Aerosols Working Group

All users interested in the GEOS-Chem aerosol simulations are encouraged to subscribe to the aerosols email list (click on the link in the contact information section below).

Information on existing projects and future developments in aerosols will be posted here. We encourage user groups to keep their information up-to-date.

Contact information

Aerosols Working Group Co-Chairs	Colette Heald, Jeff Pierce
Aerosols Working Group email list	geos-chem-aerosols [at] seas.harvard.edu
To subscribe to email list	Send email to geos-chem-aerosols-join [at] seas.harvard.edu
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Current GEOS-Chem Aerosol Projects, alphabetized by institution (please add yours!)

User Group	Description	Contact Person	Date Added
Beijing/SUNY	Representing GEOS-Chem in the AEROCOM intercomparisons	May Fu Fangqun Yu	28 Jul 2010
Dalhousie/Tsinghua	Historical trends in Asian PM2.5 and emissions	Guannan Geng	26 Sep 2012
Dalhousie	Simulation of the absorbing aerosol index	Melanie Hammer	26 Sep 2012
Dalhousie	Diurnal variation in North American aerosol	Andrew Morrow	26 Sep 2012
Dalhousie	Sensitivity of global PM2.5 to sources	Colin Lee	26 Sep 2012
Dalhousie	Aerosol microphysics simulation of AOD and PM2.5	Arjya Sarkar	26 Sep 2012
Dalhousie	Aerosol scavenging, nuclear accident simulation (137-CS, 133-XE)	Betty Croft	03 Jan 2013
Dalhousie	Satellite-based estimates of Asian PM2.5	Junwei Xu	26 Sep 2012
Dalhousie	Assimilation of CALIOP vertical profiles	Colin Lee	5 Dec 2013
Dalhousie	Simulation of heavy metals in PM	Farhan Khan	5 Dec 2013
Harvard	Irreversible uptake of isoprene SOA; estimate of organic aerosol yields with satellite observations	Eloise Marais	27 April 2014
MIT	Examining decadal trends in organic aerosol	Dave Ridley	22 Apr 2015
MIT	Investigating uncertainty on aerosol physical & optical properties on AOD, radiative effects, and PM2.5 from space estimates	Dave Ridley	22 Apr 2015
MIT	Integrating the reactive carbon budget in GEOS-Chem	Sarah Safieddine	22 Apr 2015
MIT	Investigating Variability in Ammonia and Impacts on Inorganic PM formation	Luke Schiferl	22 Apr 2015
MIT	Investigating the impact of land use change on atmospheric composition	Sam Silva	22 Apr 2015
MIT	Developing a simulation of brown carbon	Xuan Wang	22 Apr 2014
MIT	Developing a scheme to describe the aging of organic aerosol	Qi Chen	8 Apr 2013
MIT/Dalhousie	Developing a flexible land use module for GEOS-Chem and investigating the impacts of forest mortality on air quality in the United States	Jeff Geddes	22 Apr 2015
MIT/CSU	Characterizing the uncertainties in PM2.5 derived from satellite observations	Bonne Ford	22 Apr 2015
NASA LaRC	transpacific transport of dust and sulfate; composition of Asian upper tropopause aerosol layer (ATAL).	Duncan Fairlie	10 Apr 2013
SNU	Implement the VBS method in GEOS-Chem for SOA	Rokjin Park Dusung Jo	28 Sep 2012
SNU	Siberian forest fire aerosols and climatic effects	Rokjin Park Seungeun Lee	28 Sep 2012
UW	Sources of sea salt aerosol in polar regions: Blowing snow and Frost flowers	Jiayue Huang Lyatt Jaeglé	22 Apr 2015
UW	Sea salt aerosols and their effects on global tropospheric chemistry	Lyatt Jaeglé Jiayue Huang	22 Apr 2015
UW	Sulfate formation via oxidation of SO2 by hypohalous acids (e.g., HOBr)	Becky Alexander Qianjie Chen	22 April 2015

Recent GEOS-Chem updates related to aerosols

We have added the following updates pertaining to aerosols to recent GEOS-Chem versions:

Version	Released	Description	Contact
v9-02	Mar 2014	Expansion of SOA option (SOA + nonvolatile POA)	Havala Pye (formerly Caltech, now EPA)
v9-02	Mar 2014	Cloud water pH for sulfate formation	Becky Alexander (U. Washington)
v9-02	Mar 2014	Better representation of OC growth with RH and correction to sulfate optics	David Ridley (MIT) Randall Martin (Dalhousie)
v9-02	Mar 2014	Bug fix in jv_spec_aod.dat for dust species	Gabriele Curci (U. L'Aquila)
v9-02	Mar 2014	Update molecular weight of sea salt tracers	Colette Heald (MIT)
v9-01-03	Sep 2012	Dust submicron size distribution for optics	Dave Ridley, CSU
v9-01-03	Sep 2012	Modifications to sea salt emissions and dry deposition	Lyatt Jaegle and Becky Alexander, U Washington
v9-01-03	Sep 2012	Various updates to wet deposition to impact aerosol simulation, see Wet Deposition Further Updates	Qiaoqiao Wang, Harvard
v9-01-02	Nov 2011	Implementation of APM aerosol microphysics model	Fangqun Yu, SUNY Albany Gan Luo, SUNY Albany
v9-01-02	Nov 2011	Removing inconsistencies in aerosol diagnostics	Sungshik Patrick Kim, Harvard
v9-01-02	Nov 2011	Updated aerosol dry deposition velocities over snow and ice surfaces	Jenny Fisher, Harvard
v9-01-02	Nov 2011	Added seasonality to Streets NH3 emissions over Asia	Jenny Fisher, Harvard
v9-01-01	Jun 2011	FlexAOD post-processing tool for the community	Gabriele Curci, University of l'Aquila

--Melissa Sulprizio 11:14, 17 January 2014 (EST)

On-going Aerosol Working Group Developments

We plan to add these aerosol-related updates to GEOS-Chem in the next few releases:

Update	Authors	Planned release
Integrating a radiative transfer model into GEOS-Chem	Colette Heald (MIT) David Ridley (MIT) Karen Cady-Pereira (AER) Matt Alvarado (AER)	Delivered to GCST Slated for inclusion into v10-01
Simplified description of uptake of SO2, nitric acid and sulfuric acid on mineral dust	Duncan Fairlie, Langley	Delivered to GCST Slated for inclusion into v10-01

--Bob Y. 15:05, 25 April 2014 (EDT)

Future Development Priorities

These are topics which were raised at IGC6 as future updates & development priorities for GEOS-Chem which have not yet been incorporated into the standard code:

Update	Authors	Priority
Addition of effective wind speed to met fields for consistent resolution dust/sea salt emissions	Jeff Pierce (CSU) David Ridley (MIT) GCST	medium
Addition of deposition observations to aerosol benchmark	Colette Heald (MIT)	low
dust simulation expansion (tagged simulation, oxalate, P, Fe chemistry)	Matthew Johnson (NC State)	low
DMS oxidation scheme updating	TBD	low
Investigation of how aerosol water is treated in PM comparisons (ISORROPIA vs. hygroscopic growth curves)	TBD	low
APM capability for nested grid	Fangqun Yu (SUNY Albany)
TOMAS capability for nested grid	Jeff Pierce (Dalhousie)
Tagged sulfate and nitrate simulation	Becky Alexander (U. Washington)
Improved dust simulation in nested-grid model	Rokjin Park (Seoul National University)

--Bob Y. 15:04, 25 April 2014 (EDT)

Aerosol optical properties

Please visit our aerosol optical properties wiki page for more information about:

1. Description of GEOS-Chem aerosol optics
2. Aerosol optical properties update for v8-03-01
3. Aerosol optical properties at high spectral resolution

Here is a list of updates that were considered when this was last reviewed in 2010 (2, 4 and 5 are included in the v8-03-01 update):

Proposed Update (include information on old values if known)	Reference	Contact
Account for absorption in the 300-500 nm range by OC, which may be greater than presently treated. Currently we have OC ss albedo in this range being > 0.95, though it may be lower than 0.85.	Barnard et al, 2008	Daven Henze
Expand Mie table to include more wavelengths. Most literature values compare at 500 or 550 nm. Current GC lookup table includes 400, then 600. A wider range is also necessary for integrating to get total SW flux; something greater than 1500 perhaps?	Martin et al, 2004	Daven Henze
Consider using the water content of the fine mode aerosol calculated in the aerosol thermodynamic module rather than hygroscopic growth curves to estimate wet particle effective radius.	N/A	Daven Henze
Consider changing the "default" AOD diagnostic wavelength from 400 nm to 550nm (for matching with MODIS & CALIPSO)	N/A	Colette Heald
Treat the radius of hydrophylic organic aerosol similar to that of sulfate. This is based on observations that organic aerosol and sulfate are often internally mixed. Should we consider something similar for black carbon?	Rupkheti et al., 2007	Randall Martin

Additional updates to aerosol optics since v8-03-01:

Update	Version Number	Contact
Overhaul of AOD diagnostics	v9-01-02	Patrick Kim (Harvard)
Dust submicron size distribution for optics	v9-01-03	David Ridley (CSU, now MIT)
Bug fix in jv_spec_aod.dat for dust species	v9-02	Gabriele Curci (l'Aquila)
Update jv_spec.dat and jv_spec_aod.dat with better representation of OC growth with RH and correction to sulfate optics	v9-02	Dave Ridley (MIT) and Randall Martin (Dalhousie)

Related Topics

• Aerosol emissions
• Aerosol microphysics simulations:
  • with APM
  • with TOMAS
• Aerosol-only simulation
• Aerosol thermodynamical equilibrium
• Carbonaceous aerosols
• Mineral dust aerosols
• Secondary organic aerosols
• Sea salt aerosols
• Sulfate aerosols
• ISORROPIA II
• Photolysis mechanisms in GEOS-Chem