Dataset: LB_2012_Ship_CTD-Optics-O2

Name: Vertical CTD profiles, bin-averaged, and downcast from the R/V Savannah cruises in the South Atlantic Bight (SAB) continental shelf off Long Bay (-79W, 32N; -77W, 34 N) (Long Bay Wintertime Bloom project)
Published: 2015-03-30
Keywords: oceans

Cite This Dataset

Spatial Extent: N:33.380503 E:-77.240147 S:32.48273 W:-78.748143

Project:

Mechanisms of nutrient input at the shelf margin supporting persistent winter phytoplankton blooms downstream of the Charleston Bump (Long Bay Wintertime Bloom)

Principal Investigator:

James Nelson (Skidaway Institute of Oceanography, SkIO)

Co-Principal Investigator:

Catherine Edwards (Skidaway Institute of Oceanography, SkIO)

Harvey E. Seim (University of North Carolina at Chapel Hill, UNC-Chapel Hill)

Contact:

Julie Amft (Skidaway Institute of Oceanography, SkIO)

BCO-DMO Data Manager:

Nancy Copley (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

2015-03-30

Version Date:

2015-03-30

Validated:

Current State:

Final with updates expected

Vertical CTD profiles, bin-averaged, and downcast from the R/V Savannah cruises in the South Atlantic Bight (SAB) continental shelf off Long Bay (-79W, 32N; -77W, 34 N) (Long Bay Wintertime Bloom project)

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Description

CTD casts were conducted in Long Bay, South Atlantic Bight, SE United States from the middle continental shelf (~ 30 m depth) to upper slope (~260 m depth). The primary cross-shelf CTD survey line was off Myrtle Beach, SC between 33.17/-78.33 and 32.76/-77.91. On cruise SAV12-03, CTD profiles were also conducted at stations on parallel cross-shelf lines ~26 km to the SW and NE of the central line.

NOT FINAL - awaiting further calibration.

Methods & Sampling

Instrument configuration of the R/V Savannah CTD/carousel water sampler:
Sea-Bird SBE 25 Sealogger CTD; Sea-Bird SBE 33 deck box; Sea-Bird SBE 32C carousel pylon; Sea-Bird SBE 43 oxygen sensor; WET Labs ECO chlorophyll fluorometer; WET Labs ECO CDOM fluorometer; WET Labs ECO BB optical backscatter sensor; LI-COR 193SA PAR sensor; Sea-Bird SBE 5P pump. The carousel was equipped with eight 8-L external-closure water sampling bottles (Ocean Test Equipment Model 110).

The instrument inventory for the ship’s CTD system (including spares for all components) was managed by the ship’s Marine Technician (John Bichy). Instrument calibrations were performed by manufacturers within suggested intervals. Calibration factors and calibration dates are listed in the file “ctd_con_report.txt” that accompanies the cast data files. The sampling rate for the CTD system was set at 1 Hz.

The deployment procedure included a near-surface “soak” (at least one minute) prior to profiling to allow air to be purged from tubing lines and sensors to equilibrate. The package was then lowered (descent rate of ~0.3-0.4 m/s) to a target depth, typically about 2 m above the seafloor. If desired, water samples were collected during the upcast using the carousel water sampling system. Water sample depths were selected based on the real-time profiles obtained during the downcast.

Methods Reference:

Fofonoff, N.P. and R.C. Millard, Jr, 1983. Algorithms for computation of fundamental properties of seawater. UNESCO Technical Papers in Marine Science #44.

Data Processing Description

Initial CTD data processing used the Sea-Bird data processing software package with input of the raw data file (*.hex) and associated configuration file (*.con) for each cast. Processing steps are described in the file “ctd_process.txt” that accompanies the data files. For bin-averaging, scans acquired during the initial surface “soak” period prior to profiling were removed and only the downcast was processed using 1-m bins for station depths < 100 m and 2-m bins for station depths > 100 m. The bin-averaged data was output in ASCII file format (*b.cnv). Parameter names and units for the output data files are listed above (by column).

Factory calibration factors for CTD package sensors were applied to calculate conductivity, pressure, and temperature (see “ctd_con_report.txt”). Depth was calculated from pressure using the “seawater” setting in the Sea-Bird software and density was calculated by the EOS80 equation of state for seawater (Fofonoff and Millard, 1983). Oxygen (kg/m3, % saturation), optical backscatter (1/m) and PAR (as quantum scalar irradiance, micro-mole photons / m2 s1) were calculated using the manufacturer-supplied calibration factors and algorithms included in the Sea-Bird data processing package. Chlorophyll fluorescence and CDOM fluorescence are reported here as the raw voltages (0-5 volts total signal range).

BCO-DMO Processing:

- added conventional header with dataset name, PI name, version date, reference information, replacing ctd header
- renamed some parameters to BCO-DMO standard
- created toplevel file
- added ctd metadata columns to cast data: cruise_id, cast, year, mon, day_gmt, time_gmt, lat_deg, lat_min, lon_deg, lon_min, depth, station, comment

Data Files

File
ship_CTD.csv (Comma Separated Values (.csv), 1.43 MB) MD5:40c5c5cdbe352caca2d60f4a3b83043c Primary data file for dataset ID 554711

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1032276
NSF Division of Ocean Sciences	OCE-1032285

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
SAV-12-02	LB 2012 Deployment Cruise	2012-01-18	R/V Savannah	James Nelson (Chief Scientist) Catherine Edwards (Co-Chief Scientist)	data info
SAV-12-03	LB 2012 Leg 1 Cruise	2012-01-24	R/V Savannah	James Nelson (Chief Scientist) Catherine Edwards (Co-Chief Scientist)	data info
SAV-12-05	LB 2012 Leg 2 Cruise	2012-02-13	R/V Savannah	James Nelson (Chief Scientist) Catherine Edwards (Co-Chief Scientist)	data info
SAV-12-11	LB 2012 Leg 3 Cruise	2012-03-13	R/V Savannah	James Nelson (Chief Scientist) Catherine Edwards (Co-Chief Scientist)	data info
SAV-12-14	LB 2012 Recovery Cruise	2012-04-02	R/V Savannah	James Nelson (Chief Scientist) Catherine Edwards (Co-Chief Scientist)	data info

Instruments

CTD - profiler

Supplied Name: CTD

Supplied Description:

Sea-Bird SBE 25 Sealogger CTD; Sea-Bird SBE 33 deck box; Sea-Bird SBE 32C carousel pylon; Sea-Bird SBE 43 oxygen sensor; WET Labs ECO chlorophyll fluorometer; WET Labs ECO CDOM fluorometer; WET Labs ECO BB optical backscatter sensor; LI-COR 193SA PAR sensor; Sea-Bird SBE 5P pump. The carousel was equipped with eight 8-L external-closure water sampling bottles (Ocean Test Equipment Model 110).

Instrument Type

Generic Name: CTD - profiler

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/130/

Generic Description:

The Conductivity, Temperature, Depth (CTD) unit is an integrated instrument package designed to measure the conductivity, temperature, and pressure (depth) of the water column. The instrument is lowered via cable through the water column. It permits scientists to observe the physical properties in real-time via a conducting cable, which is typically connected to a CTD to a deck unit and computer on a ship. The CTD is often configured with additional optional sensors including fluorometers, transmissometers and/or radiometers. It is often combined with a Rosette of water sampling bottles (e.g. Niskin, GO-FLO) for collecting discrete water samples during the cast.

This term applies to profiling CTDs. For fixed CTDs, see https://www.bco-dmo.org/instrument/869934.

CTD-fluorometer

Supplied Description:

WET Labs ECO chlorophyll fluorometer; WET Labs ECO CDOM fluorometer

Instrument Type

Generic Name: CTD-fluorometer

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

Generic Description:

A CTD-fluorometer is an instrument package designed to measure hydrographic information (pressure, temperature and conductivity) and chlorophyll fluorescence.

LI-COR LI-193 PAR Sensor

Supplied Name: LI-COR LI-193SA PAR sensor

Supplied Description:

Instrument Type

Generic Name: LI-COR LI-193 PAR Sensor

Acronym: LI-COR LI-193 PAR

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0458/

Generic Description:

The LI-193 Underwater Spherical Quantum Sensor uses a Silicon Photodiode and glass filters encased in a waterproof housing to measure PAR (in the 400 to 700 nm waveband) in aquatic environments. Typical output is in micromol s-1 m-2. The LI-193 Sensor gives an added dimension to underwater PAR measurements as it measures photon flux from all directions. This measurement is referred to as Photosynthetic Photon Flux Fluence Rate (PPFFR) or Quantum Scalar Irradiance. This is important, for example, when studying phytoplankton, which utilize radiation from all directions for photosynthesis. LI-COR began producing Spherical Quantum Sensors in 1979; serial numbers for the LI-193 begin with SPQA-XXXXX (licor.com).

Sea-Bird SBE 25 Sealogger CTD

Supplied Name: CTD SBE 25

Supplied Description:

Sea-Bird SBE 25 Sealogger CTD

Instrument Type

Generic Name: Sea-Bird SBE 25 Sealogger CTD

Acronym: CTD SBE 25

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0040/

Generic Description:

The Sea-Bird SBE 25 SEALOGGER CTD is battery powered and is typically used to record data in memory, eliminating the need for a large vessel, electrical sea cable, and on-board computer. All SBE 25s can also operate in real-time, transmitting data via an opto-isolated RS-232 serial port. Temperature and conductivity are measured by the SBE 3F Temperature sensor and SBE 4 Conductivity sensor (same as those used on the premium SBE 9plus CTD). The SBE 25 also includes the SBE 5P (plastic) or 5T (titanium) Submersible Pump and TC Duct. The pump-controlled, TC-ducted flow configuration significantly reduces salinity spiking caused by ship heave, and in calm waters allows slower descent rates for improved resolution of water column features. Pressure is measured by the modular SBE 29 Temperature Compensated Strain-Gauge Pressure sensor (available in eight depth ranges to suit the operating depth requirement). The SBE 25's modular design makes it easy to configure in the field for a wide range of auxiliary sensors, including optional dissolved oxygen (SBE 43), pH (SBE 18 or SBE 27), fluorescence, transmissivity, PAR, and optical backscatter sensors. More information from Sea-Bird Electronics: http:www.seabird.com.

Sea-Bird SBE 33 Carousel Deck Unit

Supplied Name: SBE 33

Supplied Description:

Instrument Type

Generic Name: Sea-Bird SBE 33 Carousel Deck Unit

Acronym: SBE 33

Generic Description:

The rack-mountable SBE 33 provides power and real-time data acquisition and control for an SBE 32 Carousel Water Sampler that has the SBE 33 interface option installed in its pylon. The SBE 33 is compatible with all Carousel sizes - full size, compact, and sub-compact. When powered and controlled by the SBE 33, the Carousel can be used:

- with an SBE 19, 19plus, 19plus V2, 25, 25plus, or 49 CTD
- without a CTD
- with a Neil Brown Mk III CTD (requires optional interface for both SBE 32 and 33)

The SBE 33 can also provide power and real-time data acquisition and control for the smaller SBE 55 ECO Water Sampler used with an SBE 19, 19plus, 19plus V2, 25, 25plus, or 49 CTD, or no CTD.

See http://www.seabird.com/sbe33-deck-unit for further details.

Sea-Bird SBE 43 Dissolved Oxygen Sensor

Supplied Name: SBE-43 DO

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

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	cruise identification	unitless	cruise_id
year	year	yyyy	year
cast	cast	integer	cast
month_gmt	GMT month	mm	month_gmt
day_gmt	GMT day of month	dd	day_gmt
time_gmt	GMT time of day; 24 hour clock	HH:MM:SS	time_gmt
yrday_gmt	GMT day and decimal time: e.g. 326.5 for the 326th day of the year or November 22 at 1200 hours (noon)	unitless	yrday_utc
ISO_DateTime_UTC	Date/Time (UTC) ISO formatted	yyyy-mm-ddTHH:MM:SS[.xx]Z	ISO_DateTime_UTC
lat	latitude; north is positive	decimal degrees	lat
lon	longitude; east is positive	decimal degrees	lon
depth_max	maximum depth of cast	meters	depth_max
station	station: LB# = Middle Transect LBS# = South Transect LBN# = North Transect # = distance counter (km) starting with +00 inshore and increasing offshore	unitless	station
comment	comments	unitless	comment
depth	depth	meters	depth
temp	temperature	degrees Celsius	temp
cond	conductivity	Siemens/meter	cond
sal	salinity	PSU	sal
density	seawater density	kilograms/meter^3	density
flvolt	voltage 0: chlorophyll fluorometer; raw output	volts	flvolt
CDOM_v	voltage 1: CDOM fluorometer; raw output	volts	CDOM_v
light_bs	voltage 2: optical backscatter meter; raw output	volts	light_bs
backscatter	WETLabs backscatter; factory calibration	per meter	beam_cp
O2_sat	oxygen saturation	percent	O2_sat_pcnt
O2	dissolved oxygen concentration	umol/Kg	O2
par	PAR/Quantum Scalar Irradiance	umol photons/m^2 s^1	PAR
flag	quality flag: 0.000e+00 is ok	unitless	flag

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Dataset: LB_2012_Ship_CTD-Optics-O2