Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
  • BCO-DMO Processing Description
  • Problem Description
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Hydrographic measurements from discrete water bottle samples collected at Hydrostation S located 25 km SE of Bermuda (32°10' N, 64°30' W).  Measurements have been collected since 1954 at the Panulirus hydrographic stations and include salinity, temperature, sigma theta, and dissolved oxygen.

Water samples have been collected at the Panulirus (aka Hydrostation S) site, located about 25 kilometers southeast of Bermuda, since 1954 when Henry 'Hank' Stommel and co-workers initiated repeat biweekly hydrographic measurements and observations. 

The bottle samples were originally collected from Hydrocasts using Niskin bottles and reversing thermometers for temperature and thermometric depth. CTD profiling was introduced to the Panulirus project in October 1988 and the methodology used for collection of CTD data and integrated water samples has been consistent with those used on the Bermuda Atlantic Time series Study (see Knap et al., 1997). The standard sample parameter list has been mostly consistent for the full time-series record and includes temperature, salinity, and dissolved oxygen. Since October 1988 (cruise #643), data and samples have been collected using a SeaBird 911+ CTD and an integrated Niskin rosette system. The largest data gap of almost one year was due to the loss of all the Niskin bottles and reversing thermometers following a break in the hydro wire on station #463 (April 1979). 

Further information on the data collection from 1954-1984 can be obtained in the Joint WHOI and BBSR (BIOS) data report 'Station S off Bermuda, Physical measurements 1954-1988 (WHOI contribution No. 6894)' by Metcalf et al. (1988). 

Ship information:
-  R/V Panulirus I (June 1954-May 1967)
-  R/V Panulirus II(June 1967-December 1982)
-  R/V Weatherbird I (Jan 1983 - September 1989)
-  R/V Weatherbird II (October 1989 - February 2005)
-  R/V Atlantic Explorer (May 2006 - Present)

Prior to the arrival of the vessel Weatherbird I in 1983, station occupation during winter months was limited due to the sea-going capabilities of the former vessels.

Numerous Chief Scientists have carried out the sampling during the cruises: 
William Sutcliffe, David Menzel, John Beers, Albert Brooks Fred Mackenzie, Roger Pocklington, Eric Amos, Byron Morris, John Barnes, Anthony Knap, Timothy Jickells, Rachel Sheriff-Dow, Tony Knap, Rachel Dow, Anthony Michaels, Kjell Gundersen, Rodney Johnson, Ann Close, Paul Lethaby, Julian Mitchell, Vivienne Lochhead, Deborah Lomas, Steven Bell, Jonathan Whitefield, Gwyn Evans, James Sadler, Samuel Monk, Samuel Stevens, Afonso Goncalves, Matt Enright, Fernando Pacheco, Zac Anderson, Claire Medley, Dominic Smith, Rebecca May and Lucinda Derbyshire.

Data was processed, evaluated, and flagged using the following Quality Flag definitions:

• Bottle (Niskin or Go-Flo) quality flags:  -3= suspect, 1= unverified, 2= verified/acceptable
• Parameter data quality flags: 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data

- Imported data from files “hydrostation_bottle_qcmask_v005.txt" and “hydrostation_bottle_v005.txt” into the BCO-DMO data system. Data file imported using missing data identifiers (nd, -999, -999.0, -999.000).
- Joined the two files using join keys of Id, yyyymmdd, latN, and lonW
- Modified parameter names to conform with BCO-DMO naming conventions
- Converted latitude and longitude values to decimal degrees
- Zero-padded the values in the time column and combined with the date column to create a new ISO 8601 DateTime field.
- Using information from the Bottle_ID column, created columns for Cruise, Cast, and Bottle
- Added a field for Vessel
- Renamed the quality flag fields to have the measurement description and moved them to be adjacent to the corresponding measurement columns.

Hydrostation S (also known as Panulirus hydrographic station) is recognized as one of the most important sustained ocean time-series sites in the world.  Located about 25 km southeast of Bermuda in the North Atlantic Ocean, this site has oceanographic measurements dating back to 1954, when Henry Stommel and co-workers initiated repeat biweekly hydrographic observations. 

The most recent project awards and abstracts are listed below.  A detailed history of funding with summary of all project awards for Hydrostation S (Panulirus Hydrographic stations) can be found here (PDF format):
https://datadocs.bco-dmo.org/docs/305/Hydrostation_S/data_docs/Hydrostation_S_funding_history.pdf

Years 70-74:
NSF Award OCE-2122606 Abstract:

This project continues hydrographic observations at Hydrostation S, extending the time-series of ocean data to almost 70 years. Hydrostation S (formerly known as the Panulirus site), located about 25 km southeast of Bermuda in the North Atlantic Ocean, is one of the longest open-ocean hydrographic stations in the world. This program of repeat biweekly hydrographic observations began in 1954 and now, in its seventh decade, has proved to be the catalyst for numerous studies of ocean physics, biological processes and biogeochemistry. Sustained observations of the ocean, such as those from Hydrostation S, remain critically important to establish rates of change to provide quantitative empirical data for myriad regional and global ocean synthesis and modeling of ocean processes and future ocean change. Hydrostation S program and its data are considered as a service to the community, being openly distributed and subsequently have been an invaluable resource in understanding processes and patterns of variability in the ocean, as well as education, mentorship and outreach activities.

The major objective of the proposal is to continue Hydrostation S into the eighth decade with numerous questions related to warming and cooling, salinification and freshening, deoxygenation and insights on biogeochemical changes over time. This program constitutes frequent water column sampling of temperature, salinity, and dissolved oxygen (and indirectly, sampling of important ocean carbon time–series) of the North Atlantic subtropical gyre at the Hydrostation S site. Such work is complementary to other sustained observations such as the Bermuda Atlantic Time–series Study (BATS) and Ocean Flux Program (OFP). The project entails a similar sampling format that has been followed for the past 68 years. Hydrostation S also supports the longest global ocean CO2 and acidification time-series (from 1983 to present).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Years 65-69:
NSF Award OCE-1633125 Abstract:
The physical properties of the ocean from the surface layers to the abyssal water masses are changing in concert with natural and anthropogenically influenced physical forcing and sustained observations of the ocean are critically important to establish these rates of change. One of the longest open-ocean hydrographic stations in the world is maintained at the Hydrostation S site (formerly known as the Panulirus site) located about 25 km southeast of Bermuda in the North Atlantic Ocean. This repeat biweekly hydrographic observations was initiated by Henry Stommel and co-workers in 1954. Now, in its seventh decade, it continues to be recognized as one of the most important sustained ocean time-series and provides an invaluable metric for the long-term state of the North Atlantic subtropical gyre in relation to the meridional overturning circulation, western boundary transport, and gyre recirculation. For example, the upper ocean warming trend has strengthened (about 0.8° C since the 1970's) while the deep Labrador Sea has cooled by a few tenths of a degree. The signature of deoxygenation has been observed at Hydrostation S in the upper ocean (about 7 micro-moles/kg/decade decrease in dissolved oxygen) as well as an intensification and expansion of the oxygen minimum zone. These changes suggest that the North Atlantic subtropical gyre is experiencing deoxygenation as in the Pacific Ocean as a result of increased upper ocean stratification and reduced solubility of oxygen in warmer waters. The Hydrostation S program and its data set are managed as a service to the ocean community, being openly distributed and used as a resource in understanding processes and patterns of variability in the ocean, as well as for education, mentorship and outreach activities. The Hydrostation S project will contribute to the research and training of six research specialists and research technicians at BIOS and contribute to the research projects of at least three Ph.D. students through on-going educational partnership with Princeton University and the University of Southampton in the U.K. The one-day Hydrostation S research cruises are an ideal platform for testing new sensors and for providing hand-on training to undergraduate students enrolled in summer programs.

The Hydrostation S project is designed to address the overarching hypothesis that the physical properties of the upper-ocean to deep-ocean are changing in concert with natural and anthropogenically influenced physical forcing. Sustained observations of the ocean, such as those from Hydrostation S, remain critically important to establish rates of change to provide quantitative empirical data for myriad regional and global ocean synthesis and modeling of ocean processes and future ocean change. The major objective of Hydrostation S into the seventh decade is to continue the frequent water column sampling of temperature, salinity, and dissolved oxygen (and indirectly, sampling of important ocean carbon time?series) of the North Atlantic subtropical gyre. Such work is complementary to other sustained observations such as the Bermuda Atlantic Time-series Study (BATS) and Ocean Flux Program (OFP). As for the past five years, two CTD profiles will be conducted to better capture the deep-water variability while maintaining all the previous discrete depths. The first CTD cast will profile to full ocean depth (3,200-3,500 m) while the second CTD cast will profile from the surface to 500 m to allow for biogeochemical instrumentation not rated for full ocean depth and to support ancillary studies of ocean physics, biological processes and biogeochemistry. A secondary objective will be to build upon the collaborative comparison of physical data collected as part of two autonomous sensor projects. In the latter stages of the project, as ocean glider deployment becomes more sustainable and reliable, collaborative and comparative efforts will be used to test the capability of ocean gliders to provide data of sufficient quality to detect long-term oceanic change in a "virtual" mooring time-series mode. The robust and highly accurate Hydrostation S data will be used to test the capability of emerging technologies over the next five to ten years.