Grid-independent emissions
These emissions were be implemented in GEOS-Chem 12.4.0.
Overview
The grid-independent emissions were identified as a priority during the development of GCHP, which uses cubed-sphere grids instead of the traditional lat-lon grids used by GEOS-Chem "Classic". As such, emissions that utilized resolution-dependent scale factors (e.g. dust and lightning) posed a challenge. The solution was to use grid-independent emissions saved out at high-resolution that would be regridded to the simulation grid at run time via HEMCO.
The grid-independent (aka offline) emissions were implemented in GEOS-Chem 12.5.0. They are available at 0.25° x 0.3125° and 0.5° x 0.625°, which correspond to the native horizontal resolution of the GEOS-FP and MERRA-2 meteorology fields used to drive GEOS-Chem. The offline emissions were generated by running the HEMCO standalone with the analogous online emissions (or HEMCO extension) turned on.
- Offline dust emissions were generated with the DustDead extension
- Offline biogenic VOC emissions were generated with the MEGAN extension
- Offline sea salt emissions were generated with SeaSalt extension
- Offline soil NOx emissions were generated with the SoilNOx extension
By default, these offline emissions are turned on. To use the online emissions instead, set the offline emissions (OFFLINE_DUST, OFFLINE_BIOGENICVOC, OFFLINE_SEASALT, and/or OFFLINE_SOILNOX) to false at the top of HEMCO_Config.rc and set the corresponding HEMCO extension (DustDead, MEGAN, SeaSalt, and/or SoilNOx) to on.
Download
The grid-independent emissions are stored on at the WashU data portal and may be accessed at the following address:
http://geoschemdata.wustl.edu
A copy of the grid-independent emissions may be found on the Harvard and Dalhousie data archives, but they are not guaranteed to be up-to-date or contain all years available.
Dust emissions
Developers: David Ridley (CARB, formerly MIT), Jun Meng (Dalhousie)
README: http://geoschemdata.wustl.edu/ExtData/HEMCO/OFFLINE_DUST/v2021-08/README
Please see this post on the Mineral Dust Aerosols wiki page for a details about the offline dust emissions.
Lightning NOx emissions
Developer: Lee Murray (Rochester)
README: http://geoschemdata.wustl.edu/ExtData/HEMCO/OFFLINE_LIGHTNING/v2020-03/GEOSFP/README
Biogenic VOC emissions
Developer: Jintai Lin (PKU) and Hongjian Weng (PKU)
README: http://geoschemdata.wustl.edu/ExtData/HEMCO/OFFLINE_BIOVOC/v2021-12/README.txt
Grid-independent offline biogenic VOC emissions are now available for GEOS-Chem at native MERRA-2 (0.5° x 0.625°) and GEOS-FP (0.25° x 0.3125°) meteorology field resolution. The emissions used in GEOS-Chem 12.5.0 and later were generated with GEOS-Chem 12.3.0 using the Yuan-processed MODIS XLAI.
Fixes for biogenic SOAP, SOAS, and CO emissions
This fix was included in GEOS-Chem 12.5.0, which was released on 09 Sep 2019.
The 1-month benchmark for GEOS-Chem 12.5.0 revealed some issues with the SOAP, SOAS, and CO emissions in the updated offline biogenic VOC emissions (in OFFLINE_BIOVOC/v2019-08/. To resolve the issues, SOAP and SOAS emissions from those files are ignored, and we instead compute those emissions directly from isoprene and monoterpene emissions.
0 BIOGENIC_ISOP $ROOT/OFFLINE_BIOVOC/v2019-08/{NATIVE_RES}/$YYYY/$MM/biovoc_{LATRES}x{LONRES}.$YYYY$MM$DD.nc ISOP_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s ISOP - 4 2
0 BIOGENIC_ISOP_SOAP - - - - - - SOAP 610 4 2
0 BIOGENIC_ISOP_SOAS - - - - - - SOAS 610 4 2
0 BIOGENIC_LIMO $ROOT/OFFLINE_BIOVOC/v2019-08/{NATIVE_RES}/$YYYY/$MM/biovoc_{LATRES}x{LONRES}.$YYYY$MM$DD.nc LIMO_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s LIMO - 4 2
0 BIOGENIC_LIMO_SOAP - - - - - - SOAP 611 4 2
0 BIOGENIC_LIMO_SOAS - - - - - - SOAS 611 4 2
0 BIOGENIC_MTPA $ROOT/OFFLINE_BIOVOC/v2019-08/{NATIVE_RES}/$YYYY/$MM/biovoc_{LATRES}x{LONRES}.$YYYY$MM$DD.nc MTPA_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s MTPA - 4 2
0 BIOGENIC_MTPA_SOAP - - - - - - SOAP 611 4 2
0 BIOGENIC_MTPA_SOAS - - - - - - SOAS 611 4 2
0 BIOGENIC_MTPO $ROOT/OFFLINE_BIOVOC/v2019-08/{NATIVE_RES}/$YYYY/$MM/biovoc_{LATRES}x{LONRES}.$YYYY$MM$DD.nc MTPO_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s MTPO - 4 2
0 BIOGENIC_MTPO_SOAP - - - - - - SOAP 611 4 2
0 BIOGENIC_MTPO_SOAS - - - - - - SOAS 611 4 2
0 BIOGENIC_SESQ $ROOT/OFFLINE_BIOVOC/v2019-08/{NATIVE_RES}/$YYYY/$MM/biovoc_{LATRES}x{LONRES}.$YYYY$MM$DD.nc SESQ_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s SESQ - 4 2
0 BIOGENIC_SESQ_SOAP - - - - - - SOAP 612 4 2
0 BIOGENIC_SESQ_SOAS - - - - - - SOAS 612 4 2
#==============================================================================
# --- Offline biogenic VOC scale factors ---
#
# Isoprene : 1.5% mass yield SOAP, 1.5% mass yield SOAS
# Monoterpenes : 5.0% mass yield SOAP, 5.0% mass yield SOAS
# Other terpenes: 5.0% mass yield SOAP, 5.0% mass yield SOAS
# --> Need to multiply by 1.133 to convert from carbon basis to mass basis
#==============================================================================
610 ISOPtoSOA 0.0170 - - - xy 1 1
611 MONOtoSOA 0.0567 - - - xy 1 1
612 OTHRtoSOA 0.0567 - - - xy 1 1
In addition, the offline biogenic CO emissions are not used to avoid double counting.
Apply temporary scaling to biogenic VOC emissions in 12.4.0
The offline biogenic VOC emissions implemented in GEOS-Chem 12.4.0 and found in HEMCO/OFFLINE_BIOVOC/v2019-01 were generated using GEOS-Chem v11-02. The following updates and fixes had been applied to MEGAN since v11-02:
- Update to a new plant functional type (PFT) file created from higher resolution data (added in 12.3.0)
- HEMCO bug fix to prevent excessive attempts to read the HEMCO restart file when using GEOS-Chem "Classic" (added in 12.1.0)
Jintai Lin's group is going to regenerate the offline biogenic VOC emissions with the latest version of the model, but as a temporary fix we are going to scale the annual biogenic VOC emission totals to those in 12.3.0. The scale factors were generated by running the HEMCO standalone using online MEGAN emissions and offline biogenic VOC emissions for one year (2016).
geosfp_4x5_MEGAN geosfp_2x25_MEGAN geosfp_4x5_OfflineBioVOC Scale Factors ACET 25.05267 Tg 24.37869 Tg 26.95496 Tg 0.9294271416 ALD2 9.882695 Tg 9.772552 Tg 8.402392 Tg 1.176176379 C2H4 21.87993 Tg 21.54709 Tg 16.22218 Tg 1.348766171 EOH 9.450429 Tg 9.345103 Tg 8.034874 Tg 1.176176378 ISOP 355.8949 Tg 364.0299 Tg 233.8795 Tg 1.521701941 PRPE 19.95450 Tg 19.46565 Tg 18.49293 Tg 1.079034029 SOAP 0.484302 Tg 0.495372 Tg 0.067689 Tg 7.154810974 SOAS 0.484302 Tg 0.495372 Tg 0.067689 Tg 7.154810974
The following changes need to be included in HEMCO_Config.rc if you're using this version of the offline biogenic VOC emissions.
#============================================================================== # --- Offline biogenic VOC emissions --- #============================================================================== 0 BIOGENIC_ACET $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc ACET_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s ACET 610 4 2 0 BIOGENIC_ALD2 $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc ALD2_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s ALD2 611 4 2 0 BIOGENIC_C2H4 $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc C2H4_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s C2H4 612 4 2 0 BIOGENIC_EOH $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc EOH_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s EOH 613 4 2 0 BIOGENIC_ISOP $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc ISOP_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s ISOP 614 4 2 0 BIOGENIC_PRPE $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc PRPE_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s PRPE 615 4 2 0 BIOGENIC_SOAP $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc SOAP_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s SOAP 616 4 2 0 BIOGENIC_SOAS $ROOT/OFFLINE_BIOVOC/v2019-01/0.25x0.3125/$YYYY/$MM/biovoc_025.$YYYY$MM$DD.nc SOAS_MEGAN 1980-2017/1-12/1-31/0-23 C xy kgC/m2/s SOAS 616 4 2 ... 610 ACET_SF 0.929 - - - xy 1 1 611 ALD2_SF 1.176 - - - xy 1 1 612 C2H4_SF 1.349 - - - xy 1 1 613 EOH_SF 1.176 - - - xy 1 1 614 ISOP_SF 1.522 - - - xy 1 1 615 PRPE_SF 1.079 - - - xy 1 1 616 SOA_SF 7.155 - - - xy 1 1
--Melissa Sulprizio (talk) 16:07, 18 June 2019 (UTC)
Sea salt emissions
Developer: Jintai Lin (PKU) and Hongjian Weng (PKU)
README: http://geoschemdata.wustl.edu/ExtData/HEMCO/OFFLINE_SEASALT/v2019-01/README
Soil NOx emissions
Developer: Jintai Lin (PKU) and Hongjian Weng (PKU)
README: http://geoschemdata.wustl.edu/ExtData/HEMCO/OFFLINE_SOILNOX/v2021-12/README.txt