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	Becky Alexander Colette Heald Jeff Pierce Fangqun Yu
Aerosols Working Group email list	geos-chem-aerosols [at] g.harvard.edu
To subscribe to email list	Either Send an email to geos-chem-aerosols+subscribe [at] g.harvard.edu Or Go to the GEOS-Chem Aerosols Google Group Click on Subscribe to this group
To unsubscribe from email list	Either Send an email to geos-chem-aerosols+unsubscribe [at] g.harvard.edu Or Go to the GEOS-Chem Aerosols Google Group Click on the My Settings button Click on Leave this group

--Bob Y. (talk) 16:34, 21 August 2015 (UTC)

Current GEOS-Chem Aerosol Projects, alphabetized by institution (please add yours!)

User Group	Description	Contact Person	Date Added
Beijing/SUNY-Albany/L'Aquila	Representing GEOS-Chem in the AEROCOM intercomparisons	May Fu Fangqun Yu Gabriele Curci	28 Jul 2010
Columbia University	Multiphase SOA formation in GEOS-Chem	Faye McNeill	23 Apr 2015
Dalhousie	Decadal trends in PM2.5	Chi Li	13 Apr 2017
Dalhousie	Arctic aerosol number distributions	Betty Croft	13 Apr 2017
Dalhousie	Arctic black carbon	Junwei Xu	13 Apr 2017
Dalhousie	Metals in PM2.5	Junwei Xu	13 Apr 2017
Dalhousie	Interpreting SPARTAN to understand PM2.5 chemical composition	Crystal Weagle	13 April 2017
Dalhousie	Aerosol mass scattering efficiency	Robyn Latimer	13 April 2017
Harvard	Particulate sulfur via sulfur-formaldehyde (hydroxymethane sulfonate) chemistry in clouds	Jonathan Moch	14 Dec 2018
MIT/Harvard	Implementing MOSAIC aerosols into GEOS-Chem	Sebastian Eastham	11 May 2015
MIT	Developing a simulation of bioaerosol	Ruud Janssen	12 Apr 2017
MIT	Investigating spread in carbonaceous aerosol impacts from fires due to emissions uncertainty	Tess Carter	29 Apr 2019
MIT	Testing OA simulation schemes against suite of airborne observations	Sid Pai	29 Apr 2019
MIT	Exploring aerosol simulation against remote observations from ATom	Chloe Gao	29 Apr 2019
SUNY-Albany	Effects of size-resolved aerosol microphysics on aerosol radiative forcing and chemistry	Fangqun Yu Gan Luo	5 May 2015
SUNY-Albany	Combining Measurements and Model Simulations of Particle Size Distributions to Improve Our Understanding of Particle Formation and Growth	Fangqun Yu Gan Luo	4 May 2017
SUNY-Albany	Long-Term Trend of Particle Number Concentrations: Controlling Processes and Implications	Fangqun Yu Gan Luo	4 May 2017
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
University of Wollongong	Characterizing interannual variability of Australian dust export and deposition	Jesse Greenslade Jenny Fisher	23 April 2015
L'Aquila	Analysis of aerosol optical properties using FlexAOD	Gabriele Curci	16 Apr 2017
L'Aquila	AeroCom phase-3 intercomparisons: Biomass Burning, INSITU, Remote Sensing	Gabriele Curci	16 Apr 2017
L'Aquila	Direct and first indirect effect of anthropogenic dust	Gabriele Curci	16 Apr 2017
NIA / NASA LaRC	Radiative effects of aerosols versus clouds on key tropospheric oxidants	Hongyu Liu	5 May 2015
NIA / NASA LaRC	Sources and variability of tropospheric aerosols over the North Atlantic	Hongyu Liu	5 May 2015
UCLA	Improve black carbon simulations in GEOS-Chem; BC aging microphysics; BC-snow interaction; BC radiative properties;	Cenlin He	8 May 2015
UCLA	Black carbon emissions, simulations and its radiative effects over the Arctic	Ling Qi	8 May 2015
UCLA	Improve aerosol wet scavenging and dry deposition in GEOS-Chem	Ling Qi Cenlin He	8 May 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
v11-01	Jan 2017	GEOS-Chem species database	GEOS-Chem Support Team
v11-01	Jan 2017	Update DMS climatology to Lana	Tom Breider (Harvard)
v11-01	Jan 2017	Impaction scavenging for hydrophobic BC	Qiaoqiao Wang (Max Planck Institute)
v11-01	Jan 2017	Homogeneous IN removal	Qiaoqiao Wang (Max Planck Institute)
v11-01	Jan 2017	Density of OA update	Melanie Hammer (Dalhousie) Eloïse Marais (Harvard)
v11-01	Jan 2017	Improved dust size distribution scheme	Li Zhang (Colorado U.) Daven Henze (Colorado U.)
v11-01	Jan 2017	Addition of BrC UV absorption to address impacts on OH This feature is optional (default off)	Melanie Hammer (Dalhousie)
v11-01	Jan 2017	Acid uptake on dust aerosols This feature is optional (default off)	T. Duncan Fairlie (NASA/LARC)
v11-01	Jan 2017	Now treat DST2-DST4 as coarse mode in wet scavenging	T. Duncan Fairlie (NASA/LARC)
v11-01	Jan 2017	Online emission of marine primary organic aerosol (POA) This feature is optional (default off)	Brett Gantt (NCSU) Matthew Johnson (NASA Ames)
v11-01	Jan 2017	PM2.5 diagnostic	GEOS-Chem Support Team
v10-01	June 2015	The HEMCO emissions component now handles all emissions. Emissions for Sea salt aerosols and Mineral dust aerosols are now coded as HEMCO extensions.	Christoph Keller (fmr Harvard) GCST
v10-01	June 2015	Integrating a radiative transfer model into GEOS-Chem	David Ridley (MIT)
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

--Colette Heald 16:14, 8 May 2015 (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
Simplified description of uptake of SO2, nitric acid and sulfuric acid on mineral dust	Duncan Fairlie, Langley	Delivered to GCST Slated for inclusion into v10-02

--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

Issues / Topics for Discussion

Organic Aerosol Density (v.10-01)

This update was validated with 1-month benchmark simulation v11-01b and 1-year benchmark simulation v11-01b-Run0. This version was approved on 19 Aug 2015.

The organic aerosol density (1800 kg/m3) for calculating aerosol optical depth in aerosol_mod.F, based on Hess et al. (1997), is outdated and not representative of organic aerosols. The value is for a generic water soluble aerosol that could include sulfate, nitrate, SOA etc. Instead, we suggest GEOS-Chem users replace this with a density of 1300 kg/m3. There are numerous references that corroborate this value, or a value between 1200-1400 kg/m3. There are too many to list, but see for example p. 5174-5175 of Hallquist et al., ACP, 2007.

To make the change in aerosol_mod.F simply replace MSDENS(3) = 1800 with MSDENS(3) = 1300 in the RDAER subroutine. This leads to a 40% increase in organic carbon AOD.

Update by Eloise Marais (Harvard) and Melanie Hammer (Dalhousie).

--Emarais 21:06, 6 May 2015 (EDT)

Sedimentation of stratospheric aerosols

This update is slated for inclusion in GEOS-Chem v11-02.

Daniel Jacob wrote:

An issue has come up with our treatment of stratospheric aerosols. Seb Eastham applies sedimentation to sulfate and BC aerosols in his UCX code but he does not apply sedimentation to other aerosol species nor is his sedimentation code used in other GEOS-Chem simulations. It would be good to have consistency across aerosol types and across simulations (tropchem, RnPbBe...).

--Melissa Sulprizio (talk) 16:38, 20 August 2015 (UTC)