Overview of the tracer code in RegCM

1
Overview of the tracer code in RegCM
Aerosols ( droplets, smoke particles, dust,
pollens, flying cats ) Gazeous phase, chemical
species
Tracers
Evolution of concentration (mixing ratio)
Qian and Giorgi, 1999
Transport
Removal terms
Primary Emissions
Physico chemical transformations
Strongly dependant on the nature of the tracer
2
Horizontal and vertical advection Horizontal and
vertical diffusion
derived from water vapor and cloud water (mm4
Anthes et al., 1987)
 Well-mixing approximation 
TCUM
Rq Tan et al., 2002 scheme ( work with
Kuo-scheme)
Not integrated yet
Mass flux / Grell, Emmanuel schemes
 Wet deposition 
Giorgi, and Chameides, 1986 Giorgi, 1989
Dry deposition
Fixed deposition velocities
Surface emissions
Input data
Chemistry
SO4--
SO2
Qian and Giorgi, 2001
3
Direct effect
Pronostic concentrations
Radiative transfer model ( CCM3 rad pack)
Optical properties of the tracer
Specific extinction
Fixed and characteristic of sulfates in our
example
Single scattering albedo
Assymetry parameter
The indirect effect (e.g. Qian and Giorgi, 1999)
is not taken into account in the present version
on the code
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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
webpagehttp//www.ictp.trieste.it/pubregcm/RegCM
3/patch.html and copy it in RegCM / Preproc
directory. Unzip and extract ( tar zxvf
Chemsrc.tar.gz) you should have a new Chemsrc
directory
5
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
6
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
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Post-processing with vis5D
. 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 .
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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