WHOI Hawaii Ocean Timeseries Station (WHOTS) : WHOTS-4 2007 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. .0′W in 4756 m of water. This was followed by meteorological intercomparisons and CTDs at the WHOTS-4 and WHOTS-3 sites. The WHOTS-3 mooring was recovered on June 28th followed by CTD operations at the HOT site and shipboard meteorological observations at several sites to the south of the mooring site. This report describes these cruise operations, as well as some of the in-port operations and pre-cruise buoy preparations.iv

WHOI Hawaii Ocean Timeseries Station (WHOTS) : WHOTS-6 2009 mooring turnaround cruise report

“…2-3). Night-time AT disagreement had been seen before on the pier at the UH Marine Center, and examination of the WHOTS-4 cruise report (Whelan et al, 2008) showed that night-time AT differences approaching 1.0C were characteristic of two modules that were later shown to be working properly (these modules agreed to within 0.1C during the day). The WHOTS-4 nighttime discrepancy was attributed to spatial gradients.…”

“…The "southeast site" was occupied by WHOTS-4 and was the target site for WHOTS-6. Bathymetry data from the archives of the Hawaii Mapping Research Group (HMRG) as well as multi-beam surveys during previous WHOTS cruises (e.g., Whelan et al, 2007;2008) indicated depths of 4700 ± 20 m, near the eastern site and 4760 m 20 m near the southeast site. The nominal WHOTS mooring design is for a depth of 4700 m 100 m, so no adjustments in mooring length are necessary for either site.…”

“…The upper 155 m of the mooring line is outfitted with oceanographic sensors for the measurement of temperature, conductivity and velocity. Starting with the WHOTS-4 deployment (Whelan et al, 2008), a pCO2 system for investigation of the air-sea exchange of CO2 at the ocean surface was mounted in the buoy well in cooperation with Chris Sabine at the Pacific Marine Environmental Laboratory (PMEL).…”