Radiative-transfer layer options

Select the within-layer approximation with rte_option.

Table 1 Radiative-transfer layer options

Option	Within-layer model	Step
constant	Endpoint-average propagation matrix and source	Ordinary matrix exponential with a layer-average source.
lintau	Constant propagation matrix and linear source	Uses the linear-source operator \(\Lambda\) derived in Radiative Transfer.
linprop	Linear propagation and linear source	Uses the exact scalar linear-propagation source integral. Polarized transfer uses endpoint-average transmission with a commutator-free augmented-source correction.
magop	Linear propagation matrix and layer-average source	Uses the second-order Magnus exponent and the ordinary source step.
magop_linsrc	Linear propagation matrix and linear source	Adds Magnus-ordered transmission to the augmented linear-source operator by retaining the first propagation-matrix commutator.

All five options propagate analytical derivatives of their transmittance and, where applicable, source operators. magop and magop_linsrc are most useful when the polarized propagation matrices at the layer endpoints do not commute. For scalar transfer, linprop evaluates the linear-propagation source integral exactly. For polarized transfer, linprop retains the ordinary endpoint-average transmission, whereas magop_linsrc also includes the Magnus ordering correction.

See Radiative Transfer for the equations behind these options.