CHyM tutorial
Marco Verdecchia – Trieste, September 8/9, 2011
Outline
 Few suggestions (my opinion, not Gospel!)
 Quick description of CHyM user interface
 Homework
Using CHyM to rebuild the basin DN (today)
Modify CHyM to refine parameterization or calibration
What happens if you run a
numerical model?
It does not work
properly
Code problem
It works properly
Parameterization
problem
CHyM is a complex numerical model, few preliminary steps are needed
before to use of modify it.
Understand what happens running it as it is
What happens if you change a single parameter
Modify only one parameter!!
Add a wrong line in the code and see what happens…
Try to apply CHyM to a basin you are familiar with
CHyM: install procedures
tar –xvf /afs/ictp/public/shared/smr2262/chym.tar.gz
Create a chym directory with the chym code
What CHyM directory will contain
chym
script
chymlib.a
museo
-> /home/netapp-clima/scratch/museo
If NCAR Graphic package is available
You may want to use CHyM graphic tools
ncarg -> /home/netapp-clima/scratch/ncarg
bin/
chymlab
What happens if you run CHyM script?
The CHyM fortran code is created using the value of few csh parameters you set
The fortran code is compiled and linked with CHyM libraries to create the executable
Run chym executable that use museo db.
Delete all the unneeded files
chym.f
compilation
chym.exe
run
chymlib.a
ncarglib
museo
files
chym
Output
Run CHyM script and understand what is happening(1)
Run CHyM script and understand what is happening(2)
Run CHyM script and understand what is happening(3)
Run CHyM script and understand what is happening(4)
Run CHyM script and understand what is happening(5)
Run CHyM script and check if it actually happen...
tar –xvf /afs/ictp/public/shared/smr2262/chym.tar.gz
cd chym
./chym
What you need to modify inside CHyM script
CHyM script parameters (1)
CHyM parameters affecting CHyM output file
CHyM script parameters (2)
CHyM parameters affecting CHyM output file
CHyM script parameters (3)
CHyM parameters affecting Prec./Temp input
Temperature field from MM5
Temperature field after CA algorithm
ERA40-ERAInterim
CHyM script parameters (3)
CHyM script parameters (3)
CHyM script parameters (4)
CHyM parameters affecting Graphic output
Using CHyM Model (1)
Add error(s) to CHyM code and check what happen
Set TITLE “CHyM 4.66 – ICTP School”
Set TITLE “CHyM 4.66 – ICTP School
do ih=1,nsli
call groundwater
do ih=1,nsli
hello
call groundwater
What you need to modify inside CHyM script
CHyM: script
set NLON = 300
set NLAT = 175
set SLON = 6.50
set SLAT = 43.80
# number of longitudes set DIJ = 0.020
# number of latitudes
set DEMF = 3
# 1st longitude
# 1st latitude
NLAT
SLON,SLAT
NLON
# lat-lon resolution
# 1 Italy, 2 world, 3 both
Where CHyM script parameters are listed? (0)
http://cetemps.aquila.infn.it/mvlib/11.html
It contains:
A table with the list and the documentation of the utilities included in the chymlib.a
library. You may want to use this tools to develop your application
A table with the information contained in the header of CHyM output files
A table with CHyM script parameters
It will contain (next week):
A link to this presentation
A link to the kit to the updated CHyM model kit (chym.tar.gz)
A link to the reference manual (we are writing it…)
Where CHyM script parameters are listed? (1)
Where CHyM script parameters are listed? (2)
Where CHyM script parameters are listed? (3)
CHyMLab utility (1)
•Requires that NCAR Graphic libraries are installed on your platform and allows to
produce different graphic output
•Allows offline analysis of CHyM output file
•Interactive and bach interface
•Provided but not supported… error may occurr. Bugs will be fixed, check new versions
often
CHyMLab utility (2)
If you have not the “current directory” in the path you have to have to
Invoke the utility specifying the path, namely:
./chymlab tmp/00123100.chym
CHyMLab utility (3)
CHyMLab utility (4)
CHyMLab utility (5)
CHyMLab utility (6)
CHyMLab utility (7)
CHyMLab> plot riverbasin 44
CHyM code (1)
CHyM code (2)
Modify CHyM code (0)
An example. Use of a different DEM.
Two different approaches:
1. Just wait… we are planning to include a more resolute DEM (100 m) for all the world
2. …be patient… (remember the first slide of this presentation)
2a. Before to edit any file, understand what you have to do
2b. Look the CHyM code and understand where to modify
2c. Implement the code
Modify CHyM code (1)
Your data:
LAT
LON
41.50 30.20
…..
…..
Array dem inside CHyM code
100.5
Calculate i,j
hsl (m)
100.5
….
Modify CHyM code (2)
Modify CHyM code (3)
Modify CHyM code (4)