Dr. Robert A. Weller and Dr. Albert J. Plueddemann, Co-PIs.
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
Program Managers: Mike Johnson, Joel Levy, Climate Observation Program
Related NOAA Strategic Plan Goal:
Goal 2 - Understand Climate Variability and Change to Enhance Society’s Ability to Plan and Respond
The goal of these related observational projects is to maintain long-term surface moorings, known as Ocean Reference Stations, as part of the integrated ocean observing system. These Ocean Reference Stations collect long time series of accurate observations of surface meteorology and upper ocean variability in regions of key interest to climate studies. The resulting meteorological and oceanographic observations provide a set of high quality air-sea fluxes of heat, freshwater and momentum. The scientific rationale for the collection of these flux products is manifold: 1) to describe the upper ocean variability and the local response to atmospheric forcing; 2) to motivate and guide improvement to atmospheric, oceanic, and coupled models; 3) to calibrate and guide improvement to remote sensing products and capabilities; and 4) to provide anchor points for the development of new, basin scale fields of the air-sea fluxes. Model, satellite, and climatological fields of surface meteorology and air-sea fluxes have large errors; high quality, in-situ time series are the essential data needed to improve our understanding of atmosphere-ocean coupling and to build more accurate global fields of air-sea fluxes.
Under this effort three sites are being maintained: the site at 20°S, 85°W under the stratus cloud deck off northern Chile (Stratus), the Northwest Tropical Atlantic Station (NTAS) at 15°N, 51°W, and a site north of Hawaii near the Hawaii Ocean Timeseries (HOT) site known as the WHOI Hawaii Ocean Time-series Station or WHOTS at 22.75°N, 158°W. Moorings at the Stratus and NTAS sites were initially deployed and serviced annually under NOAA OGP support; these sites have now transitioned to long-term Ocean Reference Stations. WHOTS was established in 2004, in collaboration with investigators that have made shipboard and moored observations in that region in recent years. In the management of the Ocean Reference Stations project, four tasks have been identified. First, there is the engineering, oversight, and data management (Task I). Second, the maintenance of the Stratus site (Task II), for which the sixth year of operation was successfully completed. Third, maintenance of the NTAS site (Task III) for which the sixth year of operation was completed. Fourth, maintenance of the WHOTS site, (Task IV), for which the third year of operation was completed. Progress on each of the Tasks is reported in more detail below.
Task I: Engineering, oversight and data:
The oversight task coordinates the common data tasks for the three sites. Oceanographic (velocity, temperature, salinity) and surface meteorological data (wind speed and direction, air and sea surface temperature, rain, incoming shortwave and longwave, relative humidity, and barometric pressure) are processed and stored on disks attached to our workstations. Hourly meteorological data are transmitted via Argos telemetry and made available via an FTP server and a website with download capability. Subsurface data acquired via Iridium from the NTAS site is also collected and made available. We maintain a public access archive of Upper Ocean Processes (UOP) Group data from mooring deployments.
As we look ahead to adding new sensors to the meteorological suite and/or telemetering subsurface data, using Argos becomes increasingly untenable due to data rate limitations. More importantly, we have found that the Argos transmissions introduce noise in some sensors and can degrade data quality. The trials with an Iridium modem on the WHOTS and NTAS buoys indicate that meteorological data can be successfully packaged by the controller, sent via Iridium short-burst messaging and received on shore as an email attachment. We have completed and implemented for the Iridium telemetry an automated, shore-based decoding and processing system. At present we bear the costs of the Iridium data telemetry, and cost constraints prevent us from implementing Iridium on Stratus and NTAS. Should NOAA arrange for a tariff agreement for Iridium as for Argos, we would be able to shift over to Iridium.
We continue to partner with Dr. Chris Sabine (NOAA PMEL) to incorporate his pCO2 instrumentation on board our buoys. In prior years pCO2 measurement was limited to the Stratus buoy, but this year we arranged with Sabine to transfer a system from the MOSEAN buoy to the WHOTS buoy deployed in June 2007. Thus, pCO2 is being now being measured at two ORS sites. The Stratus buoy is also being used as the site where we are testing the addition of sensors to measure surface waves. This is being done in collaboration with the National Data Buoy Center (NDBC), with NDBC providing hardware and guidance on how to implement wave measurements on the ORS buoys.
The major engineering initiative this year has been the implementation at the NTAS site of the capability to collect and telemeter data in near-real time from subsurface instruments on the mooring line. An electro-mechanical (EM) interface was developed for subsurface data telemetry on ORS moorings. Previous hardware designs developed separately for inductive and acoustic telemetry by the WHOI Applied Ocean Physics and Engineering Department were adapted to create a robust, reusable EM interface supporting both inductive and acoustic telemetry. The mechanical components of this interface (Fig. I-1) include a specially designed universal joint, an upper flanged spacer, a six-meter electro-mechanical “compliant section”, a lower flanged spacer, and a wire coupling assembly that includes a bell mouth and socket to accept a specially terminated shot of 7/16” jacketed mooring wire and space for an acoustic modem to be mounted alongside (acoustic telemetry was not used for this deployment).
The UOP Group implemented a communications system to support inductive telemetry. The system was built around an Air-Sea Interaction Meteorology (ASIMET) controller board, and included a Seabird Inductive Modem (IM) and an Iridium Communication Module (ICM). The controller uses only a few milliwatts, and runs continuously, while the IM and ICM, which use considerably more power, are turned on intermittently. The controller powers up the IM every 5 minutes and the IM awakens the modems of all attached instruments. The controller then polls fixed addresses on the IM loop and places up to 4 hours of sensor data, obtained at 5 minute intervals, in a circular buffer. After 4 hours the ICM turns on, requests the most recent buffered data, creates and logs 4 one-hour averages, formats the averages as a Short Burst Data (SBD) message, and sends the SBD message via Iridium.
SBD messages are received and processed on a workstation at WHOI by an automated shell script which invokes a series of processing programs when new data arrives. The software suite extracts the data payloads from email attachments sent to WHOI by the Iridium SBD system, decodes the binary data, and produces data listings and plots on the UOP web site within minutes of data being transmitted from the buoy (see Data Links: Iridium at http://uop.whoi.edu/projects/NTAS/ntasdata.htm).
Task II: Stratus Site:
The stratus surface mooring was originally deployed under a previous grant (from the Pan American Climate Studies) in October 2000. It has been annually redeployed and recovered since that time. During the deployments, hourly-averaged surface meteorology was available from the buoy in near real time via Service ARGOS and a WHOI ftp site. Data exchanges were made with ECMWF, NCEP and others to examine numerical weather prediction model performance and examine air-sea fluxes under the stratus clouds. The telemetered meteorological data are also available via the website maintained for this site (http://uop.whoi.edu/stratus). Internally recorded 1-minute meteorological data as well as the oceanographic data, which are only internally recorded, were downloaded from the recovered instrumentation. Data recovery was good, post-calibrations are being done, and data files have been shared with colleagues. Preliminary cruise reports are filed with the State Department soon after the cruise; final documentation that goes to foreign observers and the State Department includes copies of the underway data and a final cruise report (Bigorre et al., 2007). Telemetry from the buoy presently deployed indicates that it is on station and both meteorological systems are functioning well.
Work this year included deploying the new and recovering the old mooring, doing calibrations (both pre and post-deployment), data processing, writing cruise reports, preparing mooring hardware and instrumentation for the new deployment and cleaning and assessing the recovered equipment. The FY2007 deployment was carried out aboard the R/V Ronald H. Brown which sailed from Rodman, Panama on October 9, 2006 and arrived into Valparaiso, Chile on October 27, 2006.
The planning and observational preparation for the cruise begins many months before the deployment. During the summer of 2006 instruments were gathered and placed on the new mooring buoy for testing. This testing of the instrumentation while mounted on the buoy, and exposed outdoors, is important for the proper gauging of accuracy and reliability. This on-going burn-in period typically lasts three or more months. In September of 2006, members of the UOP group loaded the R/V Ron Brown in Charleston.
The Stratus 7 buoy was deployed first due to the lack of space on deck to have both the recovered Stratus 6 buoy and the Stratus 7 buoy aboard at the same time. The Stratus 7 buoy was deployed October 16, 2006. The Stratus 6 mooring was recovered on October 18th with no undue problems. As in some previous years, several upper ocean instruments were fouled by fishing line. In response to this, we have shifted our mechanical current meters to deeper sites and added acoustic current meters to the shallow locations on the mooring; these acoustic current meters suffer much less data loss associated with fising line.
After the work at the Stratus buoy, the Brown sailed east to the site of the Chilean tsunami buoy. The existing DART surface buoy and bottom package were recovered on October 22, 2006. A new bottom package and surface buoy were deployed on October 23.
On the Stratus buoy we measure air temperature, sea surface temperature, relative humidity, incoming shortwave and longwave radiation, wind speed and direction, rain rate, and barometric pressure. On the mooring line the instrumentation is concentrated in the upper 300m and measures temperature, salinity, and velocity. During the deployment, high data rate (up to 1 sample per minute) data are stored in each instrument. The internally recorded data goes through processing, has calibration information applied, and is subject to preliminary analyses before being made publicly available on our website. In the interim, preliminary versions are made available upon request.
Hourly surface meteorological data are archived at WHOI, arriving within hours of when it was observed. These data are exchanged in near real time with ECMWF and NCEP; they in turn provide operational data at the grid point nearest the model. It is also shared with the Chilean Navy (SHOA). The same data are shared with CLIVAR investigators, especially modelers interested in the Stratus region, with VAMOS investigators in the U.S. and in South America. It is also sent to Peter Glecker at PCMDI for use in the SURFA project. This meteorological data are used to assess the realism of operational atmospheric models in the stratus region. Once per minute as well as hourly surface meteorological time series are provided to the VOCALS and other investigator communities (including Sandra Yuter, Chris Bretherton, Meghan Cronin) after recovery. The surface meteorological data have been made available to the satellite community (including radiation – Langley, winds – Remote Sensing Systems and JPL, SST – Dick Reynolds, all variables – the SEAFLUX project). The oceanographic data are being used by Weller to investigate air-sea coupling and upper ocean variability under the stratus deck (Colbo and Weller 2007a). The initial archive is maintained by the Upper Ocean Processes Group at WHOI, which runs a public access server for their mooring data. We are providing the data to Ocean SITES (http://www.oceansites.org/). This year an effort was made to quality control and share the first 6 years of data. This was done in part to facilitate planning of the VOCALS (VAMOS Ocean Cloud Atmosphere Land Study) to be conducted in conjunction with the October 2008 Stratus cruise. Data files and plots were shared in support of proposal writing and pilot studies in advance of VOCALS.
Both before the recovery of the old buoy and after the deployment of the new buoy, in situ comparisons of the ship’s and buoys’ twin meteorological sensors were carried out. These comparisons have been a crucial component of the post-recovery data processing, particularly for sensitive instruments that may suffer damage during the return shipment to WHOI. Extensive shipboard meteorological and air-sea flux instrumentation was installed on the Ron Brown and operated by Chris Fairall from the NOAA Earth System Research Laboratory (ESRL) in Boulder, CO. The air-sea flux system consists of a fast turbulence system with ship motion corrections, a mean T/RH sensor, solar and IR radiometers, a near surface sea surface temperature sensor, a Particle Measurement Systems (PMS) Lasair-II aerosol spectrometer, and an optical rain gauge. Colbo and Weller (2007b) summarized what has been learned from this work about the accuracy of the moored meteorological sensors and the resultant air-sea flux estimates.
ESRL also operated three remote systems: a Vaisala CT-25K cloud base ceilometer, a 35 GHz vertically pointed Doppler cloud radar, and a 20.6 - 31.65 GHz microwave radiometer. ESRL has an integrated system in a seatainer that includes a Doppler Ka-band cloud radar (MMCR) and a microwave radiometer. The system can be used to deduce profiles of cloud droplet size, number concentration, liquid water concentration etc. in stratus clouds. If drizzle (i.e., droplets of radius greater than about 50 µm) is present in significant amounts, then the microphysical properties of the drizzle can be obtained from the first three moments of the Doppler spectrum. The radar is extremely sensitive and can detect most tropical cirrus and fair weather cumulus clouds. The Doppler capability can also be used to measure in-cloud vertical velocity statistics.
The Stratus cruises serve the wider scientific community by providing a platform on which to study the regional ocean. Additional researchers who participated in collaborative research or benefited from shared ship time in FY2007 have come from many institutions: NOAA Earth System Research Laboratory (ESRL), NOAA Pacific Marine Environmental Laboratory (PMEL), Servicio Hydrografico y Oceanografico de la Armada (Chile), University of Concepcion (Chile), University of Colorado, University of Miami, and University of Buenos Aires.
These collaborations have included: enhanced regional surface flux and lower atmosphere surveys, both offshore and within Chilean coastal waters (NOAA ESRL, U. Miami, U. Colorado), extensive hydrographic surveys with CTDs and XBTs (multi-user), and the support of maintaining a tsunami warming buoy (Chilean Navy).
The 2006 stratus cruise also hosted a teacher from NOAA’s Teachers-at-Sea program (Brett Hoyt). During the cruise, the teacher assisted with science operations including mooring deployments and recoveries. He also wrote logs, took photos, and interviewed science members and crew. This information was used to communicate the experience.
To further support ground-truthing of satellite data and increased understanding of the ocean in the eastern South Pacific, drogued surface drifters and profiling ARGO floats were deployed in the South Pacific along the cruise track.
Colbo, K and R. A. Weller, 2007a: The variability and heat budget of the upper ocean under the Chile-Peru stratus. J. Mar. Res., in press.
Colbo, K. and R. A. Weller, 2007b: The accuracy of the IMET sensor package. J. Atmos. Oceanic Technol., in review.
Bigorre, S. R. Weller, J. Lord, S. Whelan, N. Galbraith, D. Wolfe, L. Bariteau, V. Ghate, U. Zajaczkovski, A. Vera, S. Maenner, and B. Hoyt, 2007. Stratus Ocean Reference Station (20°S, 85°W), Mooring Recovery amd Deployment Cruise, R/V Romald H. Brown, Cruise 06-07, October 9 – October 27, 2006. Woods Hole Oceanogr. Inst. Tech. Rept. WHOI-2007-01, 154 pages.
Cronin, M. F., N. A. Bond, C. Fairall, and R. A. Weller, 2006. Surface cloud forcing in the east Pacific stratus deck/cold tongue/ITCZ complex. J. Climate, 19(23), 392-409.
Hutto, L., R. Weller, J. Lord, J. Smith, P. Bouchard, C. Fairall, S. Pezoa, L. Bariteau, J. Lundquist, V. Ghate, R. cstro, and C. Cisternas, 2006: Stratus Ocean Reference Station (20o S, 85o W), Mooring Recovery and Deployment Cruise: R/V Ronald H. Brown Cruise 05-05, September 26 – October 21, 2005. Woods Hole Oceanogr. Inst. Tech. Rept., WHOI-2006-06.
Cronin, M. F., N. A. Bond, C. W. Fairall, and R. A. Weller, 2006: Surface Cloud Forcing in the East Pacific Stratus Deck/Cold Tongue/ITCZ Complex. J. Climate, 19, 392-409, doi: 10.1175/JCLI3620.1.
Colbo, K., R. Weller, J. Lord, J. Smith, P. Bouchard, C. Fairall, D. Wolfe, E. Serpetzoglou, A. G. V. Tisandie, J. F. S. Bustos, F. Bradley, and J. Tomlinson 2005: Stratus Ocean Reference Station (20o S, 85o W), Mooring Recovery and Deployment Cruise: R/V Ronald H. Brown Cruise 12-04, December 5 – December 23, 2004. Woods Hole Oceanogr. Inst. Tech. Rept., WHOI-2005-06.
Cronin, M. F., N. Bond, C. Fairall, J. Hare, M. J. McPhaden, R. A. Weller. Enhanced oceanic and atmospheric monitoring underway in Eastern Pacific. EOS, Transactions, AGU, 83(19), pages 205, 210-211, 7 May 2002.
Hutto, Lara, Robert A. Weller, Jeff Lord, Jason Smith, Jim Ryder, Nan Galbraith, Chris Fairall, Scott Stalin, Juan Carlos Andueza and Jason Tomlinson, 2003. Stratus Ocean Reference Station (20o S, 85o W), Mooring Recovery and Deployment Cruise: R/V Revelle Cruise Dana 03, November 10 – November 26, 2003. Woods Hole Oceanogr. Inst. Tech. Rept., WHOI-2004-04.
Hutto, Lara, Robert A. Weller, Jeff Lord, James Ryder, Alice Stuart-Menteth, Nancy Galbraith, Paul Bouchard, Jenny Maturana, Oscar Pizarro, and Jaime Letelier, 2003. Long-Term Evolution of the Coupled Boundary Layers (Stratus) Mooring Recovery and Deployment Cruise Report R/V Melville. Technical Report, WHOI-2003-02, UOP-2003-01.
Lucas, Lisan E., Bryan S. Way, Robert A. Weller, Paul R. Bouchard, William M. Ostrom, Albert S. Fischer, Carlos F. Moffat, Wolfgang Schneider, Melanie R. Fewings, 2001. Long-Term Evolution and Coupling of the Boundary Layers in the Stratus Deck Regions of the Eastern Pacific (STRATUS). Technical Report, WHOI-2001-04, UOP-2001-01.
Vallée, Charlotte, Kelan Huang, Robert Weller, 2002. Long-Term Evolution and Coupling of the Boundary Layers in the Stratus Deck Regions of the Eastern Pacific (STRATUS) Data Report. Technical Report, WHOI-2002-06, UOP-2002-03.
Vallée, Charlotte, Robert A. Weller, Paul R. Bouchard, William M. Ostrom, Jeff Lord, Jason Gobat, Mark Pritchard, Toby Westberry, Jeff Hare, Taneil Uttal, Sandra Yuter, David Rivas, Darrel Baumgardner, Brandi McCarty, Jonathon Shannahoff, M.A. Walsh, Frank Bahr, 2002. Long-Term Evolution of the Coupled Boundary Layers (STRATUS) Mooring Recovery and Deployment Cruise Report, NOAA Research Vessel R H Brown, Cruise RB-01-08, 9 October – 25 October 2001. Technical Report, WHOI-2002-02, UOP-2002-01.
Seminars and Presentations:
“VOCALS Ocean Science and Implementation” VOCALS Planning Workshop, Snatiago, Chile, April 2006
“Ocean surface heat fluxes,” presentation at Office of Climate Observations annual Workshop, May 2006
“Climate observations for research”, presentation at Office of Climate Observations annual Workshop, May 2006
“Climate quality buoy and ship observations”, High Resolution Marine Meteorology Workshop, Tallahassee, March 2003
”The variability under the stratus deck - surface mooring results”, VAMOS Panel Meeting 7, Guayaquil, Ecuador, Feb 2004
Ocean Observations Panel for Climate (OOPC), SOC, UK Report on the Status of Air-Sea Fluxes and the WCRP Working Group, June 2004
“How Accurate are Surface Meteorology Measurements from a Buoy?”, First International CLIVAR Science Conf., 21-25 June 2004, Baltimore, MD (poster).
Task III: NTAS Site:
The Northwest Tropical Atlantic Station (NTAS) project for air-sea flux measurement was conceived in order to investigate surface forcing and oceanographic response in a region of the tropical Atlantic with strong SST anomalies and the likelihood of significant local air-sea interaction on seasonal to decadal time scales. The strategy is to maintain a meteorological measurement station at approximately 15o N, 51o W through successive (annual) turn-arounds of a surface mooring. Redundant meteorological systems measure the variables necessary to compute air-sea fluxes of heat, moisture and momentum using bulk aerodynamic formulas.
NTAS has two primary science objectives: 1) Determine the air-sea fluxes of heat, moisture and momentum in the northwest tropical Atlantic using high-quality, in-situ meteorological measurements from a moored buoy. 2) Compare the in-situ fluxes to those available from operational models and satellites, identify the flux components with the largest discrepancies, and investigate the reasons for the discrepancies. An ancillary objective is to compute the local (one-dimensional) oceanic budgets of heat and momentum and determine the degree to which these budgets are locally balanced.
A mooring turn-around cruise was conducted on the NOAA ship Ronald H. Brown in order to retrieve the existing mooring (NTAS-6, deployed 25 February 2006) and replace it with a new mooring (NTAS-7). In preparation for this cruise, three Air-Sea Interaction Meteorology (ASIMET) systems were assembled and tested. Two systems, comprised of the best performing sensors, were mounted on the newly developed 2.7 m modular ORS buoy in preparation for deployment. The NTAS-7 mooring was deployed on 19 April 2007 and the NTAS-6 mooring was recovered on 24 April. The period between deployment and recovery was dedicated to a comparison of the two buoy systems, with the shipboard system as an independent benchmark. To ensure high-quality meteorological data, all NTAS-7 sensors were calibrated prior to deployment, and NTAS-6 sensors will be post-calibrated. A cruise report is in preparation.
In addition to the NTAS mooring turnaround, the 2007 NTAS cruise accommodated mooring service work for NDBC, site servicing for the Meridional Overturning Variability Experiment (MOVE), Argo drifter deployments, and testing of a novel air-sea heat flux drifter developed by Jim Boyle of W. Connecticut State University.
As a part of outreach and education for the ORS project this year, two interns from the Joint Oceanographic Institutions (JOI) were hosted on the NTAS-7 cruise. The interns conceived, prepared and implemented a live “expedition” web site documenting NTAS science, technology, and cruise operations (http://joiserver.joiscience.org/mission1551). This effort was successful, with an estimated 2,300 first-time visitors to the site during the cruise, along with 4 press releases, 4 newspaper articles, 15 web links from other sites, and an Oceanus article.
Preliminary processing of the NTAS-5 meteorological data has been completed. Data return was very good, with all sensors except one wind module operating for the complete deployment period. The comparison period showed very encouraging results, indicating little degradation of NTAS-5 sensor performance after one year at sea. After post-calibration of the sensors, the corrected, 1-min data will be used for further analyses. The uncorrected, hourly Argos data from NTAS-4, 5 and 6 are available on-line from the Upper Ocean Processes (UOP) group web site (http://uop.whoi.edu/projects/NTAS/ntas.htm). At present, about 5 months of hourly meteorological data from NTAS-7 are also available for examination on the UOP web site. Preliminary evaluation indicates that all NTAS-7 sensors are performing as expected. Meteorological sensors from NTAS-1 through 5 have been post-calibrated, and NTAS-1 and 2 data have been post-processed. Hourly averaged files from the post-processed data sets are available on the UOP web page. The 1 min data are being used as the basis for air-sea flux computations using bulk formulas.
For the telemetry trial on NTAS-7, the inductively coupled mooring line was outfitted with instruments from the UOP Group inventory which contained inductive modems. Three Seabird SBE-37s were deployed at 25, 45 and 65 m and a Sontek Argonaut current meter was deployed at 14 m. Hourly averages of subsurface data were obtained at 4 hour intervals via Iridium. The telemetered message is a subset of the data returned from inductive polling. For example, only temperature and conductivity (later converted to salinity) are transmitted from the SBE-37s, and the Argonaut data record is reduced to just 8 variables. The inductive coupler on the current meter failed soon after deployment, but temperature and salinity data are being obtained routinely and are available from the UOP web site.
Publications and Presentations (cumulative)
Goldsmith, R.A. and A.J. Plueddemann, 2002. Moored buoy site evaluations, Marine Geography, J. Breman, Ed., ESRI Press, pp 73-77.
Halpern, D., R. Weller and A. Plueddemann, 2006, Ocean Atmosphere Interfaces in Climate, Solar Radiation and Climate Experiment (SORCE) Science Meeting, San Juan Island, WA.
Plueddemann, A., 2003, In-situ meteorology from the Northwest Tropical Atlantic Station, Proc. U.S. CLIVAR Atlantic Conf., Wash, DC, pp 9-13.
Plueddemann, A.J., 2003. In-situ meteorology and air-sea fluxes in the Northwest Tropical Atlantic, NOAA Climate Observation Program Workshop, Silver Spring, MD (poster).
Plueddemann, A.J., 2003. In-situ meteorology and air-sea fluxes in the Northwest Tropical Atlantic, NOAA Climate Observation Program Workshop Report, 13-15 May 2003, Silver Spring, MD.
Plueddemann, A., 2004, Multi-year, in-situ surface fluxes in the northwest tropical Atlantic, First International CLIVAR Science Conf., 21-25 June 2004, Baltimore, MD (poster).
Plueddemann, A.J., 2007. Ocean Reference Stations: An Air-Sea Flux Reference Network, MTS/IEEE Oceans ’06, Boston, MA, (talk).
Plueddemann, A., F. Bahr, D. Hosom and R. Weller, 2006. Surface meteorology from volunteer observing ships, First Joint GOSUD/SAMOS Workshop, 2-4 May, Boulder, CO (poster).
Plueddemann, A., F. Bahr, D. Hosom and R. Weller, 2006. Surface meteorology from volunteer observing ships, NOAA Office of Climate Observation Annual System Review, Silver Spring, MD (poster).
Plueddemann, A., F. Bahr, D. Hosom and R. Weller, 2007, Spatial Variability in Surface Meteorology from a VOS and the ECMWF model, NOAA Office of Climate Observation Annual System Review, Silver Spring, MD, (poster).
Plueddemann, A.J., N.R. Galbraith, W.M. Ostrom, G.H. Tupper, R.E Handy, and J.M. Dunn, 2001. The Northwest Tropical Atlantic Station (NTAS): NTAS-1 Mooring Turnaround Cruise Report. WHOI Tech. Rept. WHOI-2001-07, 55 pp.
Plueddemann, A.J., W.M. Ostrom, N.R. Galbraith, P.R. Bouchard, G.H. Tupper, J.M. Dunn and M.A. Walsh, 2002. The Northwest Tropical Atlantic Station (NTAS): NTAS-2 Mooring Turnaround Cruise Report, WHOI Tech. Rept. WHOI-2002-07, 68pp.
Plueddemann, A.J., W.M. Ostrom, N.R. Galbraith, J.C. Smith, J.R. Ryder, J.J. Holley and M.A. Walsh, 2003. The Northwest Tropical Atlantic Station (NTAS): NTAS-3 Mooring Turnaround Cruise Report, WHOI Tech. Rept. WHOI-2003-04, 69 pp.
Plueddemann, A. J., W. M. Ostrom, N. R. Galbraith, P. R. Bouchard, B.P. Hogue, B. R. Wasnewski and M. A. Walsh, 2006. The Northwest Tropical Atlantic Station (NTAS): NTAS-4 mooring turnaround cruise report. WHOI Tech. Rept. WHOI-2006-09, 65 pp.
Plueddemann, A.J. and R.A. Weller, 2004. Meteorology and air-sea fluxes from ocean reference stations, NOAA Office of Climate Observation Workshop, 12-14 April 2004, Silver Spring, MD (poster).
Plueddemann, A.J. and R.A. Weller, 2005. Meteorology and air-sea fluxes from ocean reference stations, NOAA Office of Climate Observation Workshop, 25-27 April 2005, Silver Spring, MD (talk).
Plueddemann, A. J., R. A. Weller, R. Lukas, J. Lord, P. R. Bouchard and M. A. Walsh, 2006. WHOI Hawaii Ocean Timeseries Station (WHOTS): WHOTS-2 Mooring turnaround cruise report, WHOI Tech. Rept. WHOI-2006-08, 68 pp.
Plueddemann, A., R. Weller, J. Lord, N. Galbraith, P. Bouchard and S. Whelan, 2007, Inductive Telemetry for UOP Ocean Reference Stations, NOAA Office of Climate Observation Annual System Review, Silver Spring, MD, (poster).
Upper Ocean Processes Group, 2007. Inductive telemetry for UOP Ocean Reference Station moorings, UOP Technical Note, August 2007, http://uop.whoi.edu/techdocs/TN-telemetry-NTAS-Aug07.pdf
Weller, R, A. Plueddemann, D. Hosom, R. Payne, J. Smith F. Bahr and F. Bradley, 2003. The quality of surface meteorology from unattended buoys and volunteer observing ships, CLIMAR-II Workshop on Advances in Marine Meteorology, Brussels, Belgium, 17-22 November 2003 (poster).
Weller, R, L. Yu, A. Plueddemann, D. Hosom, and S. Sathiyamoorthy, 2003. Synthesis of basin-scale air-sea flux fields, CLIMAR-II Workshop on Advances in Marine Meteorology, Brussels, Belgium, 17-22 November 2003 (poster).
Task IV: Hawaii Site:
The Hawaii Ocean Time-series (HOT) site, 100 km north of Oahu, Hawaii, has been occupied since 1988 as a part of the World Ocean Circulation Experiment (WOCE) and the Joint Global Ocean Flux Study (JGOFS). Among the HOT science goals are to document and understand seasonal and interannual variability of water masses, relate water mass variations to gyre fluctuations, and develop a climatology of high-frequency physical variability in the context of interdisciplinary time series studies. The primary intent of the WHOI Hawaii Ocean Timeseries Station (WHOTS) mooring is 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. It is expected that establishment of the WHOTS mooring will accelerate progress toward understanding multidisciplinary science at the site, provide an anchor site for developing air-sea flux fields in the Pacific, and provide a new regime in which to examine atmospheric, oceanic, and coupled model performance as well as the performance of remote sensing methods.
The first ORS mooring was deployed at the HOT site in August 2004, representing a two year advancement of the timetable originally proposed (financial support for this acceleration was provided by the NOAA Office of Climate Observations as an Add Task). The observational strategy is to maintain a surface mooring at approximately 22.75° N, 158° W, instrumented to obtain meteorological and upper ocean measurements, through successive (annual) turnarounds done in cooperation with HOT investigators. Redundant meteorological systems on the surface buoy measure the variables necessary to compute air-sea fluxes of heat, moisture and momentum using bulk aerodynamic formulas. Subsurface oceanographic sensors on the mooring are being provided through cooperation with Roger Lukas (U. Hawaii; funded by the National Science Foundation). The WHOTS mooring is nearby the Multi-disciplinary Ocean Sensors for Environmental Analyses and Networks (MOSEAN) mooring of Tommy Dickey (U.C. Santa Barbara; funded by the National Oceanographic Partnership Program). We have established links with U. Hawaii and the MOSEAN group to improve the efficiency of field logistics. This year we also worked with Chris Sabine to implement pCO2 measurements on the WHOTS buoy given uncertainty about whether the MOSEAN mooring would be redeployed.
A mooring turn-around cruise was conducted during June and July 2007 in order to retrieve the existing mooring (WHOTS-3, deployed June 2006) and replace it with the new mooring (WHOTS-4). This year, we operated for the first time from the U. Hawaii ship Kilo Moana. In preparation for this cruise, three ASIMET systems were assembled and tested. Two systems, comprised of the best performing sensors, were mounted on a 2.7 m modular ORS buoy in preparation for deployment. The WHOTS-4 mooring was deployed on 25 June 2007, and the WHOTS-3 mooring was recovered on 28 June. The period between deployment and recovery was dedicated to an intercomparison of the buoy and shipboard meteorological systems. The WHOTS-3 mooring included Iridium meteorological data telemetry systems, developed under the ORS Engineering, Oversight and Data project. These systems were not deployed in WHOTS-4. However, the Iridium subsurface telemetry system used on NTAS was based on the successful WHOTS 2 and 3 deployments. To ensure high-quality meteorological data, all WHOTS-4 sensors were calibrated prior to deployment, and WHOTS-3 sensors will be post-calibrated. A cruise report is in preparation.
Preliminary processing of the WHOTS-1 and 2 meteorological data is in progress. Data return was good. The WHOTS-3/4 intercomparison period showed encouraging results. Extended mounts for air temperature/relative humidity sensors were used on both buoys, and no evidence of diurnal heating was seen. Commercial bird-deterrent spikes deployed on the WHOTS-3 buoy significantly reduced contamination and shadowing from birds landing on the buoy, and a similar installation was used for WHOTS-4. The hourly Argos meteorological from WHOTS 1-4 data are available on-line from the UOP group web site (http://uop.whoi.edu/projects/WHOTS/whotsdata.htm).