Difference between "species" and "surrogate" terms in CMAQv53 context?



I am confused about the definition of surrogate in CMAQv53 context. Does surrogate here mean pollutant_name before chemical speciation or something else? because I am getting an error in CMAQv53 where both species and surrogate terms are used together: “for optimal prediction, species with the missing surrogates should have a surrogate found in at least one source”.



Hi Ehsan,

Yes, surrogate here means the name of the pollutant as it is represented on an Emissions Stream. For example, from a typical gridded emission file created by SMOKE using AE6 nomenclature, the elemental carbon surrogate is named “PEC”. Meanwhile, in CMAQ, this pollutant is transported and deposited under the species name “AEC”.

The error you are getting is telling you that you are trying to map a CMAQ species to a variable that is not present on any of the emission streams you have identified for input. There should be a verbose output just before this error that lists the surrogate(s) that could not be found. Sorry for the confusion here.

Best regards,