Transport Working Group
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|Transport Working Group Co-Chairs|
|Transport Working Group email list||geos-chem-transport [at] g.harvard.edu|
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Current GEOS-Chem Transport Projects (please add yours!)
|User Group||Description||Contact Person|
|U. Toronto||Assessing impact of transport biases on methane simulation and applying weak constraint 4D-Var to correct them||Ilya Stanevich|
|U. Toronto||Characterizing model transport errors using weak constraint 4D-Var||Martin Keller|
|U. Toronto||Quantifying the impact of errors in PBL mixing on CO2||Wei Lu|
|Harvard||Examining the effect of grid resolution on vertical transport and convective mass fluxes||Karen Yu|
|Harvard||Quantifying the impact of numerical diffusion on plume transport and comparing to observed atmospheric diffusion||Sebastian D. Eastham|
|Harvard||Assessing the co-benefits of increasing vertical and horizontal grid resolutions for tracer transport||Jiawei Zhuang|
|Dalhousie||Implementation of a new PBL mixing scheme||Aaron van Donkelaar|
|NIA / NASA Langley||Constraints on Precipitation Scavenging and Transport of Soluble Trace Species From Airborne and Surface Radionuclide (222Rn, 210Pb, 7Be, 10Be) Observations||Bo Zhang Hongyu Liu|
|Add yours here!|
Current GEOS-Chem Transport Issues
Text to be added
Common set of tracers in GEOS-Chem and GEOS
The transport Working Group has proposed implementing additional tracers in GEOS-Chem for benchmarking purposes and diagnosing transport in GEOS-Chem compared to GEOS-5.
Honygyu Liu wrote:
- Andrea and I would like to seek your comment on the effort needed to implement additional tracers in GCC and GCHP. See below for the list of tracers in GEOS that Andrea sent earlier.
- It would be straightforward to implement all these tracers in GCHP. Per Andrea, all we need to do is to download some additional code (called the tracer gridded component "Tracer_GridComp" in GEOS).
- If we want the same tracer suites in GCC (e.g., an extension of current radionuclide tracers, simulation type "1") as in GCHP, how much effort would it be? Is there any practical reason that a reduced number of tracers is preferred in GCC?
Bob Yantosca replied:
- It looks as if most of these are passive species with a fixed atmospheric lifetime, right? If so, then it is very straightforward to add these to any GEOS-Chem simulation. See our instructions for adding passive species to GEOS-Chem.
- So basically in the passive species menu of input.geos you would list the names of each passive species, its default concentrations, and atmospheric lifetime is. If the species has an emissions flux, you can specify that with a corresponding entry in the HEMCO_Config.rc file, as described on the wiki.
- I think the only modification we might need to make is that you are currently limited to 20 passive species but that is easy to extend by just changing a parameter value.
List of tracers in GEOS
17 GMI tracers: https://gmi.gsfc.nasa.gov/uploads/files/gmi_tracersuite.pdf
Additional Tracers in GEOS - used in part to get an age spectrum
# Name Units Long Name # ----- ------ -------------------------------- nh_5 'mol mol-1' Northern Hemisphere 5 day tracer nh_50 'mol mol-1' Northern Hemisphere 50 day tracer sh_5 'mol mol-1' Southern Hemisphere 5 day tracer sh_50 'mol mol-1' Southern Hemisphere 50 day tracer ntr_5 'mol mol-1' Northern Hemisphere Subtropical 5 day tracer ntr_50 'mol mol-1' Northern Hemisphere Subtropical 50 day tracer str_5 'mol mol-1' Southern Hemisphere Subtropical 5 day tracer str_50 'mol mol-1' Southern Hemisphere Subtropical 50 day tracer tr_5 'mol mol-1' Tropical 5 day tracer tr_50 'mol mol-1' Tropical 50 day tracer e90 'mol mol-1' Constant emission 90 day tracer e90_n 'mol mol-1' Constant emission Northern Hemisphere 90 day tracer e90_s 'mol mol-1' Constant emission Southern Hemisphere 90 day tracer st80_25 'mol mol-1' Stratospheric source 25 day tracer aoa_nh 'days' Age of air tracer (Northern Hemisphere surface source) ::
and a few others
CH3I 'mol mol-1' Methyl iodide st80_25 'mol mol-1' Stratosphere source 25 day tracer CO_50_na 'mol mol-1' Anthro CO North America 50 day tracer
Chris Holmes wrote:
- Another tracer suggestion: I like and use the "origin" tracers defined by Clara Orbe et al. (2013). These tracers give the fraction of air that that originates in specified source regions.
- In addition to diagnosing transport, I think the tracers will be useful as templates for users to modify for their own purposes (e.g. customizing source regions). For that reason, a comprehensive set of tracers would be useful, if they can be optional.
- Orbe, C., M. Holzer, L. M. Polvani, and D. Waugh (2013), Air-mass origin as a diagnostic of tropospheric transport, J. Geophys. Res. Atmos., 118, 1459–1470, doi:10.1002/jgrd.50133.