Dear developers,

As noted in #14799, the calculation results when using the Wide Band Model depend on the PATH_LENGTH.
Appendix C in the Tech. Ref. Guide states that when the number of bands is more than one, only the Planck mean coefficient, which is independent of the PATH_LENGTH, is used in calculating the absorption coefficient. As far as I understand, the Wide Band Model implies the case of N==6.

I took a quick look at the implementation of the absorption coefficient calculation in radi.f90.

      CALL SUB_RADCAL(AMEAN,AP0,RADIANCE,TRANSMISSIVITY)
      IF (NSB==1 .AND. PATH_LENGTH > 0.0_EB) THEN
         RADCAL_SPECIES2KAPPA(NS,J,K,1) = MIN(AMEAN,AP0)
      ELSE
         RADCAL_SPECIES2KAPPA(NS,J,K,IBND) = AMEAN/BBF
      ENDIF

As far as I understand, AMEAN is EFFECTIVE_ABSORPTION (or path mean), not PLANCK_MEAN_ABSORPTION.
This doesn't seem to match what is written in the manual for the NSB > 1 case.

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