Program and Agenda

Abstract

EVALUATION OF THE UTILITY OF XANTHOPHYLL CYCLE PIGMENT DYNAMICS FOR ASSESSING UPPER OCEAN MIXING PROCESSES AT STATION ALOHA

Upper ocean mixing processes are important because they provide a link between the atmosphere and the deep ocean, and are responsible for the air-sea exchange of freshwater, heat, momentum and gases. The measurement and modeling of boundary layer turbulence in the ocean is challenging because it varies by several orders of magnitude. We had the opportunity to evaluate the utility of xanthophyll cycle pigment (XCP = diatoxanthin + diadinoxanthin) dynamics for assessing upper ocean mixing rates at Station ALOHA during August-September 2012 (HOE-DYLAN). A time-series of phytoplankton pigments was collected from the sea-surface in order to calculate rates of photoadaptation (dP/dt = time-dependent changes in XCP/CHLA) during the daylight hours. In situ XCP/CHLA values were measured in the mixed layer using a diaphragm pumping system. Turbulent transfer velocity (TTV = dx/dt, cm/sec) was estimated as the quotient of the XCP/CHLA photoadaptation rate and the XCP/CHLA gradient (dP/dx) in the mixed layer. TTVs ranged from 0.3 to 0.5 cm/sec during HOE-DYLAN, and agreed to within a factor of ~2 of the Lagrangian float-derived estimate of vertical mixing at a comparable friction velocity.

https://sites.google.com/a/hawaii.edu/cmore-bidigare/

Authors

Bidigare, R. R., University of Hawaii, USA, bidigare@hawaii.edu

Buttler, F. R., University of Hawaii, USA, fenina@hawaii.edu

Christensen, S. J., University of Hawaii, USA, stephc@soest.hawaii.edu

Barone, B., University of Hawaii, USA, benedetto.barone@gmail.com

Wilson, S. T., University of Hawaii, USA, stwilson@hawaii.edu

Details

Oral presentation

Session #:049
Date: 2/27/2014
Time: 14:00
Location: 313 B

Presentation is given by student: No