RobertPincus
commented
3 months ago Adding here some of the off-line conversations with @dr0cloud:
The application here to be in producing band-wise top-of-atmosphere Jacobians so the TOA radiation between radiation time steps can be computed quickly.
The disadvantage to the proposed approach is that it requires a new array of size ncol*nlay*ngpt rather than accumulating broadband Jacobians on the fly. The same output could, in principle, be obtained by doing a one-layer gas optics calculation with increased surface temperature, recomputing the radiation transfer with the original optical properties and the new surface source function, and using a bespoke ty_fluxes class that computed TOA band-by-band fluxes. This is less efficient but probably not prohibitive, and @dr0cloud is going to look into it.
For review by @RobertPincus ... Please see @mathomp4 for git questions: The motivation is to add surface temperature Jacobians by band. The proposed solution was to add the Jacobians to ty_fluxes and use the same reduce infrastructure to make them available per band, per g-point, or however. It also makes the call to rte_lw() a bit cleaner since the Jacobian no longer appears as an optional item in that call. I am not wedded to this solution .... just for your review and some discussion. Thanks, Peter.