Experience With Moored Observations in the Western Gulf of Maine From 2006 to 2012

The University of New Hampshire is studying CO2 gas exchange, ocean acidification, air-sea dynamics, and associated biological processes in the western Gulf of Maine. Two buoys provide data supporting these studies. The UNH CO2 buoy has been deployed jointly with the National Oceanic and Atmospheric Administration (NOAA)’s Pacific Marine Environmental Laboratory northeast of the Isles of Shoals since 2006. The Jeffreys Ledge Moored Observatory is a development mooring testing new techniques and is deployed east of Gloucester, MA. This mooring is testing the direct covariance measurement of wind stress using a 3-D sonic anemometer with a motion package to remove buoy motion effects. A fast-rate atmospheric CO2 sensor is mounted by the anemometer to evaluate its potential for direct covariance gas flux measurements. Both buoys have additional meteorological and oceanographic sensors to provide supporting measurements. Six years of CO2 buoy data have helped quantify the seasonal air-sea flux cycle of CO2 in the Western Gulf of Maine. The buoy is now a node in near-term ocean carbon cycle process control experiments and longer-term ocean acidification monitoring. The Jeffreys Ledge buoy momentum flux measurements using wind and motion measurements indicate reasonable first-order buoy motion corrections can be made. Also, buoy-induced flow disturbance requires postmeasurement corrections. Rapid buoy azimuthal rotations were corrected with the addition of a steering vane. A vertical array of oxygen sensors captures phytoplankton bloom signatures and provides net community production estimates that augment in-water SAMI-CO2 measurements and add to a robust system to support process studies and improved biophysical modeling within this region.