GEOS-Chem model development priorities

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On this page we list the current priorities for GEOS-Chem development. This list is continuously updated based on code readiness and input from the Working Groups and the Steering Committee.

We also invite you to view our GEOS-Chem Support Team project management board on, which shows the current GCST workflow.

Priorities assigned to upcoming GEOS-Chem versions


This version is currently in development. See the GEOS-Chem 12 wiki page for details.


The items listed below are slated to be included in GEOS-Chem 12.2.0. This is a feature release which will be benchmarked with a 1-month benchmark simulation and a 1-year Rn-Pb-Be benchmark simulation.

Feature Submitted by Type Status
Features NOT affecting the full-chemistry simulation:
Common set of tracers in GEOS-Chem and GEOS Transport WG
  • A set of passive species will be added to the GEOS-Chem Rn-Pb-Be benchmark simulation. This will facilitate comparisons between GEOS-Chem "Classic" and/or GCHP vs. the NASA GEOS-DAS system.


The items listed below are slated to be included in GEOS-Chem 12.3.0. This is a feature release which will be validated with a 1-month benchmark simulation.

Feature Submitted by Type Status
Features affecting the full-chemistry simulation:
Update ISORROPIA from v2.0 to v2.2, in order to remove persistent noise in output Seb Eastham (Harvard) Science
  • Delivered to GCST (May 2017)
Update MODIS LAI fields for 2005-2016 using Yuan et al. (2011) Jenny Fisher (Wollongong)
Barron Henderson (US EPA)
  • Will require reworking of LAI regridding in GEOS-Chem Classic and pre-processing land map data
Updated PFT file for MEGAN Jenny Fisher (Wollongong)
Dylan Millet (UMN)
  • Delivered to GCST (May 2018)
Extend UCX into the mesosphere Sebastian Eastham (MIT) Science
OMI-based Volcanic emissions 2005-2012 Cui Ge (U. Iowa)
Jun Wang (U. Iowa)
  • Working with developers to obtain alternate data for Oct-Dec 2012.

Priorities not yet assigned to a particular version

The following items have been identified as priorities for GEOS-Chem, but have not yet been assigned to a particular GEOS-Chem version.

Ready to go in

Feature Submitted by Type Status
Emissions and surface fluxes updates
Carbon bottom up fluxes: anthro, ocean, land Kevin Bowman (JPL) Science Kevin Bowman wrote:
  • This is a a list of data archived from CMS-Flux that provides bottom up fluxes. These have been generated for the years 2010-2012 and are ready to go now. The key datasets are:
    • CMSFluxFire
    • CMSFluxFossilfuel
    • CMSFluxNEE
    • CMSFluxOcean
Aerosol updates
Sea salt aerosol alkalinity Qianjie Chen (UW)
Becky Alexander (UW)
Xuan Wang (Harvard)
  • UW version delivered to GCST (Nov 2017)
VBS SOA option Rokjin Park (SNU) Science
  • Code has been implemented in the ancient v9-01-02 version.
  • Bringing this up to the current SOA model (simple SOA, complex SOA) will likely involve significant effort.
Specialty simulation updates
AMAP/UNEP 2035 for Hg simulation Helene Angot (MIT) Science
  • Data is available, but has not been transferred to GCST yet
Oxidant fields from v10 for 2006-2012
  • 3D chemical source for CO2, CO
  • OH for tagged CO & CH4
Dylan Jones (UofT) Science
  • Will make data files available on ftp site
Africa nested-grid for GEOS-FP and MERRA-2 Eloise Marais (U. Birmingham) Science
  • Delivered to GCST (Dec 2017)
  • Could be implemented with Jiawei Zhuang's FlexGrid
West Africa nested-grid for GEOS-FP Mat Evans (York)
Eleanor Morris (York)
  • Could be implemented with Jiawei Zhuang's FlexGrid
Tagged sulfate simulation Becky Alexander (UW) Science
Arsenic simulation Shiliang Wu (MT) Science
GCHP updates
Structural updates
Benchmark of stratospheric simulation Dylan Jones (U. Toronto) Benchmarking
  • 1-yr benchmarks for GEOS-Chem v11-01d and later include comparisons with OSIRIS O3
  • Waiting on OSIRIS NO2 data
  • Waiting on comparisons with ACE-FTS data
Add total column O3 to benchmarks Chris Holmes (FSU)
  • Deferred until GEOS-Chem 12
  • Also note: GCST plans on migrating benchmark plotting code from IDL to Python in v11-03
ObsPack diagnostic as netCDF replacement for planeflight_mod.F Andy Jacobson (NOAA/ESRL) Structural
  • Delivered to GCST (May 2017)
Further structural updates to facilitate interfacing GEOS-Chem with external models (e.g. WRF, CAM, CESM) GCST Structural
  • Ongoing
Expansion of model capabilities
Archival of roughness length for temperature z0T GCST Met processing
  • Work has not yet begun

--Bob Yantosca (talk) 19:04, 2 August 2018 (UTC)

Almost there (< 6 months)

Item Author(s) Type Status
Transport updates
GEOS resolution & subgrid convection Karen Yu (Harvard) Science
  • To be installed by Bob Yantosca (Harvard), tested by Tailong He (Toronto)
  • Work to begin after GC 12.0.0 release
Chemistry updates
N2O5 hydrolysis updates Viral Shah (UW) Science
  • Defer until paper is submitted (Summer 2018)
  • Code from v10 (SMVGEAR) needs to be translated to v11 (FlexChem); this may take some effort
H2 chemistry in UCX Chris Holmes (FSU) Science
  • Defer until paper is submitted
  • Estimate Fall 2018 or sooner
Updated chlorine chemistry Xuan Wang (Harvard) Science
  • Defer until the paper is submitted
ND49 timeseries diagnostic for correcting ozone from the height of the lowest model level to 10m Katie Travis (MIT) Structural
  • Defer until the paper is submitted
OH + NO2 rate update Barron Henderson (EPA) Science
Script for checking N, C, etc. balance in chemistry mechanism Barron Henderson (EPA) Software Barron Henderson wrote:
  • The script for checking the carbon balance exists and works. Ideally, we would move some of the structures into the KPP files to codify them instead of storing them in the script itself. This would be less than 6 months. Click HERE for script
Aromatics and dicarbonyl chemistry William Porter (MIT)
Tzung-May Fu (PKU)
Document chemical mechanism in KPP file Mat Evans (York) Structural
Diurnal variability for NH3 Henze group Science Daven Henze wrote:
  • The FORTRAN code for implementing NH3 emissions diurnal variability is fairly straightforward. However, it involves calculation of some quantities that depend upon met fields in the future, and we’re unsure of how to accomplish this in a robust and elegant manner.
  • In particular, we need to know the aerodynamic resistance and surface temperature at every emission time step over the course of a time period X, where X is the time resolution of the NH3 livestock emissions inventory being used. This is typically monthly, but I could foresee future inventories having higher resolution, so maybe we want to consider this more generically.
  • One approach would be to pre-process this quantity at high resolution for all years, as is currently being done e.g. for dust emissions. Another would be to add code to read in this information from met files online, but this would add some i/o to the model.
Uptake of HNO3 onto coarse-mode sea salt Prasad Kasibhatla (Duke) Science
Photolysis of NITs Prasad Kasibhatla (Duke) Science
Emissions updates
Grid-independent lightning NOx emissions (3-hourly) Lee Murray (Rochester) Science
  • Data has not yet been transferred to GCST
Grid-independent dust emissions (hourly) David Ridley (MIT) Science
  • Data has not yet been transferred to GCST
Grid-independent biogenic emissions (hourly) Jintai Lin (PKU) Science
  • Data has not yet been transferred to GCST
Grid-independent sea salt emissions (hourly) Jintai Lin (PKU) Science
  • Data has not yet been transferred to GCST
EPA-derived BC/OA emissions over US (1990-2012) David Ridley (MIT)
Chi Li (Dalhousie)
  • Emissions are available but need to be formatted properly.
  • Could be ready by Fall-Winter 2018, depending on D. Ridley's availability
FINN biomass burning emissions for 2014-2016 Barron Henderson (US EPA) Science
  • Pending receipt of corrected data files
EPA NEI2011 Version EK Zitely Tzompa-Sosa (CSU)
Emily Fischer (CSU)
  • Estimate Late 2018 or sooner
GFAS biomass burning emissions Mat Evans (York) Science Mat Evans wrote:
  • For the sake of the documentation and the wiki I think we should replicate the standard benchmark year on our system, and then switch on the GFAS emissions instead of the GFED and then have the GFAS emissions distributed by hieight. We can do that and then prepare some plots for the documentation. Estimate summer 2018.
MASAGE inventory in HEMCO as default Fabien Paulot (NOAA/GFDL)
Amos Tai (CUHK)
  • MASAGE data is already available.
  • GCST would need assistance from the user community to prepare HEMCO configuration files such that we do not double-count agricultural NH3 from MASAGE and other inventories. This has been the main delay.
  • F. Paulot has left the GC community.
Non-agricultural NH3 for use with MASAGE Amos Tai (CUHK) Science
  • Waiting on data
Ocean ammonia emission inventory Fabien Paulot (NOAA/GFDL) Science
  • Data files delivered to GCST (Jan 2016)
  • Needs to be implemented via HEMCO, which is the primary delay
Injection height for fire emissions Juliet Zhu (CSU)
Emily Fischer (CSU)
  • Code was available in pre v9-02 (HEMCO)
  • Code may have been ported to v11-02a but this option was not activated
Surface fluxes and land usage updates
Land cover module: Harmonized biosphere-atmosphere exchange and implementing CLM or manual land cover change experiments Jeff Geddes (BU) Science
  • Has been added into v9-02 (pre-HEMCO)
  • Bringing this up to v11 will probably need significant effort
  • BU group/GCST will meet summer 2018 to discuss implementation
Online O3-LAI coupling in GEOS-Chem Amos Tai (CUHK) Science
Wet deposition updates
Wet deposition parameterizations: pH dependency, Henry's law coefficients, etc. Sarah Safieddine (MIT)
Wet scavenging in mixed-phase clouds Bo Zhang (NIA/NASA Langley) Science
  • Defer until paper is published
  • Estimate Fall 2018
Specialty simulation updates
Radon emission update Bo Zhang (NIA/NASA Langley) Science
  • Defer until paper is published
  • Estimate Fall 2018
PCB simulation Colin Thackray (Harvard)
Carey Friedman (formerly MIT)
Helen Amos (formerly Harvard)
New EDGAR sectoral inventory for Hg (1970-2012) Amanda Giang (MIT) Science
Archive GISS met fields from RCP scenarios for community Lee Murray (Rochester) Science
GCHP updates
New version of MAPL GMAO
Lizzie Lundgren (GCST)
Flux ingestion Sebastian Eastham (MIT) Science
Structural updates
Clean up SOA diagnostics GCST Structural
  • GCST has implemented many existing SOA diagnostics in netCDF
  • GCST would need help from the community to streamline these diagnostics
Calculation consistency throughout code: surface area, HGF (via species database) GCST Structural
Harmonizing Henry's Law coefficients across wet and dry deposition GCST Science
  • Work not started yet. Will need input from the community.
Expansion of model capabilities
CESM-GC offline coupling in standard model + benchmark Rokjin Park (SNU)
Daniel Rothenberg (MIT)
  • Rokjin Park says code is ready
  • Waiting on clarification in which version this is implemented in.

--Lizzie Lundgren (talk) 15:11, 29 June 2018 (UTC)

Over the horizon (6-12 months)

Item Author(s) Type Status
A snow NOx source from deep snowpack Maria Zatko (UW)
Becky Alexander (UW)
  • Delivered to GCST (Nov 2017)
  • Needs to be added as a HEMCO extension, but converting from ancient v9-01-01 code may take significant effort.
MEIC emissions over China (2000-2015) Lu Shen (Harvard)
Melissa Sulprizio (Harvard)
  • Defer until MEIC paper is published
GISS-GC (ICECAP/GCAP2) in standard model + benchmark Lee Murray (Rochester)
Eric Leibensperger (SUNY Plattsburgh)
Science Lee Murray replied:
  • "I would say 6-12 months to be safe, but the goal is to have it done by the end of summer 2018. There will actually be very minimal updates to GEOS-Chem; most of the updates are to modify the GISS model to output MERRA2-like data, to facilitate integration with GCHP and future updates to the CTM."
GISS-GC GCHP Lee Murray (Rochester)
Pengfei Liu (Harvard)
Yang Li (Harvard)
  • Rochester and Harvard groups are coordinating, to avoid duplication of effort
CESM-GC GCHP Seb Eastham (MIT) Science
  • Seb Eastham is now the lead developer.
  • Estimate late 2018 or early 2019; validation will take time
Additional modifications for FlexChem, including:
  • Rebuild the pre-built chemistry mechanisms (Standard, Tropchem, SOA-SVPOA) with Kppa
  • Add capability for custom chemistry mechanism by building KPP on-the-fly in GEOS-Chem
GCST Structural
  • Mike Long, who was the principal proponent behind these updates, has since left the GC community.
  • We are not sure who will take this over
Dynamic fire modeling/prediction Shiliang Wu (MNT) Science
Interannually varying ocean model BCs for Hg from ocean model Colin Thackray (Harvard) Science
PAH & PFCA simulations Peter Ivatt (York)
Mat Evans (York)
Noelle Selin (MIT)
Colin Thackray (Harvard)
CH4 in full chemistry simulation Seb Eastham (Harvard) Science
Standard future land use maps (PFT, LAI) for RCP/CMIP6 simulations Colette Heald (MIT)
Loretta Mickley (Harvard)
Archive GISS met fields from CMIP6 scenarios for community Lee Murray (Rochester) Science
Updates to cold-temperature deposition Lyatt Jaegle (UW) Science
Simple parameterization for CO2-O3 dependence of stomatal resistance Amos Tai (CUHK) Science
NH3 emissions over China Lin Zhang (PKU) Science
Using GEOS-Chem within GEOS-5 Loretta Mickley (Harvard) Science
Carbon cycle outputs in xCO2, xCH4 as a diagnostic Beata Bukosa (Wollongong)
Dylan Jones (UofT)
Seasonal EMEP emissions back to 1980 Mat Evans (York) Science
Updates to NO2 dry deposition Brian Boys (Dalhousie) Science
APM update and integration with most recent GEOS-Chem version Gan Luo (SUNY Albany) Structural
Cosmogenic tracer production Lee Murray (Rochester) Science
Explore resolution-consistent dust emissions
  • Make high-res concentrations or mass fluxes available offline, implement in met field processing
David Ridley (MIT)
Nested Model WG
Dust emissions at nested-grid resolutions Yuxuan Wang (U. Houston)
Jun Wang (U. Iowa)
  • Check for overlap with resolution-consistent dust emissions above
Update SO2 scavenging in convective updrafts for consistency Duncan Fairlie (NASA/LARC) Science
Sea salt emission from sea ice Jiayue Huang (UW) Science
Uniformity of units GCST Structural Lizzie Lundgren wrote:
  • We are not planning on resuming work to unify units in GEOS-Chem anytime soon. Any changes to units in the near future would be for better compatibility with other models, although none are currently planned. However, user consensus on preferred units would still be helpful to move the conversation forward.

--Bob Yantosca (talk) 19:42, 24 May 2018 (UTC)

Longer term (12-24 months)

Item Author(s) Type Status
GCHP stretched grid Jiawei Zhuang (Harvard) Science
1/8 degree nested-grid simulations with GEOS-FP Nested Model WG Science
  • Wait for more interest
Embedding GEOS-Chem into CESM Jean-Francois Lamarque (NCAR) Science
  • NOTE: Seb Eastham is already working on this
Adjoint of carbon cycle simulation in GCHP Kevin Bowman (JPL) Science
Isoprene chemistry v2 (new Caltech update) Kelvin Bates (Caltech) Science
Contemporary land cover: developing historical and updated GEOS-Chem land cover maps based on satellite remote sensing Jeff Geddes (BU) Science
Farquhar-Ball-Barry model to calculate stomatal resistance Amos Tai (CUHK)
Jeff Geddes (BU)
Impacts of chemistry on ecosystem/carbon cycle Kevin Bowman (JPL)
Anthony Bloom (JPL)
Improved lightning emission scheme Lee Murray (Rochester) Science
Resolution-independent lightning NOx Lee Murray (Rochester) Science
Bidirectional NH3 emissions Juliet Zhu (CSU) Science
Country-based weekday/weekend variability for EDGAR 4.2 Lee Murray (Rochester)
Christoph Keller (Harvard)
Update keytone photolysis Jared Brewer (CSU)
Emily Fischer (CSU)
Small alkyl nitrates Jenny Fisher (Wollongong) Science
YIBS-GC chemistry-biosphere-fire coupling Loretta Mickley (Harvard)
Xu Yue (IAP)
Nitrogen-LAI coupling Lin Zhang (PKU)
Amos Tai (CUHK)
Implementing humidity/VPD dependence of dry deposition Jennifer Murphy (U. Toronto) Science
SO2 wet scavenging Duncan Fairlie (NASA Langley) Science
Heterogeneous sulfate production Lin Zhang (PKU)
Becky Alexander (UW)
Yuxuan Wang (U. Houston)
MOSAIC implementation Sebastian Eastham (Harvard) Science
Particle size climatology Fangqun Yu (SUNY Albany) Science
Sea salt/dust size distribution David Ridley (MIT)
Colette Heald (MIT)
Updates to GTMM Rebecca Stern (Harvard) Science
Tracer transport ocean Chris Holmes (FSU) Science
Include Hg in full chemistry simulation Noelle Selin (MIT) Science
Goddard seasonal weather prediction in GCHP Kevin Bowman (JPL) Science
Climate index diagnostics (drought, etc.) Chemistry-ecosystems-climate WG Structural
Joint CO/CO2/CH4 simulation Nicholas Deutscher (U. Wollongong) Science
Carbon coupling: oceans and terrestrial models Chris Holmes (FSU) Science
  • Ocim-pure physical transport, ECCO-Darwin ocean biogeochemistry
DMS oxidation scheme updating Qianjie Chen (UW)
Chemistry WG
Limiting NH3 uptake due to OA Rachel Silvern (Harvard) Science

--Bob Yantosca (talk) 15:32, 23 May 2018 (UTC)