Photolysis mechanism: Difference between revisions

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The following photolysis mechanisms have been implemented in official releases of GEOS-Chem:
The following photolysis mechanisms have been implemented in official releases of GEOS-Chem:


=== FAST-J ===
=== FAST-JX v7.0 ===


The [[FAST-J photolysis mechanism]] was used in GEOS-Chem versions prior to [[GEOS-Chem v10-01]].
The [[FAST-JX v7.0 photolysis mechanism]] is the newest version of the FAST-J software.  It was incorporated into [[GEOS-Chem v10-01]] by Sebastian Eastham (MIT) and the [[GEOS-Chem Support Team]], along with the [[UCX chemistry mechanism|UCX stratospheric-tropopsheric chemistry mechanism]].


FAST-J is being currently being replaced by the [[FAST-JX v7.0 photolysis mechanism]], which will ship with the standard [[GEOS-Chem v10-01]] public release (slated for late 2014).
--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 17:06, 16 November 2016 (UTC)


--[[User:Bmy|Bob Y.]] 11:58, 20 May 2014 (EDT)
=== FAST-J ===
 
=== FAST-JX v7.0 ===
 
The [[FAST-JX v7.0 photolysis mechanism]] is the newest version of the FAST-J software.  It is being incorporated into [[GEOS-Chem v10-01]] by Sebastian Eastham (MIT) and the [[GEOS-Chem Support Team]].  This is being done concurrently with the introduction of the [[UCX chemistry mechanism|UCX stratospheric-tropopsheric chemistry mechanism]] into GEOS-Chem.


--[[User:Bmy|Bob Y.]] 11:58, 20 May 2014 (EDT)
The [[FAST-J photolysis mechanism]] was used in GEOS-Chem versions prior to [[GEOS-Chem v10-01]].  It has since been replaced by [[FAST-JX v7.0 photolysis mechanism]].


=== VOC photolysis ===
--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 17:07, 16 November 2016 (UTC)
Here I summarize VOC photolysis in Fast-JX v7.0
{| border="1" cellspacing="0" cellpadding="5"
|-bgcolor="#cccccc"
! width="250px" |Old reaction
! width="100px" |Old rate
! width="250px" |New reaction
! width="150px" |New rate
! width="300px" |Note
|-valign="top"
| CH2O = HO2 + HO2 + CO ||  ||same ||Significant increase by 10% to 20% || channel a
|-
| CH2O = H2 + CO  ||  ||same ||increase by 6% to 15% || channel b
|-
| PAN = 0.6MCO3 + 0.6NO2 + 0.4MO2 + 0.4NO3  ||  ||same ||  || JPL2010 suggests two channels, in contrast to FastJX-v7.0, branching ratio follows IUPAC
|-
| ALD2 = MO2 + HO2 + CO||  ||same ||  ||
|-
| ALD2 = CH4 + CO ||  ||same ||  ||
|-
| GLYX = 0.5H2 + CO + 0.5CH2O + 0.5CO ||  ||GLYX = H2 + 2CO  <br> GLYX = CH2O + CO || Pressure dependence is now included  ||now 3 channels
|-
| GLYX = 2.0CO + 2.0HO2||  ||same ||Pressure dependence is now included  ||
|-
| MACR = CO + HO2 + CH2O + MCO3 <br> branching ratio = 0.5 ||  ||same ||  ||
|-
| MACR = MAO3 + HO2 <br> branching ratio = 0.5||  ||remove this channel ||  ||suggested by IUPAC, also consistent with Fast-JX v7.0
|-
| MVK = PRPE + CO <br> branching ratio = 0.6||  || ||  ||
|-
| MVK = MCO3 + CH2O + CO + HO2 <br> branching ratio = 0.2||  || ||  ||
|-
| MVK = MO2 + MAO3<br> branching ratio = 0.2||  ||MVK = MO2 + RCO3 ||  ||this channel was removed in FJX v7.0, but it shouldn't according to IUPAC. MAO3 is changed to RCO3 for carbon balance.
|-
| GLYC = CH2O + 2.0HO2 + CO ||  ||same ||  ||
|-
|  ||  ||GLYC = CH3OH + CO ||  ||two more channels were added in FJX v7.0, but IUPAC only recommends this one
|-
| MEK = 0.85MCO3 + 0.85ETO2 + 0.15MO2 + 0.15RCO3  ||  ||same ||  ||two channels are merged into one reaction
|}
--[[User:Jmao|Jmao]] 15:54, 20 May 2014 (EDT)


== Photolysis mechanisms used in research versions of GEOS-Chem ==
== Photolysis mechanisms used in research versions of GEOS-Chem ==

Latest revision as of 19:47, 2 January 2019

Here we link to pages describing the various versions of the FAST-J and FAST-JX photolysis mechanisms used in GEOS-Chem.

Photolysis mechanisms used in standard GEOS-Chem versions

The following photolysis mechanisms have been implemented in official releases of GEOS-Chem:

FAST-JX v7.0

The FAST-JX v7.0 photolysis mechanism is the newest version of the FAST-J software. It was incorporated into GEOS-Chem v10-01 by Sebastian Eastham (MIT) and the GEOS-Chem Support Team, along with the UCX stratospheric-tropopsheric chemistry mechanism.

--Bob Yantosca (talk) 17:06, 16 November 2016 (UTC)

FAST-J

The FAST-J photolysis mechanism was used in GEOS-Chem versions prior to GEOS-Chem v10-01. It has since been replaced by FAST-JX v7.0 photolysis mechanism.

--Bob Yantosca (talk) 17:07, 16 November 2016 (UTC)

Photolysis mechanisms used in research versions of GEOS-Chem

The following photolysis mechanisms have been used in non-standard research versions of GEOS-Chem:

FAST-JX v6.2

The FAST-JX v6.2 photolysis mechanism was implemented into several research versions of GEOS-Chem by Jingqiu Mao (Princeton). But this version of FAST-J was never incorporated into the standard GEOS-Chem model.

--Bob Y. 11:58, 20 May 2014 (EDT)

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