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This icon runs the FLEXTRA trajectory model.
From Macro/Python the icon can be called as flextra_run(). |
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: - 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.
- In CET mode, trajectories are generated starting from the points of a user-defined uniform grid in a three-dimensional domain.
- 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.
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The FLEXTRA Run Editor
Flextra 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.
Flextra 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.
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 Path
Specifies the location of the input data files. Both an absolute and relative path can be given here. Enabled when Flextra Input Mode is path.
Flextra Available File Path
Specifies the location of the AVAILABLE file. The default is SAME_AS_INPUT_PATH, which means that the AVAILABLE file is located in the same directory as the input data. Enabled when Flextra Input Mode is path.
Flextra Run Mode
Specifies the run mode for the FLEXTRA simulation. The possible values are as follows:
- 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.
- In cet mode, trajectories are generated starting from the points of a user-defined uniform grid in a three-dimensional domain.
- In filight 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 default value is normal.
Flextra Trajectory Direction
Specifies the FLEXTRA simulation direction in time. The possible values are: forward and backward. The default value is 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 within which the trajectories will be released. Enabled when Flextra Run Mode is set to normal or cet. The format is YYYYMMDD. Relative dates are allowed: e.g. -1 means yesterday, 0 means today, etc.
Flextra First Starting Time
Specifies the start time of the period 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 within which the trajectories will be released. Enabled when Flextra Run Mode is set to normal or cet. The format is YYYYMMDD. Relative dates are allowed: e.g. -1 means yesterday, 0 means today, etc.
Flextra Last Starting Time
Specifies the end time of the period 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
Specifies how the output data (i.e. trajectory waypoints) will be written out into the output file. It can have three values:
- original: The trajectory points are written out into the output file exactly at the computational time steps. In the FLEXTRA terminology these are called flexible time steps.
- interval: The trajectory points are written out into the output file at regular intervals specified by parameter Flextra Output Interval Value. In the FLEXTRA terminology these are called constant time steps.
- both: Two output files will be generated: one for the flexible time steps and one for the constant time steps.
The default value is interval.
Flextra Output Interval Value
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.
Flextra Normal Types
Specifies the list of trajectory types as numerical IDs when Flextra Run Mode is set to normal. The possible values are as follows:
| Numerical ID | Description |
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| 1 | 3 dimensional |
| 2 | model level |
| 3 | mixing layer |
| 4 | isobaric |
| 5 | isentropic |
The default value is 1 (three-dimensional trajectories).
Flextra Normal Names
Specifies the trajectory names when Flextra Run Mode is set to normal.
Flextra Normal Latitudes
Specifies the latitudes of the trajectory start points when Flextra Run Mode is set to normal.
Flextra Normal Longitudes
Specifies the longitudes of the trajectory start points when Flextra Run Mode is set to normal.
Flextra Normal Levels
Specifies the levels of the trajectory start points when Flextra Run Mode is set to normal.
Flextra Normal Level Units
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 ID | Description |
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| 1 | Metres above sea level |
| 2 | Metres above ground level |
| 3 | hPa |
The default value is 1 (metres above sea level).
Flextra Cet Types
Specifies the list of trajectory type as numerical IDs or strings when Flextra Run Mode is set to cet. The possible values are as follows:
| Numerical ID | String (case insensitive) |
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| 1 | 3d |
| 2 | model level |
| 4 | isobaric |
| 5 | isentropic |
The default value is 1 (three-dimensional trajectories).
Flextra Cet Name
Specifies the trajectory name when Flextra Run Mode is set to cet.
Flextra Cet Area
Specify the geographical area of the start grid by a S/W/N/E list.
Flextra Cet Dx
Specifies the start grid resolution in West-East direction in degrees when Flextra Run Mode is set to cet. The default values is 1.
Flextra Cet Dy
Specifies the start grid resolution in South-North direction in degrees when Flextra Run Mode is set to cet. The default values is 1.
Flextra Cet Top Level
Specifies the top level of the start grid volume when Flextra Run Mode is set to cet. The default values is 1.
Flextra Cet Bottom Level
Specifies the bottom level of the start grid when Flextra Run Mode is set to cet. The default values is 1.
Flextra Cet Dz
Specifies the start grid vertical resolution when Flextra Run Mode is set to cet. The default values is 1
Flextra Cet Level Units
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:
| Numerical ID | String (case insensitive) | Description |
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| 1 | metres asl | Metres above sea level |
| 2 | metres agl | Metres above ground level |
| 3 | hPa |
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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 ID | String (case insensitive) |
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| 1 | 3d |
| 2 | model level |
| 4 | isobaric |
| 5 | isentropic |
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 ID | String (case insensitive) | Description |
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| 1 | metres asl | Metres above sea level |
| 2 | metres agl | Metres above ground level |
| 3 | hPa |
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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:
| Value | Description |
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| 1 | - horizontal interpolation bicubic
- vertical interpolation polynomial
- temporal interpolation linear
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| >1 | - horizontal interpolation bilinear
- vertical interpolation linear
- temporal interpolation linear
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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.