Basic Python wrapper for functionality of the SPCTRAL2 atmospheric radiative transfer C code.
- Current version is a naive approach, requiring compiling the C code for every run.
- Future version will include a Cython-based interface (in-progress)
See also SolarUtils, which provides a SPCTRAL2 wrapper
using ctypes, and adds the ability to optionally specify surface albedos at 6 wavelengths,
which SPCTRAL2 uses to create the interpolated albedo spectrum it uses internally
(pyspctral2 does not currently consider support this input; the default settings are used).
The Bird Simple Spectral Model v2 (SPCTRAL2) is a simple atmospheric radiative transfer model that predicts spectral irradiance at the surface.
- 122 bands, in region 0.3–4.0 μm, with higher spectral resolution in UV and Vis
- Predicts diffuse light and direct solar beam
- Processes modeled using semi-empirical exponential extinction:
- Ozone absorption
- Water vapor absorption and scattering
- Aerosol absorption
- Refraction
Default spectra (taken from the Excel version, all default settings):
These inputs control the solution that SPCTRAL2 returns.
Essential
- Location (lat, lon)
- Date, time, UTC offset
- total column ozone
- If not known, SPCTRAL2 will internally estimate total column ozone using a parameterization by location of date/time.
- total column precipitable water
- aerosol optical depth at 500 nm
- Angle (tilt and aspect) of hypothetical flat collector
- ...