass mixing ratio)
  • both (concentration and mass mixing ratio)

for backward simulations:

  • none (no gridded output)
  • rtime (residence time/response function)

The default value is conc. For more details about gridded output click here.

Output Flux

Specifies if the fluxes should be computed and written out as a gridded output (on or off). Fluxes corresponding to northward, southward, eastward, westward, upward and downward directions are calculated for each grid cell of the output grid.The control surfaces are placed in the middle of each output grid cell. The default value is off. For more details about flux output click here.

Output Trajectory

Specifies if the plume trajectories should be computed (on or off). The default value is off.  For more details about trajectory output click here.

Output Area

Specifies the area for the gridded output in degrees in S/W/N/E format. The default value is  -90/-180/90/180.

Output Grid

Specifies the grid resolution for the gridded output in degrees as east_west_resolution/north_south_resolution. The default value is 1/1

Output Levels

Specifies the list of height levels of the gridded output. The levels are given in metres units. The default value is an empty list.

User Species Path

Specifies the location of the user defined species files. Both an absolute and relative path can be given here. If it is left blank (this is the default value) Metview will use the MV_FLEXTRA_SPECIES environment variable to locate the species. For more details about the species click here.

Release Species

Specifies the list of the species released for the simulation. At all the release locations the same species are emitted. The species are identified by the NNN number (with leading zeros) appearing in the the name of the SPECIES_NNN files. These files contain the physical and chemical properties of species. For more details about the species click here.

Release Units

Specifies the units of the mass of the released species. The possible options are mass and mixr. The default value is mass. See the table below to find out what the actual units mean.

for forward simulations:

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for backward simulations:

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Releases

Specifies the releases as a group of FLEXTRA Release icons. 

Receptor units

Specifies the concentration units at the receptor. The possible options are mass (mass concentrations) and mixr (mass mixing ratio). The default value is mass. See the table above to find out what the actual units mean.

Receptors

Enables the usage of receptor sites (on or off). When it is enabled the list of receptor sites can be defined via Receptor Names, Receptor Latitudes and Receptor Longitude. The default value is off. For more details about receptor output click here.

Receptor Names

Specifies the list of receptor site names.The default value is an empty list.

Receptor Latitudes

Specifies the list of receptor site latitudes. The default value is an empty list.

Receptors Longitudes

Specifies the list of receptor site longitudes. The default value is an empty list.

Age Classes

Specifies the list of times for the age class calculation. If it is left blank (this is the default value) no age class is defined.  

Particle Splitting

Specifies the interval for particle splitting in HHHH[:MM[:SS]] format. Each particle is split into two after travelling the multiple of this interval. If 0 (default value) is given here particle splitting is disabled.

Sync Interval

All processes are synchronized with this time interval, therefore, all other time constants must be multiples of this value. Output interval and Output Averaging Interval must be at least twice of this value. The default value is 900.

Ctl

Specifies the factor by which the time step must be smaller than the Lagrangian time scale (TL). CTL must be >1 for time steps shorter than the Lagrangian time scale. If CTL<0, a purely random walk simulation is done. The default value -4.

Vertical Timestep Reduction

Specifies the reduction factor (as an integer) for the time step used for vertical wind. The default value is 4.

Subgrid Terrain

Enables subgridscale terrain parametrization (increase of mixing heights due to subgridscale orographic variations) (on or off). The default value is off.

Convection

Enables convection parametrization (on or off). The default value is off.

Output For Each Release

Specifies whether a separate output fields should be generated for each release (on or off). When this option is set to off for forward simulations the output fields for a given species contain the sum of all the releases. For backward simulations it must be set to on. The default value is off.

Quasi Lagrangian

Specifies whether particles should be numbered individually (on) or identified by the release location number (off). The default value is off.

Domain Fill

Enables the domain fill mode. The possible values are as follows:

  • none: domain fill is disabled
  • full: in this mode the the particles are not released at specific locations but the 3D-volume of the first release is taken and the particles are uniformly distributed in the volume proportionally to air density. Each particle will receive the same mass, altogether accounting for the total atmospheric mass. Subsequently, particles can move freely in the atmosphere.
  • o3_tracer: in this mode domain-filling is to simulate a stratospheric ozone tracer. This option is similar to fill option, but only particles in the stratosphere (defined by PV < 2 pvu) are released.

The default value is none.

Sensitivity

Enables computing sensitivity to initial conditions in backward simulations. The possible values are none, mass (mass concentration units) or mixr (mass mixing ratio units). The default value is none.

The ODB Filter Editor

ODB Filename

Specifies the path to the input ODB

ODB Data

Specifies the input ODB as an icon. If both an icon (in ODB Data) and a filename (in ODB Filename) are specified the icon takes precedence.

ODB Query

Specifies the ODB/SQL query to run.

ODB NB Rows

Specifies the maximum number of rows in the result. If -1 is given here the number of rows is not limited in the output. The default value is -1.

Fail On Empty Output

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hPa

The default value is 1 (metres above sea level).

Flextra Flight Types

Specifies the list of trajectory types a numerical IDs or a string when Flextra Run Mode is set to flight. The possible values are as follows:

Numerical IDString (case insensitive)
13d
2model level
4isobaric
5isentropic

The default value is 1 (three-dimensional trajectories).

Flextra Flight Names

Specifies the trajectory names when Flextra Run Mode is set to flight.

Flextra Flight Latitudes

Specifies the latitudes of the trajectory start points when Flextra Run Mode is set to flight.

Flextra Flight Longitudes

Specifies the longitudes of the trajectory start points when Flextra Run Mode is set to flight.

Flextra Flight Levels

Specifies the levels of the trajectory start points when Flextra Run Mode is set to flight.

Flextra Flight Level Units

Specifies the level types (as numerical IDs or strings) of the trajectory start points when Flextra Run Mode is set to flight. The possible values are as follows


Numerical IDString (case insensitive)Description
1metres aslMetres above sea level
2metres aglMetres above ground level
3hPa

The default value is 1 (metres above sea level).

Flextra Flight Starting Dates

Specifies the starting dates of the trajectories when Flextra Run Mode is set to flight. The format is HHH[:MM[:SS]. The default value is: 6 (i.e. 6 hours).

Flextra Flight Starting Times

Specifies the starting times of the trajectories when Flextra Run Mode is set to flight. The format is HH[:MM[:SS].

Flextra Interpolation Type

Specifies the interpolation type. The possible values are as follows:

ValueDescription
1
  • horizontal interpolation bicubic
  • vertical interpolation polynomial
  • temporal interpolation linear
>1
  • horizontal interpolation bilinear         
  • vertical interpolation linear
  • temporal interpolation linear

The default value is 1.

Flextra Cfl Spatial

Specifies the factor by which the time step must be smaller than that determined from the CFL criterion.  This factor must be >1! The default value is.  2.0.

Flextra Cfl Temporal

Specifies the factor by which the time step must be smaller than the time interval of the wind fields.This factor must be >1 The default value is 2.0.