Aerosols Working Group
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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 |
| To unsubscribe from email list | Send email to geos-chem-aerosols-leave [at] seas.harvard.edu |
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 | Simulation of the absorbing aerosol index | Melanie Hammer | 26 Sep 2012 |
| Dalhousie | Aerosol microphysics simulation of AOD and PM2.5 | Arjya Sarkar | 26 Sep 2012 |
| Dalhousie | Arctic aerosol | Betty Croft | 25 Apr 2015 |
| 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 | Satellite-based estimates of Global PM2.5 | Aaron van Donkelaar | Jun 2010 |
| 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 | David Ridley | 22 Apr 2015 |
| MIT | Investigating uncertainty on aerosol physical & optical properties on AOD, radiative effects, and PM2.5 from space estimates | David 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 |
| SUNY-Albany | Effects of size-resolved aerosol microphysics on aerosol radiative forcing and chemistry | Fangqun Yu Gan Luo |
5 May 2015 |
| SUNY-Albany | Key processes controlling particle formation and growth in the atmosphere and implications | Fangqun Yu Gan Luo |
5 May 2015 |
| 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 long-term aerosol optical properties | Gabriele Curci | 05 May 2015 |
| 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 and understand its climatic effects | Cenlin He | 8 May 2015 |
| UCLA | Black carbon simulation and its radiative effects over the Arctic | Ling Qi | 8 May 2015 |
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) |
|
| Simplified description of uptake of SO2, nitric acid and sulfuric acid on mineral dust | Duncan Fairlie, Langley |
--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:
- Description of GEOS-Chem aerosol optics
- Aerosol optical properties update for v8-03-01
- 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:
- 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)
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)