Plotting together trajectories starting at different days

[gboschat]

I would like to plot on a same graph the backward trajectories from a same location source, but starting at 10 different dates. Is this possible ?

I have been able to run the model and display each of these trajectories but I would like to show them all on the same graph..

Thank you for your help

[ariel.stein]

If you are using the GUI to run hysplit, under the display/trajectory menu just write the name of the trajectory output files separated by a "+" (name1+name2+name3+....).
If you are running the trajplot program you will need to use the following command line:
../exec/trajplot -iname1+name2+name3+.....

For help on the command options for this program just type:
../exec/trajplot from the working directory

[gboschat]

Thank you for your help! It is now working.

However, I wish to plot these different back-trajectories leading to my source location at (i) 1000hPa and (ii) 500hPa separately. I've done this by setting the source location to (i) 10m AMSL, but after running the model at each date, I find a slightly different height at my source location for each trajectory (eg 994hPa for one case, 883hPa for another?). Is this simply linked to model errors?

Also, I have been unable to access the archive reanalysis data by using the GUI interface ( the error message says "FTP failed : ftp.arl.noaa.gov -> /pub/archive/reanalysis/RP194801.gbl" , or through this ftp :

ftp://arlftp.arlhq.noaa.gov/pub/archives/reanalysis

Do you know why this is ?

Thanks again for your help

[ariel.stein]

The differences in pressure at your starting point are simply due to variations in the pressure field (passing weather). When you define your source location height at 10 m AMSL the model will read the pressure from the meteorological data at that height at each different stating time; that is what is producing the variations. Unfortunately, HYSPLIT doesn't allow you to start your trajectories at a fixed pressure value.


The ftp was down, please try again.

[gboschat]

Thanks for your help it is working now. For the moment I am running the model for each trajectory separately (each starting at a different date). Do you know if there is any way to run it once for all trajectories (ie for a set of different dates) ?

Thanks for your help

[ariel.stein]

You could use a script to run different trajectories for different days. See the example below:

#!/bin/ksh

#-------------------------------------------------------------
# set default directory structure if not passed through

MDL="/home/hysplit4"
OUT="."
MET="/work"
cd $OUT

#--------------------------------------------------------------
# set model simulation variables

syr=90
smo=08
shr=12

olat=29.0
olon=48.0
olvl=100.0

run=-48
ztop=10000.0
met1="aug90"
met2="sep90"


#----------------------------------------------------------
# basic simulation loop

for sda in 03 04 05 06 07 08 09 10 11 12 13 14 15 \
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31; do

#----------------------------------------------------------
# set up control file for dispersion/concentration simulation

echo "$syr $smo $sda $shr " >CONTROL
echo "1 ">>CONTROL
echo "$olat $olon $olvl ">>CONTROL
echo "$run ">>CONTROL
echo "0 ">>CONTROL
echo "$ztop ">>CONTROL
echo "2 ">>CONTROL
echo "$MET/ ">>CONTROL
echo "$met1 ">>CONTROL
echo "$MET/ ">>CONTROL
echo "$met2 ">>CONTROL
echo "$OUT/ ">>CONTROL
echo "tdump ">>CONTROL

#----------------------------------------------------------
# run the concentration simulation

if [ -f tdump ];then rm tdump; fi
${MDL}/exec/hyts_std
${MDL}/exec/trajplot tdump
mv trajplot.ps plot${smo}${sda}.ps
# mv tdump tdump_${smo}_${sda}

#----------------------------------------------------------
# simulation loop exit

done