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Preparations

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First, set the input data parameters:

The selected option ('Path') for parameter Flextra Input Mode indicates that we want to specify the input data and the AVAILABLE file by their paths. Because the AVAILABLE file is also located in the same directory as the input data we simply set parameter Flextra Available File Path to SAME_AS_INPUT_PATH (it is the default value). Otherwise the full path to the AVAILABLE file should have been typed in.

In the next step we will specify the starting dates of the group of trajectories we want to generate:

Here we set the run mode to 'NORMAL' and defined a set of forward trajectories starting on 11 January 2012 at 3, 9,12 and 15 UTC. We set the length of the trajectories to 72 h and specified that the output data (i.e. trajectory waypoints) will be written out every three hours.

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The last step is to define the starting point parameters:

With these settings we specified the trajectory type to be three-dimensional (see below for the list of IDs for trajectory types) and set the starting point to volcano Katla (on Iceland) with the height of 1512m.

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First, we need to set the symbol plotting type:

With these settings we will plot markers (symbols) in the plot. We also set Symbol Table Mode to 'Advanced' so that we can define value intervals to which a separate maker type, colour and size can be assigned. We will construct these intervals by using the trajectory IDs. In this way the points of a given trajectory will all belong to the same interval.

The next step is to set the line properties:

This means that we will connect the points of a given trajectory and use the same colour for the lines as for the symbols they connect.

The intervals should be set carefully so that each trajectory ID (we have five trajectories with IDs ranging from one to five) should have a separate interval:

The settings above define the following intervals: 

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The last step is to specify the graphical properties we want to assign to the intervals:

With these settings we will automatically generate our colour palette from a colour wheel by interpolating in clockwise direction between Symbol Advanced Table Min Level Colour and Symbol Advanced Table Max Level Colour.

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Copy your 'run_normal' FLEXTRA Run icon (either right-click + duplicate, or drag with the middle mouse button), and rename the duplicate 'run_normal_back' by clicking on its title. Open its editor and start editing the date and time related parameters (the input data parameters are already set correctly for us so we do not need to change them):

Here we set the run mode to 'NORMAL' and defined a set of backward trajectories ending on 14 January 2012 at 3, 9,12 and 15 UTC. The trajectory length will be 72 h and the output data (i.e. trajectory waypoints) will be written out every three hours.

We finish the editing by setting the end point parameters:

We selected Reading as the end point and set the height to 1500 metres. We defined the trajectory type to be three-dimensional.

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First, we need to set the input data parameters (in the same way as we did it in Part 3 ):

In the next step we will specify the run mode and some global parameters valid for all the trajectories:

Here we set the run mode to 'CET' and defined a set of forward trajectories starting on 11 January 2012 at 3 UTC. The trajectory length will be 72 h and the output data (i.e. trajectory waypoints) will be written out every three hours. Please note that for simplicity we defined only one starting time (of course we could have defined multiple ones just like in the previous chapters).

We finish the editing by setting the starting point grid:

With these settings we defined a horizontal grid with only one point (exactly at the position of volcano Katla) and specified four vertical layers from 1500 to 3000 m above seal level.

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Create a new FLEXTRA Run icon and rename it 'run_flight' then open its editor.
First, we need to set the input data parameters (in the same way as we did it in Part 3 ):

In the next step we will specify the run mode and some global parameters valid for all the trajectories:

Here we set the run mode to 'FLIGHT' and defined a set of forward trajectories with the length of 72 h. The output data (i.e. trajectory waypoints) will be written out every three hours. Please note that this time we did not define any starting dates because in FLIGHT mode each starting point has its own starting date (see below). So parameters like Flextra First Starting Date etc. are disabled.

We finish the editing by setting the starting points, dates and times:

Here we set the trajectory mode to 'FLIGHT' and defined an imaginary flight track called 'track' with 3 points each being valid at a different time.

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Please find below the list of the metadata keys used by flextra_group_get():

Step 2 - Accessing Individual Trajectory Data

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Please find below the list of the metadata keys used by flextra_tr_get():

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multiple_output multiple_output

Multiple Outputs

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Open the editor of 'run_multi' and start editing the starting point parameters (now we will use the same input data and starting date settings as in the original icon so we do not need to change these settings):

Here we defined two starting points: volcano Katla (as in Part 3 ) and volcano Stromboli. We set the starting heights to the real heights of these volcanoes and again we defined the trajectory types to be three-dimensional.

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First, open its editor and set the following parameters:

The selected option ('Forecast') for parameter Flextra Prepare Mode indicates that we want to generate the input data from a given forecast. We specified the run date (-1 means yesterday) and run time of the forecast and defined the forecast steps as well. We used a relative date here because MARS retrievals are much faster for current dates.

In the next step we define the area and grid:

We also indicate that we want to reuse the already existing input data (the meaning of this parameter will be explained later in detail):

Last, we need to define the output directory:

Here you need to define the output directory where the GRIB files and the AVAILABLE file will be generated. Please note that the resulting files are rather small (around 1.5 Mb in total) so probably you do not need to worry about your quota.

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