Transcript Document

Overview of the tracer code in RegCM
Tracers
Aerosols ( droplets, smoke particles, dust, pollens, flying cats …)
Gazeous phase, chemical species
Qian and Giorgi, 1999
Evolution of concentration
(mixing ratio)

 V    FH  FV  TCUM  S   Rw,ls  Rw,cum  Ddep   Q p  Ql
t
Transport
Primary
Emissions
Removal
terms
Physico – chemical
transformations
Strongly dependant on the nature of the tracer
Horizontal and vertical advection
derived from water vapor and cloud water
Horizontal and vertical diffusion
(mm4 Anthes et al., 1987)
TCUM
« Well-mixing approximation »
Rq :
Tan et al., 2002 scheme ( work with Kuo-scheme)
Not integrated yet
Mass flux / Grell, Emmanuel schemes
Rw,ls    f sol (  ) 
« Wet deposition »
Giorgi, and Chameides, 1986
Giorgi, 1989
1  exp(t /  w,ls )
Rw,cum    f cum  f sol (  ) 
t
1  exp(t /  w,cum )
t
Dry deposition
Fixed deposition velocities
Surface emissions
Chemistry
Input data
SO4--
SO2
Qian and Giorgi, 2001
Direct effect
Pronostic concentrations
Radiative transfer model
Optical properties of the tracer
( CCM3 rad pack)
Specific extinction
Single scattering albedo
Fixed and characteristic
of sulfates in our example
Assymetry parameter
The indirect effect (e.g. Qian and Giorgi, 1999) is not taken into account
in the present version on the code
One « generic tracer »
Application :
Source defined from GEIA 97 (BC)
No chemistry
Direct effect only (diffusive properties)
….Before the simulation …..
Go to the RegCM / Preproc directory and remove the Chemsrc directory
rm –R Chemsrc
Download Chemsrc.tar.gz file from the webpage
http://www.ictp.trieste.it/~pubregcm/RegCM3/patch.html
and copy it in RegCM / Preproc directory.
Unzip and extract ( tar zxvf Chemsrc.tar.gz)
… you should have a new Chemsrc directory …
PATCH
Preproc step
Prepare : Terrain / ICBC for june 1997
(with the same domain as practise run)
1997060100
1997070100
………
Preparation of tracer sources
(interpolation of a global data set on the RegCM domain)
go to RegCM/Preproc/Chemsrc
Run the chsrfem.x script
It generates the file CHEM-BC97 in RegCM/Input directory
Simulation with tracers
Create a new run directory for running tracer simulations
Ex : RegCM / PractiseTrac
Copy the regcm.x and regcm.in from the Regcm / Commons
directory in the PractiseTrac directory
Link the emission file into this run directory
ln –sf ../Input/CHEM-BC97 .
Run the model with tracer options
edit regcm.in
5 days 1997060100 –
1997060500
Post-processing with vis5D
PATCH
…. Before the post processing ….
Remove the RegCM/Postproc-v5d directory
Download the Postproc-v5d.tar.gz file and extract
it in the RegCM directory
Go to the directory Postproc-v5d and link here the simulation
output fields :
ln –sf ../ PractiseTrac /output/ATM.1997060100 .
ln –sf ../ PractiseTrac /output/CHE.1997060100 .
ln –sf ../ PractiseTrac /output/RAD.1997060100 .
In Postproc-v5d
Edit the postpv5d.in and set the control parameters
Edit the postpv5d.param and set the run parameters
Execute the postpv5d.x
… it generates the P_OUT.v5d file ( if pressure grid)
Execute vis5d P_OUT.v5d to visualise the file