Fluorescence index Fluorescence index for measuring fluorescent dissolved organic matter (FDOM). Ratio of emission intensity at 470nm to intensity at 520nm at excitation 370nm. https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.2001.46.1.0038 Added to support Critical Zone Observatory (CZO) data use cases. ODM2 Variable Name Controlled Vocabulary ODM2 Working Group A vocabulary for describing the name of Variables.