WHOI Hawaii Ocean Timeseries Station (WHOTS) : WHOTS-5 2008 mooring turnaround cruise report

Abstract

The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries (HOT) Site (WHOTS), 100 km north of Oahu, Hawaii, is intended to provide long-term, high-quality air-sea fluxes as a part of the NOAA Climate Observation Program. The WHOTS mooring also serves as a coordinated part of the HOT program, contributing to the goals of observing heat, fresh water and chemical fluxes at a site representative of the oligotrophic North Pacific Ocean. The approach is to maintain a surface mooring outfitted for meteorological and oceanographic measurements at a site near 22.75°N, 158°W by successive mooring turnarounds. These observations will be used to investigate air–sea interaction processes related to climate variability. The first four WHOTS moorings (WHOTS-1 through 4) were deployed in August 2004, July 2005, June 2006, and June 2007, respectively. This report documents recovery of the WHOTS-4 mooring and deployment of the fifth mooring (WHOTS-5). Both moorings used Surlyn foam buoys as the surface element and were outfitted with two Air–Sea Interaction Meteorology (ASIMET) systems. Each ASIMET system measures, records, and transmits via Argos satellite the surface meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum. The upper 155 m of the moorings were outfitted with oceanographic sensors for the measurement of temperature, conductivity and velocity in a cooperative effort with R. Lukas of the University of Hawaii. A pCO2 system was installed on the WHOTS-5 buoy in a cooperative effort with Chris Sabine at the Pacific Marine Environmental Laboratory. The WHOTS mooring turnaround was done on the University of Hawaii research vessel Kilo Moana, Cruise KM-08-08, by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place between 3 and 11 June 2008. Operations began with deployment of the WHOTS-5 mooring on 5 June at approximately 22°46.1'N, 157°54.1'W in 4702 m of water. This was followed by meteorological intercomparisons and CTDs at the WHOTS-4 site. A period of calmer weather was taken advantage of to recover WHOTS-4 on 6 June 2008. The Kilo Moana then returned to the WHOTS-5 mooring for CTD operations and meteorological intercomparisons. This report describes these cruise operations, as well as some of the in-port operations and pre-cruise buoy preparations.