ICID 25 => DARK_GLOBAL_OZONEHOLE_FM

Illumination:

  • Dark (background) measurements corresponding to Earth radiance measurements of ICID 7.

Purpose:

  • Global dark (background) measurements to verify whether or not ICID 6 (DARK_GLOBAL_OZONEHOLE) measurements are affected by Earth light.

Location:

  • Eclipse side of the orbit (2 blocks per orbit).

Usage:

  • From launch onwards, at a weekly frequency.

Description:

Dark (background) measurements with the exact same instrument settings as the EARTH_GLOBAL_OZONEHOLE light measurement of ICID 7 and the DARK_EARTH_GLOBAL_OZONEHOLE measurement of ICID 6. The dark (background) measurements are performed at the eclipse side of the orbit in 2 blocks: just after the satellite has entered the eclipse side and just before the satellite will leave the eclipse side of the orbit. These dark measurements use the folding mirror to block the Earth light. The dark (background) measurements of ICID 25 (with use of the folding mirror) are used to verify whether or not the dark (background) measurements of ICID 6 (without use of the folding mirror) are affected by Earth light entering the instrument.