The MODIS instruments on Terra and Aqua were designed to allow the measurement of chlorophyll fluorescence
effects over ocean. The retrieval algorithm is based on the difference between the water-leaving radiances at
667nm and 678nm. The water-leaving radiances at these wavelengths are usually very low relative to the topof-
atmosphere radiances. The high radiometric accuracy needed to retrieve the small fluorescence signal lead to
a dual gain design for the 667 and 678nm bands. This paper discusses the benefits obtained from this design
choice and provides justification for the use of only one set of gains for global processing of ocean color products.
Noise characteristics of the two bands and their related products are compared to other products of bands from
412nm to 2130nm. The impact of polarization on the two bands is discussed. In addition, the impact of stray
light on the two bands is compared to other MODIS bands.