Hello to all,Concerning the sulphate aerosol size bins given by PURSUL01 to PURSUL30, I read somewhere that the corresponding sizes ranged from 0.3 nm to 1.6 µm.I take it these would be radii, since assuming diameter would give really small size bins (practically molecule-sized for the first one).Can anyone confirm that we are indeed talking of radii and not diameters?Thank you very much,Thibaut.
Sulphate PURSUL size bins
- Thread starter thibaut_lurton@cnrs-orleans_fr
- Start date
These are bins for the CARMA sulfate model. There may be approximate dry radius for each bin listed in the long_name metadata for each variable. However, these bins are based on mass of sulfate, so dry radius will vary with temperature (density), and the wet radius will also vary with water vapor content. You can output the actual dry and wet radii of each bin as a separate variable (check the MASTER FIELD LIST in your atm.log.* output in your run directory for available history variable names).In cam/src/physics/carma/models/sulfate/carma_model_mod.F90, the number of bins is set at 30, the dry radius of the smallest bin is set to 0.343 nm (2 H2SO4 molecules), and subsequent bins increase the volume by a factor of 2.4: integer, public, parameter :: NBIN = 30 !! Number of particle bins! Set radius of smallest bin such that mass is that of 2 molecules of H2SO4: real(kind=f), parameter :: rmin = 3.43230298e-8_f ! minimum radius (cm) real(kind=f), parameter :: vmrat = 2.4_f ! volume ratioThese parameters can be modified by the user.
Thank you Mike for this very detailled and helpful answer.Two questions I ask myself:1) Instead of a fixed log-progression over the sizes (induced by the geometrical progression of volumes), would it be possible to wholly prescribe the size bins "by hand" to some radius values I wish?2) Do these size bins relate only to an output process, or do they also affect the inner microphysics scheme?Thank you very much.Thibaut.
Hello,I could not find the wet radius output variables in the master field list. Could you please indicate what name they should have?Thank you very much.Thibaut.
My apologies. The wet radius is not output. I calculate it in post-processing, using these NCL scripts:https://svn.code.sf.net/p/codescripts/code/trunk/ncl/allSaveSize.nclhttps://svn.code.sf.net/p/codescripts/code/trunk/ncl/common2.nclThe second file includes the procedure calcPurSulRad, which is called in the first file.