Dataset: CTD data from Hydrostation S

Name: Two decibar averaged CTD profiles collected at the Hydrostation S site in the Sargasso Sea from October 1988 (cruise #60643) through December 2023 (cruise #61465)
Published: 2024-11-01
Keywords: CTD, Hydrostation S, Sargasso Sea, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.860014.8

Spatial Extent: N:32.983 E:-63.081 S:30.154 W:-66.799

Hydrostation S located 25 km SE of Bermuda (32°10' N, 64°30' W)

Temporal Extent: 1988-10-26 - 2023-12-22

Project:

The Panulirus Hydrographic Stations (Hydrostation S) (Hydrostation S)

Principal Investigator:

Nicholas Bates (Bermuda Institute of Ocean Sciences, BIOS)

Co-Principal Investigator:

Rodney J. Johnson (Bermuda Institute of Ocean Sciences, BIOS)

Scientist:

Paul J. Lethaby (Bermuda Institute of Ocean Sciences, BIOS)

Data Manager:

Dominic Smith (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

BCO-DMO Data Manager:

Dana Stuart Gerlach (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Audrey Mickle (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2024-11-01

Restricted:

Validated:

Yes

Current State:

Final with updates expected

Two decibar averaged CTD profiles collected at the Hydrostation S site in the Sargasso Sea from October 1988 (cruise #60643) through December 2023 (cruise #61465)

Abstract:

Data presented here are CTD profiles from the Hydrostation S (or Panulirus) time series site located 20 km SE of Bermuda (32°10’N, 64°30’W) in the Sargasso Sea for October 1988 through December 2023. Profiles include basic CTD measurements of Pressure, Depth, Temperature, and Salinity, reported along with dissolved oxygen, beam attenuation, and relative fluorescence, at two-decibar averages. The profiles were collected during biweekly cruises to the site from October 1988 (cruise #60643) to December 2023 (cruise #61465). Data and samples have been collected using a SeaBird 9/11+ CTD and integrated Niskin rosette system.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2024-11-01	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.860014.8	2024-11-25

Description

Data collection is ongoing, with updates made semi-annually. For guidance on downloading data subsets, please refer to the BCO-DMO ERDDAP instructions here: https://guide.bco-dmo.org/access-and-reuse/erddap. Decadal subsets available for download from this ERDDAP service include the following download links:

Methods & Sampling

CTD profiles at the Hydrostation S site have been collected since station cruise #60643 in October 1988 and although there have been some changes during the past thirty-two years as a result of new instrumentation or methodologies, the the general sampling procedures have been consistent with those detailed in the BATS method manual version #4 (Knap et al., 1997).

In summary, the CTD is operated as per SeaBird's suggested methods with data collection at the full scan rate of 24 Hz. The CTD is powered up and allowed to stabilize at 12 m prior to profiling and once stable (typically 4 minutes) the CTD is brought back to the surface from which point the profile begins with typical descent rates of 0.7-1.0 m/s, depending on weather conditions. Water samples are collected on the upcast and prior to triggering bottles the CTD is kept at the desired depth for a minimum of 60 seconds to ensure that entrainment from the following wake has subsided. Once the water sample is taken the CTD immediately continues with the upcast at an ascent rate of 0.7-1.0 m/s.

The basic system used to acquire CTD data is a Sea-Bird SBE 9plus CTD, with an internal Digiquartz pressure sensor, a Sea-Bird SBE-3F temperature sensor, a Sea-Bird SBE-4 conductivity cell and a Sea-Bird SBE-5 pump. Additional sensors include the Sea-Brid SBE-43 dissolved oxygen sensor, the WET Labs C-Star or Chelsea/Seatech
Transmissometer, the Chelsea Aqua 3 Fluorometer, and the Biospherical/Licor PAR/Irradiance sensor. Present configuration also includes a secondary temperature sensor, a Sea-Bird SBE-35 temperature sensor, a secondary conductivity sensor and pump, which are connected independently from the primary units. The temperature and conductivity sensors are connected by a standard Sea-Bird TC-duct (clear, low viscous type), which ensures that the same parcel of water is sampled by both sensors, improving the accuracy of the computed salinity. The dissolved oxygen sensor is connected downstream from the conductivity cell and the flow rate through this sensor configuration is maintained at a steady rate by the inertia balanced SBE-5 pump.

Ship information:

R/V Weatherbird I (Jan 1983 - September 1989)
R/V Weatherbird II (October 1989 - February 2005)
R/V Atlantic Explorer (May 2006 - Present)

Data Processing Description

CTD data processing typically follows the procedures outlined in Knap et al., 1997 and can be divided into two major stages: (1) CTD signal conversion and dynamic sensor correction, and; (2) static drift corrections and empirical field calibrations. Stage 1 is performed using SeaBird's SEASOFT software and some Matlab scripts, while Stage 2 is performed completely in the Matlab environment.

The basic steps of Stage 1 are:

preliminary CTD sensor quality check;
determination of the dynamic coefficients associated with time alignment and thermal mass problems;
application of pressure filter and velocity filter (0.3 m/s);
application of digital filters for erroneous signal removal;
and finally average to 2 Hz ready for stage 2 processing.

The processing steps in Stage 2 include:

static drift corrections as determined from the sensor calibration history;
empirical field calibration of the conductivity and oxygen sensors;
final QC analysis; and bin average downcast data to 2 dbar.

Following experience of profiling with the SBE–35RT temperature probes, appropriate routines are being implemented to assess performance of the SBE–03f units against the SBE–35 and implement correction procedures. It should be noted that only downcast data are processed and reported, except for the marker data during bottle fires on the upcast.

Instrument calibration:
CTD sensor calibration: Temperature, conductivity and dissolved oxygen sensors are routinely returned to SeaBird every 6-9 months for routine calibration, while the pressure unit is calibrated following full service of the underwater SBE 9 unit every 18-24 months. Auxiliary instruments (fluorometer, tranmissometer, PAR) are sent for calibration every 12 months.

Quality control data access note:
Data fields that have a WHPO quality flag =3 hav been deemed questionable by the PIs, so any individual accessing the data should be aware that they are accessing data of questionable quality. Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data

BCO-DMO Processing

- imported all 805 CTD meta files into BCO DMO system
- concatenated all CTD meta files into one file
- imported all 805 CTD data files into BCO DMO system
- concatenated all CTD data files into one file
- imported all 805 CTD mask files into BCO DMO system
- concatenated all CTD mask files into one file
- replaced NaN and -999 with the fill value 'nd'.
- joined the data and mask files based on row number
- converted date and time to ISO UTC times for deployment and recovery
- converted longitude values to decimal degrees (multiplied degrees West by -1)
- created new fields for "Cruise_type", "Cruise_num", and "Cast" (extracted from ID column)
- modified parameter names to conform with BCO-DMO naming conventions and to be more consistent with other BATS data submissions

Data Files

File
860014_v8_hydrostation_s_ctd.csv (Comma Separated Values (.csv), 283.09 MB) MD5:f4b131f615ac9edf40e62e1dc0e50c09 Primary data file for dataset ID 860014, version 8

Supplemental Files

File

Hydrostation S Data submission V008 update file
filename: hydro_ctd_release_v008_update.txt

(Plain Text, 662 bytes)
MD5:4928807cf1b4c2cc166c10d29a58a0a7

Lists new  cruises since last release and or any modifications for current release V008 from V007.

Summary file for BATS and Hydrostation S version V008 CTD data.
filename: release_v008_summary.txt

(Plain Text, 44.26 KB)
MD5:cc0a6c7a1c6d88aad5eb5938ab814f81

File lists all cruises with cast information for BATS (ID 1####, 2####, 3####), BATS validation (5####) and Hydrostation S ( ID- 6#####) cruises for version 7 (v007)  for October 1988 - December 2023. Note no new BATS validation data for V008.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1633125
NSF Division of Ocean Sciences	OCE-2122606
NSF Division of Ocean Sciences	OCE-1756105

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
Panulirus_site_cruises	Hydrostation S cruises Panulirus cruises	1988-10-26	Multiple Vessels	Nicholas Bates (Principal Investigator) Rodney J. Johnson (Co-Principal Investigator)	data info

Instruments

CTD Sea-Bird 911

Supplied Description:

Instrument Type

Generic Name: CTD Sea-Bird 911

Acronym: CTD SBE 911

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0035/

Generic Description:

The Sea-Bird SBE 911 is a type of CTD instrument package. The SBE 911 includes the SBE 9 Underwater Unit and the SBE 11 Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9 and SBE 11 is called a SBE 911. The SBE 9 uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3 and SBE 4). The SBE 9 CTD can be configured with auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). More information from Sea-Bird Electronics.

CTD Sea-Bird SBE 911plus

Supplied Name: CTD Sea-Bird 911+

Supplied Description:

SeaBird 9/11+ CTD equipped with dual SBE-03f temperature sensors, SBE-04 conductivity sensors, and SBE45 dissolved oxygen sensors

Instrument Type

Generic Name: CTD Sea-Bird SBE 911plus

Acronym: CTD SBE 911plus

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0058/

Generic Description:

The Sea-Bird SBE 911 plus is a type of CTD instrument package for continuous measurement of conductivity, temperature and pressure. The SBE 911 plus includes the SBE 9plus Underwater Unit and the SBE 11plus Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9 plus and SBE 11 plus is called a SBE 911 plus. The SBE 9 plus uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3 plus and SBE 4). The SBE 9 plus CTD can be configured with up to eight auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). more information from Sea-Bird Electronics

Fluorometer

Supplied Name: Chelsea fluorometer

Supplied Description:

Instrument Type

Generic Name: Fluorometer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/113/

Generic Description:

A fluorometer or fluorimeter is a device used to measure parameters of fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. The instrument is designed to measure the amount of stimulated electromagnetic radiation produced by pulses of electromagnetic radiation emitted into a water sample or in situ.

Photosynthetically Available Radiation Sensor

Supplied Name: Biospherical PAR sensor

Supplied Description:

Instrument Type

Generic Name: Photosynthetically Available Radiation Sensor

Acronym: PAR sensor

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/122/

Generic Description:

A PAR sensor measures photosynthetically available (or active) radiation. The sensor measures photon flux density (photons per second per square meter) within the visible wavelength range (typically 400 to 700 nanometers). PAR gives an indication of the total energy available to plants for photosynthesis. This instrument name is used when specific type, make and model are not known.

Sea-Bird SBE 43 Dissolved Oxygen Sensor

Supplied Name: SBE 43 Dissolved Oxygen Sensor

Supplied Description:

Instrument Type

Generic Name: Sea-Bird SBE 43 Dissolved Oxygen Sensor

Acronym: SBE-43 DO

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0036/

Generic Description:

The Sea-Bird SBE 43 dissolved oxygen sensor is a redesign of the Clark polarographic membrane type of dissolved oxygen sensors. more information from Sea-Bird Electronics

Sea-Bird SBE-3 Temperature Sensor

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: Sea-Bird SBE-3 Temperature Sensor

Acronym: SBE-3 Temperature

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/134/

Generic Description:

The SBE-3 is a slow response, frequency output temperature sensor manufactured by Sea-Bird Electronics, Inc. (Bellevue, Washington, USA). It has an initial accuracy of +/- 0.001 degrees Celsius with a stability of +/- 0.002 degrees Celsius per year and measures seawater temperature in the range of -5.0 to +35 degrees Celsius. more information from Sea-Bird Electronics

Sea-Bird SBE-4 Conductivity Sensor

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: Sea-Bird SBE-4 Conductivity Sensor

Acronym: SBE-4 Conductivity

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0417/

Generic Description:

The Sea-Bird SBE-4 conductivity sensor is a modular, self-contained instrument that measures conductivity from 0 to 7 Siemens/meter. The sensors (Version 2; S/N 2000 and higher) have electrically isolated power circuits and optically coupled outputs to eliminate any possibility of noise and corrosion caused by ground loops. The sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Because the outer electrodes are connected together, electric fields are confined inside the cell, making the measured resistance (and instrument calibration) independent of calibration bath size or proximity to protective cages or other objects.

Transmissometer

Supplied Name: Wetlabs transmissometer

Supplied Description:

Instrument Type

Generic Name: Transmissometer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/124/

Generic Description:

A transmissometer measures the beam attenuation coefficient of the lightsource over the instrument's path-length. This instrument designation is used when specific manufacturer, make and model are not known.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
ID	Sample identification; identifies cruise and cast	unitless	sample
ISO_DateTime_UTC_deployed	CTD deployment time in UTC format Format: %Y-%m-%dT%H:%M:%SZ	unitless	ISO_DateTime_UTC
ISO_DateTime_UTC_recovered	CTD recovery time in UTC format Format: %Y-%m-%dT%H:%M:%SZ	unitless	ISO_DateTime_UTC
Latitude_deployed	Latitude of CTD deployment	decimal degrees	lat
Longitude_deployed	Longitude of CTD deployment	decimal degrees	lon
Latitude_recovered	Latitude of CTD recovery	decimal degrees	lat
Longitude_recovered	Longitude of CTD recovery	decimal degrees	lon
Cruise_type	Cruise type (Hydrostation S)	unitless	cruise_type
Cruise_num	BATS Cruise number	unitless	cruise_id
Cast	Cast Number (1-80 = CTD, 81-99 = Hydrocast)	unitless	cast
Depth	Collection depth of sample	meters (m)	depth
QF_Depth	Quality control flag for depth; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
Pressure	Pressure (dbar)	decibars (dbar)	press
QF_Pressure	Quality control flag for pressure; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
Temperature	Temperature (ITS-90)	degrees Celsius	temp
QF_Temperature	Quality control flag for temperature; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
Salinity	Salinity (psu)	PSU	sal_ctd
QF_Salinity	Quality control flag for salinity; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
Oxygen	Dissolved Oxygen	micromole per kilogram (umol/kg)	O2
QF_Oxygen	Quality control flag for dissolved oxygen; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
BAC	Beam Attenuation Coefficient	reciprocal meters (1/m)	beam_cp
QF_BAC	Quality control flag for BAC; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
Flu	Fluorescence	relative fluorescence units (RFU)	fluor
QF_Flu	Quality control flag for fluorescence; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
PAR	Photosynthetically Active Radiation (PAR)	microeinsteins per meter squared per second (uE/m2/s)	PAR
QF_PAR	Quality control flag for PAR; Parameter quality flags defined as 1= unverified, 2= verified acceptable, 3= questionable, 4= bad, 9= no data	unitless	q_flag
Date_deployed	CTD deployment date in YYYYMMDD format	unitless	date
Date_recovered	CTD recovery date in YYYYMMDD format	unitless	date
Time_deployed	CTD deployment time in HHMM format	unitless	time
Time_recovered	CTD recovery time in HHMM format	unitless	time
Decimal_Year_deployed	CTD deployment time in decimal year format	unitless	year_decimal
Decimal_Year_recovered	CTD recovery time in decimal year format	unitless	year_decimal