Aerosol-only simulation: Difference between revisions
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--[[User:Bmy|Bob Y.]] 17:12, 3 March 2011 (EST) | --[[User:Bmy|Bob Y.]] 17:12, 3 March 2011 (EST) | ||
== More Information == | == More Information == | ||
Revision as of 15:45, 8 August 2011
On this page we describe the aerosol-only (a.k.a. offline aerosol) simulation.
Description
The aerosol simulation is an offline simulation for aerosol tracers only. It uses archived monthly mean OH, NO3, O3 and total nitrate concentrations archived from a previous full-chemistry simulation (more on that below), as well as production and loss rates for H2O2. This simulation does not provide "tagged" capabilities, but reduces the suite of tracers from full chemistry.
Assumptions
- OH concentrations are taken from a previously run full chemistry simulation. The default is from a much earlier version of the model, when OH thought to be more realistic. The standard code uses OH from version 5-07-08, with GEOS3 meteorology.
- O3, NO3 and total nitrate (HNO3+NIT) concentrations, as well as production rates and photolysis rates for H2O2 are taken from a previously run full chemistry simulation. The current default fields were produced from a GEOS-4, v7-02-03 simulation. These files are generally located in the sulfate_sim_200508/offline/ directory in your GEOS-Chem data directories.
Practicalities
As with all other Offline chemistry simulations, the GEOS-Chem user community shall be responsible for the scientific content and validation of the aerosol-only simulation.
Tracer list
In a complete aerosol-only simulation there are 31 tracers (see input.geos below).
The offline aerosol is simulation type 10. For a full set of aerosol tracers (based on the 59-tracer full-chemistry SOA simulation), the input.geos should look like this:
Type of simulation : 10 Number of Tracers : 31 Tracer Entries -------> : TR# Name g/mole Tracer Members; () = emitted Tracer #1 : 1 DMS 62.00 Tracer #2 : 2 SO2 64.00 Tracer #3 : 3 SO4 96.00 Tracer #4 : 4 MSA 96.00 Tracer #5 : 5 NH3 17.00 Tracer #6 : 6 NH4 18.00 Tracer #7 : 7 NIT 62.00 Tracer #8 : 8 H2O2 34.00 Tracer #9 : 9 BCPI 12.00 Tracer #10 : 10 OCPI 12.00 Tracer #11 : 11 BCPO 12.00 Tracer #12 : 12 OCPO 12.00 Tracer #13 : 13 ALPH 136.23 Tracer #14 : 14 LIMO 136.23 Tracer #15 : 15 ALCO 142.00 Tracer #16 : 16 SOG1 150.00 Tracer #17 : 17 SOG2 160.00 Tracer #18 : 18 SOG3 220.00 Tracer #19 : 19 SOG4 130.00 Tracer #20 : 20 SOG5 150.00 Tracer #21 : 21 SOA1 150.00 Tracer #22 : 22 SOA2 160.00 Tracer #23 : 23 SOA3 220.00 Tracer #24 : 24 SOA4 130.00 Tracer #25 : 25 SOA5 150.00 Tracer #26 : 26 DST1 29.00 Tracer #27 : 27 DST2 29.00 Tracer #28 : 28 DST3 29.00 Tracer #29 : 29 DST4 29.00 Tracer #30 : 30 SALA 36.00 Tracer #31 : 31 SALC 36.00
This list can be reduced by turning off any aerosol species (eg. SOA, dust, SS, etc). You may also run without the secondary organic aerosols (ALPH, LIMO, ALCO, SOG{1,2,3,4,5}, SOA{1,2,3,4,5}) if you wish (but we recommend that you use them).
Run directories
We recommend that you create the run directory for your aerosol-only (a.k.a offline aerosol simulation) from one of the GEOS-Chem full-chemistry run directories.
First, use Git to download one of the full-chemistry run directories for the simulation with secondary organic aerosols.
Next, edit the TRACER MENU section of the input.geos file so that only the aerosol tracers are listed.
Next, create a new restart file that contains only the aerosol tracers. The easiest way to do this is with GAMAP. Start GAMAP and Then all you’d have to do is change the number of tracers in “input.geos”. You could also create a new restart file with GAMAP. Start GAMAP with:
gamap, file=’restart.4x5.geos5.2004010100', 'IJ-AVG-$'
Then pick the tracers you want to save, and type
S25-56 # this is DMS .. SALC in the 59-tracer SOA fullchem file
and when prompted for an output file name, type
restart.4x5.geos5.2004010100.aer_only
and press "OK". Make sure to add this restart file name to the SIMULATION MENU section of your input.geos file.
You may also need to create an SOA restart file which contains the concentrations of various short-lived secondary organic aerosol quantities.
Please also see the following references:
- GEOS-Chem User's Guide: Chapter 5: GEOS-Chem run directories
- GEOS-Chem User's Guide: Chapter 6.1.6: Checklist for offline aerosol chemistry simulation
--Bob Y. 17:12, 3 March 2011 (EST)
More Information
For more information, see the GEOS-Chem manual pages about offline aerosols:
http://acmg.seas.harvard.edu/geos/doc/man/chapter_6.html#6.1.6 http://acmg.seas.harvard.edu/geos/doc/man/appendix_1.html#A1.8