Description: Author Posting. © Sears Foundation for Marine Research, 2006. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 64 (2006): 745-758, doi:10.1357/002224006779367285.

Description: Mixed layer depth (MLD) is an important oceanographic parameter. However, the lack of direct observations of MLD hampers both specification and investigation of its spatial and temporal variability. An important alternative to direct observation would be the ability to estimate MLD from surface parameters easily available from satellites. In this study, we demonstrate estimation of MLD using Artificial Neural Network methods and surface meteorology from a surface mooring in the Arabian Sea. The estimated MLD had a root mean square error of 7.36 m and a coefficient of determination (R2) of 0.94. About 67% (91%) of the estimates lie within ± 5 m (± 10 m) of the MLD determined from temperature sensors on the mooring.

Description: Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): C06014, doi:10.1029/2006JC003947.

Description: In aerial surveys conducted during the Tropical Ocean–Global Atmosphere Coupled Ocean-Atmosphere Response Experiment and the low-wind component of the Coupled Boundary Layer Air-Sea Transfer (CBLAST-Low) oceanographic field programs, sea surface temperature (SST) variability at relatively short spatial scales (O(50 m) to O(1 km)) was observed to increase with decreasing wind speed. A unique set of coincident surface and subsurface oceanic temperature measurements from CBLAST-Low is used to investigate the subsurface expression of this spatially organized SST variability, and the SST variability is linked to internal waves. The data are used to test two previously hypothesized mechanisms for SST signatures of oceanic internal waves: a modulation of the cool-skin effect and a modulation of vertical mixing within the diurnal warm layer. Under conditions of weak winds and strong insolation (which favor formation of a diurnal warm layer), the data reveal a link between the spatially periodic SST fluctuations and subsurface temperature and velocity fluctuations associated with oceanic internal waves, suggesting that some mechanism involving the diurnal warm layer is responsible for the observed signal. Internal-wave signals in skin temperature very closely resemble temperature signals measured at a depth of about 20 cm, indicating that the observed internal-wave SST signal is not a result of modulation of the cool-skin effect. Numerical experiments using a one-dimensional upper ocean model support the notion that internal-wave heaving of the warm-layer base can produce alternating bands of relatively warm and cool SST through the combined effects of surface heating and modulation of wind-driven vertical shear.

Description: We gratefully acknowledge funding for this research from the Office of Naval Research through the CBLAST Departmental Research Initiative (grants N00014-01-1-0029, N00014-05-10090, N00014-01-1-0081, N00014-04-1-0110, N00014-05-1-0036, N00014-01-1-0080) and the Secretary of the Navy/Chief of Naval Operations Chair (grant N00014-99-1-0090).

Description: The Ocean Reference Station at 20°S, 85°W under the stratus clouds west of northern Chile is being maintained to provide ongoing, climate-quality records of surface meteorology, of air-sea fluxes of heat, freshwater, and momentum, and of upper ocean temperature, salinity, and velocity variability. The Stratus Ocean Reference Station (ORS Stratus) is supported by the National Oceanic and Atmospheric Administrations (NOAA) Climate Observation Program. It is recovered and redeployed annually, with cruises that have come between October and December. During the October 2006 cruise of NOAA's R/V Ronald H. Brown to the ORS Stratus site, the primary activities where recovery of the Stratus 6 WHOI surface mooring that had been deployed in October 2005, deployment of a new (Stratus 7) WHOI surface mooring at that site, in-situ calibration of the buoy meteorological sensors by comparison with instrumentation pub on board by staff of the NOAA Earth System Research Laboratory (ESRL, formerly ETL), and observations of the stratus clouds and lower atmosphere by NOAA ESRL. A buoy for the Pacific tsunami warning system was also serviced in collaboration with the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA). The old DART (Deep-Ocean Assessment and Reporting of Tsunami) buoy was recovered and a new one deployed which carried IMET sensors and subsurface oceanographic instruments. Argo floats and drifters were also launched and CTD casts carried out during the cruise. The ORS Stratus buoys are equipped with two Improved Meteorological (IMET) systems, which provide surface wind speed and direction, air temperature, relative humidity, barometric pressure, incoming shortwave radiation, incoming longwave radiation, precipitation rate, and sea surface temperature. The IMET data are made available in near real time using satellite telemetry. The mooring line carries instruments to measure ocean salinity, temperature, and currents. The ESRL instrumentation used during the 2006 cruise included cloud radar, radiosonde balloons, and sensors for mean and turbulent surface meteorology. Stratus 7 also received a new addition to its set of sensors: a partial CO2 detector from the Pacific Marine Environmental Laboratory (PMEL). Aerosol measurements were also carried out onboard RHB by personnel of the University of Hawaii. Finally, the cruise hosted a teacher participating in NOAA's Teacher at Sea Program.

Description: Funding was provided by the National Oceanic and Atmospheric Administration under Grant No. NA17RJ1223.

Description: 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 coordinated part of the HOT program and contribute 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 22.75N 158W by successive mooring turnarounds. These observations will be used to investigate air-sea interaction processes related to climate variability. The first WHOTS mooring (WHOTS-1) was deployed in August 2004. WHOTS-1 was recovered and WHOTS-2 deployed in July 2005. This report documents recovery of the WHOTS-2 mooring and deployment of the third mooring (WHOTS-3) at the same site. Both moorings used Surlyn foam buoys as the surface element and were outfitted with two Air-Sea Interaction Meteorology (ASIMET) systems. Each system measures, records, and transmits via Argos satellite, the surface meteorological variables necessary to compute air-sea fluxes of heat, moisture, and momentum. WHOTS-2 was equipped with one Iridium data transmitter, and WHOTS-3 had two Iridium data transmitters. In cooperation with R. Lukas of the University of Hawaii, the upper 155 m of the morrings were outfitted with oceanographic sensors for the measurement of temperature, conductivity, and velocity. The WHOTS mooring turnaround was done on the Scripps Institution of Oceanography ship Revelle, Cruise AMAT-07, by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution and Roger Lukas’group at the University of Hawaii. The cruise took place between 22 and 29 June 2006. Operations on site were initiated with an intercomparison of shipboard meteorological observations with the WHOTS-2 buoy. Dr. Frank Bradley, CSIRO, Australia, assisted with these comparisons. This was followed by recovery of the WHOTS-2 mooring on 24 June. A number of recovered instruments were calibrated by attaching them to the rosette frame of the CTD. Shallow CTD profiles were taken every two hours for 12 hours on the 25th of June. A fish trap was deployed on June 25th by John Yeh, a University of Hawaii graduate student. The WHOTS-3 mooring was deployed on 26 June at approximately 22°46'N, 157°54'W in 4703 m of water. A ship-buoy intercomparison period and series of shallow CTDs followed along with a second deployment of the fishtrap. A NOAA Teacher-At-Sea, Diana Griffiths, and a NOAA Hollings Scholar, Terry Smith, participated in the cruise. This report describes the mooring operations, some of the pre-cruise buoy preparations and CTD casts taken during the cruise, the fish trap deployments, and the experiences of the Teacher-at-Sea and Hollings Scholar.

Description: Funding was provided by the National Oceanic and Atmospheric Administration under grant No. NA17RJ1223 for the Cooperative Institute for Climate and Ocean Research (CICOR).