Assessing natural fluorescence dynamics using radiometry on long-term ocean moorings

Samuel Laney, Woods Hole Oceanographic Institution, slaney@whoi.edu (Presenter)

A hyperspectral radiometry system was deployed on the surface buoy of a long-term open-ocean mooring at the Hawaiian Ocean Time-series (HOT) site in June 2011. This system measures incident solar irradiance at 190 wavelengths between 320 to 950 nm, as well as water-leaving radiance at four orthogonal directions relative to the surface buoy’s orientation, each at 45 degrees from nadir. The primary goal of this project is to measure the time-dependent behavior of natural fluorescence at this site, with temporal resolution adequate for testing and developing ecophysiological models for natural fluorescence dynamics on sub-diel scales. This radiometry system records incident and water-leaving spectra, as well as buoy orientation and the current ocean chlorophyll concentration as measured by an in situ fluorometer mounted to the buoy’s hull, every ten minutes during the daytime. A subset of these data is transmitted to shore daily at solar noon over an Iridium link, providing daily, real-time observations of the observations collected at that time. By locating this system on a mooring near the HOT site, optical and biological properties measured by the monthly HOT survey teams can be used to guide the interpretation of these radiometric and fluorescence measurements. Although natural fluorescence is the main focus of this study, the multiple downlooking radiometers are also generating a potentially useful data set for assessing the bidirectional radiance distribution function and its variability over daily and seasonal scales in the open ocean. Future directions for 2012 involve the addition of long-term, mooring-compatible fast repetition rate fluorometers to this system, so that physiological controls on the water-leaving fluorescence can be assessed in the context of observed variability in natural fluorescence.

Presentation Type:  Poster

Session:  Coupled Processes at Land-Atmosphere-Ocean Interfaces   (Mon 4:00 PM)

Associated Project(s): 

• Laney, Samuel: Deciphering the Natural Fluorescence Dynamics of Phytoplankton ...details

Poster Location ID: 48