GEOS-Chem Newsletter Spring 2012

GEOS-Chem v9-01-03

Since the last GEOS-Chem Steering Committee telecon (15 Feb 2012), the following 1-month benchmarks have been performed for GEOS-Chem v9-01-03. For the complete table of v9-01-03 1-month benchmarks, click HERE.

1. v9-01-03f:
   • PARANOX ship plume emissions (G.C.M. Vinken, Eindhoven)
   • Bug fixes for David Streets emissions for nested model (J. Fisher, Harvard)
2. v9-01-03g:
   • Several minor bug fixes not affecting the full-chemistry simulation (GCST)
   • Addition of lightning scale factors for MERRA 2 x 2.5 met (GCST)
   • Initial source code modifications for GEOS-5.7.2 (GCST)
   • Support added for netCDF file I/O (GCST)
3. v9-01-03h:
   • Hg(II) gas-aerosol partitioning (H. Amos, Harvard)
   • Nested grid CO2 simulation (Y.X. Wang, Tsinghua)
   • Historical emission inventories of SO2, NOx, BC, POA (E. Leibensperger, MIT)
   • CH4 simulation updates (K. Wecht, Harvard)
   • Removed support for GEOS-3 (GCST)
   • Bug fix in David Streets emissions for offline simulation (F. Paulot, Harvard)
4. v9-01-03i:
   • Updates to facilitate inclusion of Grid-Independent model code (GCST)
   • Replace RETRO C2H6 with emissions from offline C2H6 simulation (GCST)
5. v9-01-03j:
   • Updated LAI code, to facilitate Grid-Independent model (GCST)
   • Preliminary interface to connect G-C to an external GCM (GCST)
6. v9-01-03k:
   • Replace existing regridding routines with MAP_A2A package (M. Cooper, GCST)
7. v9-01-03l:
   • Daily and hourly GFED3 biomass emissions (P. Kasibhatla, Duke)

Of these, v9-01-03l is still pending approval, and the rest have already been approved.

The following 1-month benchmarks are currently planned before the final 1-year benchmarking and public release of v9-01-03:

1. v9-01-03m:
   • Tropospheric bromine simulation (J. Parella, Harvard)
   • Bug fix in routine ARSL1K (GCST)
2. v9-01-03n:
   • Stratospheric monthly climatological P and K (Lee Murray, Harvard)

We will perform a 1-year benchmark for v9-01-03m in addition to the customary 1-month benchmarks. The bromine simulation needs to be in place before the Stratopsheric P/K update can be validated into the standard code.

One of our primary focuses in this past quarter was to ingest the grid-Independent modifications into the standard GEOS-Chem repository. This was necessary to ensure that the Grid-Independent development code would not lag behind the standard GEOS-Chem. Frequent synchronization of these two streams of model development will be necessary going forward.

Our goal has been to introduce the Grid-Independent functionality without destroying any of the existing GEOS-Chem functionality. We have done this in a manner akin to building a new highway bridge next to the old bridge. For a time, both bridges are situated side-by-side, but eventually the old bridge gets taken down and replaced by the new.

We have added new sections of Grid-Independent code into GEOS-Chem routines while keeping the existing code as well. We used a C-preprocessor switch named DEVEL to block off the new sections of code from the existing sections of code. For the most part, these modifications occur at the entry points of subroutines, so that the arguments that need to be passed into the subroutine may be passed by Fortran derived type objects rather than via arrays or by USE statements. (This will make it easier to interface with the ESMF framework). Once the new sections of code have been fully tested and validated with benchmark simulations, they will replace the older sections of GEOS-Chem code. We plan on updating many sections of code prior to the public release of v9-01-03, in order to avoid the confusion.

We have also started to add modifications necessary for driving GEOS-Chem with the GEOS-5.7.2 met data to the standard code.