NSTR

Isaac's 2-stream (0) or Number of DISORT streams (2-32)

Attributes

integer | discrete | static | unit-less | advanced

Description

The variable NSTR allows selecting method used in the calculation of multiple scattering. The following options are available:

  • If NSTR=0, MODTRAN will use the faster but less accurate Isaac's two-stream algorithm (Isaacs et al., 1998).
  • If NSTR takes one value between 2 and 32, MODTRAN activates the DISORT discrete ordinate multiple scattering algorithm (Stammes et al., 1988) with the number of streams selected in NSTR. Using high values generally improves accuracy but slows computation. NSTR=8 (default value) consider enough, although more streams may be desirable if modeling highly forward peaked scatters.
  • If NSTR=-1 is chosen, DISORT calculations are performed at selected spectral points in the atmospheric window regions. These handfuls of DISORT radiances are then used to scale Isaac's values for the entire wavelength region.

References