Difference between revisions of "Flextract"

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'''NOTE:'''
 
'''NOTE:'''
  
The minimal timestep for the trajectories to be extracted is 3 hours. The timesteps 00 06 12 18 are given by the ERA-interim reanalysis and the 03 09 15 21 timesteps are given by the forecasts of the model used to produce ERA-interim.
+
The minimal timestep for the trajectories to be extracted is 6 hours, for some periods 3 hours may work as well, check files in input path beforehand. The timesteps 00 06 12 18 are given by the ERA-interim reanalysis and the 03 09 15 21 timesteps are given by the forecasts of the model used to produce ERA-interim.
  
 
'''GET STARTED:'''
 
'''GET STARTED:'''
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Note the 'dot' in the end of the command, for the current location. This will  
 
Note the 'dot' in the end of the command, for the current location. This will  
  
2. Create a settings-file with the following structure:
+
2. Create a settings.txt-file with the following structure:
  
 
<pre>
 
<pre>

Latest revision as of 20:23, 23 April 2020

Flextract reference

AUTHORS:

Alexander Läderach, Harald Sodemann

PURPOSE:

Extract trajectories from FLEXPART particle binary format and convert them to text-based LAGRANTO lsl file format.

USAGE:

./flextract <settings-file>

AVAILABLE DATA:

5 mio. global FLEXPART-trajectories covering 1979-01-02 00:00 to 2019-08-30 15:00 UTC. Stored at Data/gfi/met/flexpart/erainterim/global/global_corr/ (input-path).

NOTE:

The minimal timestep for the trajectories to be extracted is 6 hours, for some periods 3 hours may work as well, check files in input path beforehand. The timesteps 00 06 12 18 are given by the ERA-interim reanalysis and the 03 09 15 21 timesteps are given by the forecasts of the model used to produce ERA-interim.

GET STARTED:

1. Create a link to the flextract executable, located on cyclone to your working directory:

ln -s /Data/gfi/projects/isomet/progs/flextract/flextract .

Note the 'dot' in the end of the command, for the current location. This will

2. Create a settings.txt-file with the following structure:

# --------------------------------------------------------- #
# Settings to extract FLEXPART trajectories from database # 
# NOTE: All lines beginning with # and empty ones ignored # 
# --------------------------------------------------------- #
# Path to the FLEXPART trajectory files (Input) 
/Data/gfi/met/flexpart/erainterim/global/global_corr/

# Path to store trajectories in LAGRANTO-format (Output) 
/Data/gfi/work/<USERNAME>/

# Begin time (Year Month Day Hour Min Sec) 
# NOTE First date for which trajectories are calculated
2018 1 1 0 0 0

# End time (Year Month Day Hour Min Sec) 
# NOTE Last date for which trajectories are calculated
2018 1 3 0 0 0

# Timestep (hours) 
# NOTE always positive
6

# Trajectory length (hours) 
# NOTE positive for forward trajectories, negative for backward
72

# Only consider each nth-particle only (1=each of the 5mio. particles) 
# NOTE: could lead to huge output if too small
1

# Target area (minlon maxlon minlat maxlat) 
5.0 17.1 43.4 49.0

3. Run the flextract program, providing the settings file as argument:

./flextract ./settings.txt

While calculating the trajectories, a percent number will indicate progress of the extraction. The lsl trajectory files will be created in the location specified in the settings.txt file.

4. Read/plot trajectories from the files in lsl format using matlab routines located in /Data/gfi/projects/isomet/matlab:

- read_lsl.m
- traj_filter.m
- traj_plot.m
- traj_plot_vert.m