The response functions are from CHRIS Data Format document.

CHRIS has different operation modes, which are indicated by the letter after the last underscore of the names of the filterfunctions:
*_aXX: Mode 1
*_wXX: Mode 2 - water bands
*_lXX: Mode 3 - land channels
*_lXXa: Mode 3a - land channels
*_cXX: Mode 4 - chlorophyll band set
*_hXX: Mode 5 - land channels

[XX is the number of channel]
