Allow array values for solar irradiance factor adjes

[brian-rose]

RRTMG_SW accepts a scalar input adjes which modifies the top-of-atmosphere irradiance (scon * adjes). Normally this parameter is used to represent Sun-Earth distance effects due to the elliptical orbit and time of year.

We are working to support alternative ways of specifying the time-averaged solar zenith angle in climlab to address scattering biases associated with low sun angle in models that use daily average insolation (e.g. zonal average models, single column models).

Modifying the time-averaged solar zenith angle then requires adjusting the irradiance to preserve time-averaged insolation, which is always scon * adjes * coszen.

The problem is that the modified value of adjes is latitude-dependent. So for models that use daily average insolation on a latitude grid, we need to support providing different adjes values at each grid point.

climlab/climlab#235 and climlab/climlab#208 are waiting on this upgrade to climlab-rrtmg.