Adding passive species to GEOS-Chem
On this page we describe how to add passive species into GEOS-Chem simulations.
Passive species are often used in modeling studies to assess transport from different regions/sources, especially in model intercomparison studies. These species are usually CO-like in that they have the same emissions as CO but with no secondary sources and a fixed-lifetime (no chemistry, wet deposition, or dry deposition). Passive species are not a standard feature of GEOS-Chem, but can be added for individual projects by following a series of steps.
NOTE: For all intents and purposes, the terms "passive tracers" and "passive species" are identical. In GEOS-Chem v11-01 and higher versions, the distinction between tracers and species has been eliminated. We can now speak of everything as a "species". Those species that are moved around by the winds and convective mass fluxes—which were formerly called "tracers"—are now referred to as "advected species". For more information, please see this post on our Species indexing in GEOS-Chem wiki page.
In GEOS-Chem v11-01 and higher versions
The HEMCO emissions component v1.1.016 and higher versions now contain an extension to specify emissions of a passive species. This was first introduced into GEOS-Chem v11-01e and incorporated into the species database in v11-01j.
Prior to GEOS-Chem v11-01
Prior to GEOS-Chem v11-01, passive species had to be added manually into GEOS-Chem. The guide linked below (based on GEOS-Chem v9-01-03) details these steps. For more information, please contact Jenny Fisher (jennyf [at] uow [dot] edu [dot] au).
--Jenny Fisher, 16 May 2013