Besides empirical algorithms with the blue-green
ratio, the algorithms based on fluorescence are also important
and valid methods for retrieving chlorophyll-a concentration in
the ocean waters, especially for Case II waters and the sea with
algal blooming. This study reviews the history of initial cognitions,
investigations and detailed approaches towards chlorophyll
fluorescence, and then introduces the biological mechanism of
fluorescence remote sensing and main spectral characteristics
such as the positive correlation between fluorescence and
chlorophyll concentration, the red shift phenomena. Meanwhile,
there exist many influence factors that increase complexity of
fluorescence remote sensing, such as fluorescence quantum
yield, physiological status of various algae, substances with
related optical property in the ocean, atmospheric absorption
etc. Based on these cognitions, scientists have found two ways
to calculate the amount of fluorescence detected by ocean color
sensors: fluorescence line height and reflectance ratio. These
two ways are currently the foundation for retrieval of chlorophyll-a
concentration in the ocean. As the in-situ measurements and
synchronous satellite data are continuously being accumulated,
the fluorescence remote sensing of chlorophyll-a concentration
in Case II waters should be recognized more thoroughly and
new algorithms could be expected.