3.3 Instrument Characteristics and Performance

3.3.1 Instrument characteristic

The MS Excel document “MERIS_Wavelenghts_and_Irradiances_2005.xls” can be found at address http://earth.esa.int/pcs/envisat/meris/documentation/

This document gives :

• the central wavelengths of each FR pixel for each band (pixel 1 is East, pixel 3700 is West),
• corresponding in-band irradiances (derived using above wavelengths, computed instrument response functions and reference irradiances from sheet 4, scaled to Sun-Earth distance for MERIS reference day of year 95),
• FWHM (Full Width at Half Modulation) of the instrument response functions for each band of each camera (each camera has 740 FR pixels – there is no FWHM variation for a given band within a given camera FOV -; camera 1 is east, camera 5 is west),
• sheet 4 contains the reference Irradiance at 1 AU adopted for ENVISAT (Thuillier, G., M. Hersé, P. C. Simon, D. Labs, H. Mandel, D. Gillotay, and T. Foujols, The solar spectral irradiance from 200 to 2400 nm as measured by the SOLSPEC spectrometer from the ATLAS 1-2-3 and EURECA missions, Solar Phys., submitted, 2002.),
• sheets 5 to 9 hold the instrument response functions for cameras 1 to 5 (hence 5 sheets), for each band, computed at centre of FOV (between pixels 370 & 371). Each function is scaled to max=1.