MERIS Level 1 Radiometric Processor - MERIS Smile Correction Algorithm Specification |

### Auxiliary Data Files

The MERIS Smile Correction uses three different sets of auxiliary data files for processing. All of them are flat text files:

1. For all MERIS L1b products: band_info.txt
2. For MERIS L1b full resolution products: central_wavelen_fr.txt, sun_spectral_flux_fr.txt
3. For MERIS L1b reduced resolution products:central_wavelen_rr.txt, sun_spectral_flux_rr.txt

#### band_info.txt

This file contains a header line followed by 15 lines associated with each MERIS band. The header line explains the parameters contained in this file. The columns are

1 | `band` | the one-based band index (ignored)
2 | `switch_land` | whether or not to perform reflectance correction over land
3 | `lower_land` | lower, one-based band index to be used for correction over land
4 | `upper_land` | upper, one-based band index to be used for correction over land
5 | `switch_water` | whether or not to perform reflectance correction over water
6 | `lower_water` | lower, one-based band index to be used for correction over water
7 | `upper_water` | upper, one-based band index to be used for correction over water
8 | `lam_theo` | theoretical band wavelength in nm
9 | `E0_theo` | solar spectral flux in LU for the theoretical band wavelength

The Smile Correction always ignores the header line and the first column.

#### central_wavelen_fr.txt / central_wavelen_rr.txt

This files contain a header line followed by 3700 (FR) resp. 925 (RR) lines associated with each detector containing the zero-based detector index in the first column and the central wavelengths (in nm) for each MERIS band.
The Smile Correction always ignores the header line and the first column.

#### sun_spectral_flux_fr.txt / sun_spectral_flux_rr.txt

This files contain a header line followed by 3700 (FR) resp. 925 (RR) lines associated with each detector containing the zero-based detector index in the first column and the solar spectral fluxes (in LU) for each wavelength for each MERIS band.
The Smile Correction always ignores the header line and the first column.