Armstrong, R. A. University of Puerto Rico, neptune@caribe.net
Detres, Y. A. University of Puerto Rico, ydetres@hotmail.com

 
ATTENUATION COEFFICIENTS OF DOWNWELLING ULTRAVIOLET AND VISIBLE IRRADIANCE IN NEAR SHORE TROPICAL WATERS
 
Underwater measurements of incident ultraviolet (UV) and visible radiation were obtained for coastal and coral reef lagoon areas in southwestern Puerto Rico. Downwelling irradiance measurements were obtained at several depths and above the water surface using an Optronic OL-754 spectroradiometer coupled to an underwater integrating sphere. Data were collected every 2 nm between 280 and 700 nm and corrected for immersion effects. Attenuation coefficients (Kd) were calculated using Kd = 1/(Z2-Z1) x ln(Ed1/Ed2) where Ed1 and Ed2 represents downwelling irradiance values at depths Z1 and Z2, respectively. The spatial and temporal variability of the attenuation coefficients was addressed in order to model UV fluxes and PAR (Photosynthetically-Active Radiation) reaching benthic communities. Comparisons were made between the OL-754 field surface measurements and a Biospherical Instruments GUV-511 radiometer at discrete bands (305, 320, 340, and 380 nm and PAR).
 
Day: Wednesday, Feb. 3
Time: 08:30 - 08:45am
Location: Sweeney Center
 
Code: CS65WE0830S