The A/BEMISSIONS files contain the emissions in molecules/cm2/s on the model’s grid at an hourly resolution. Among the species in A/BEMISSIONS.nc, only those which are listed in the ANTHROPIC/BIOGENIC files of the chemical scheme are used. The AEMISSIONS are kept constant during the one-hour time steps in CHIMERE (historically used for anthropogenic emissions); the BEMISSIONS are linearly interpolated within the 1-hour time steps (historically used for biogenic emissions). AEMISSIONS are required for a simulation, BEMISSIONS can be ignored with the switch optemisb.
See also the fluxes plugin for CHIMERE for documentation on these files and the information to provide to the CIF to generate them.
The format of the A/BEMISSIONS.nc is as follows, with PP, NZONAL and NMERID given the relevant values, NVERTI being the number of levels on which emissions are to be found (NVERTI can be smaller than the number of levels of the simulation grid: this saves a lot of space in the input files since it is not usual to have emissions very high in altitude) and NS the number of ANTHROPIC/BIOGENIC species:
dimensions: Time = PP+1 ; south_north = NMERID ; west_east = NZONAL ; bottom_top = NVERTI ; SpStrLen = 23 ; DateStrLen = 19 ; Species = NS ; variables: char species(Species, SpStrLen) ; float lon(south_north, west_east) ; lon:units = "degrees_east" ; lon:long_name = "Longitude" ; float lat(south_north, west_east) ; lat:units = "degrees_north" ; lat:long_name = "Latitude" ; char Times(Time, DateStrLen) ; double S1(Time, bottom_top, south_north, west_east) ; S1:units = "molecule/cm2/s" ; S1:long_name = "S1 emissions" ; double S2(Time, bottom_top, south_north, west_east) ; S2:units = "molecule/cm2/s" ; S2:long_name = "S2 emissions" ; . . . double SNS(Time, bottom_top, south_north, west_east) ; SNS:units = "molecule/cm2/s" ; SNS:long_name = "SNS emissions" ;
- Important points:
the actual length of record is PP+1 since one hour more than the covered period is required for time interpolation within the last simulation hour.
the dates are written in a fixed format on 19 characters (DateStrLen): YYYY-MM-DD_HH:mm:ss
a species can be both in ANTRHOPIC and in BIOGENIC: its emissions are added in CHIMERE
the species names can be as long as SpStrLen = 23 characters
the emissions must be written as
floatto ensure enough precision for the adjoint.