Dataset: Seaglider observations at Station ALOHA in the North Pacific Subtropical Gyre
Deployment: Karl_Station_Aloha_Hawaii_Ms_Mahi

View Data: For data, See Dataset Metadata Page: https://www.bco-dmo.org/dataset/928732

Principal Investigator:

Sara Ferrón (University of Hawaiʻi at Mānoa)

David M. Karl (University of Hawaiʻi at Mānoa)

Co-Principal Investigator:

Benedetto Barone (University of Hawaiʻi at Mānoa)

Scientist:

Catherine Garcia (University of Hawaiʻi at Mānoa)

Technician:

Steve Poulos (University of Hawaiʻi at Mānoa)

BCO-DMO Data Manager:

Lynne M. Merchant (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Oligotrophic ocean metabolism from underwater glider observations (Glider Ocean Metabolism)

Version:

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Description

This BCO-DMO dataset page contains supporting metadata and CSV formatted datasets for seaglider deployments from 2008 to 2023. Additional NetCDF formatted datasets, containing parameters in the CSV formatted datasets along with raw data and QC values, for seaglider deployments from 2008 to 2023 are available at Zenodo, DOI: 10.5281/zenodo.10416616. See the “Related Datasets” section.

All the seaglider deployments dataset files have the same parameters which are defined on this dataset page. Individual seaglider deployments did not measure all of the parameters, though, e.g. either bbp650 or bbp660, and in that case, values are left blank for unmeasured parameters.

Parameters in common with the NetCDF formatted datasets and the CSV formatted datasets are: ISO_DateTime_UTC, lat, lon, depth, divenum, direction, temp, cond, salin, sigma, oxygen, chla, bbp470, bbp470_spikeflag, bbp650, bbp650_spikeflag, bbp660, bbp660_spikeflag, bbp700, and bbp700_spikeflag.

Parameters specific to the CSV formatted datasets are: seaglider_deployment, seaglider_platform, and seaglider_mission.

Additional parameters included in the NetCDF files are pressure, pitch, raw data, chla_spikeflag, and QC flags: press, pitch, oxygen_raw, chla_raw, chla_spikeflag, bbp470_raw, bbp650_raw, bbp660_raw, bbp700_raw, temp_qcflag, cond_qcflag, salin_qcflag, sigma_qcflag, oxygen_qcflag, chla_qcflag, bbp470_qcflag, bbp650_qcflag, bbp660_qcflag, and bbp700_qcflag

The supplemental file seaglider_deployments_metadata.csv contains the locations and dates of each seaglider deployment and recovery via ships and small boats along with the locations and dates of data collection for each seaglider deployment. Additional metadata columns with flags of True or False were included to indicate if the following parameters are measured in an individual deployment dataset: oxygen, bbp650, bbp660, and bbp700. These flag columns were added because deployments either measured bbp650 or bbp660, and oxygen and bbp700 are not always measured during a deployment. All the seaglider deployments dataset files have the same parameters to enable datasets to be more easily queried and combined programmatically.

Methods & Sampling

Dataset acquisition description

Vertically resolved data were collected by underwater Seagliders, which are guided autonomous underwater vehicles developed at the University of Washington’s Applied Physics lab (Eriksen et al., 2001). The Seagliders were piloted either in a circular or 'bowtie' pattern for several months in each mission around Station ALOHA.

Gliders were equipped with the sensors to measure temperature and salinity (Seabird CT Sail), pressure (Paine Electronics 211-75-710-05 and Kistler 4260M00), dissolved oxygen (Aandera models 5013 and 4330), chlorophyll fluorescence and optical backscatter at three wavelengths: 470 nm, 700 nm, and either 650 or 660 nm (WET Labs ECO Triplet ).

Data Processing Description

Dataset Processing Description

The raw observations were quality-controlled, accounting for known sensor responses and deviations from factory calibrations. Detailed descriptions of the data processing, quality control metrics, and calibration methods are provided by Garcia et al. (2023; https://doi.org/10.5281/zenodo.10416616). Quality control steps included a pitch angle test (to detect density inversions), global and regional range tests, stuck value test, biofouling evidence test, and visual inspection. If a test passed, the data were assigned a QC value of 1 (‘good data’). If a test failed (e.g. out of range or density inversion tests), data were flagged, either as ‘questionable data’ (QC = 3) or as ‘bad data’ (QC = 4). All quality control flags and adjustments (i.e. calibration and correction parameters) are preserved in each mission’s file. Code for all processing steps is available on GitHub: https://github.com/cathygarcia/SeagliderDataprocessing.

Data processing steps for each variable are summarized below:

Temperature, Conductivity, Salinity, and Potential Density Anomaly

Both temperature and conductivity profiles were lag corrected.
Practical salinity was calculated using the Gibbs Seawater Toolbox (McDougall et al., 2011), (gsw_SP_from_C.m), and then converted to absolute salinity (gsw_SA_from_SP.m).
Potential density anomaly was calculated with respect to a reference water pressure of 0 db using the Gibbs Seawater Toolbox (gsw_sigma0.m).

Dissolved oxygen concentrations

Raw optode phase values proceeded through a series of corrections to account for the effects of temperature, salinity, pressure, and time response in addition to sensor drift (Bittig et al., 2018, Barone et al., 2019).
Optode phase values were converted to dissolved oxygen concentrations, and re-calibrated using discrete Winkler measurements.

Chlorophyll a

Factory-calibrated chlorophyll a observations were re-calibrated using discrete measurements of either HPLC chlorophyll a (16 missions) or fluorometric chlorophyll a (2 missions).
Daytime chlorophyll a values are not quench corrected, and may be lower than actual values. It is recommended to use nighttime profiles near the surface.
Additionally, a spike flag is included based on published protocol (Briggs et al., 2011).

Backscattering coefficient due to particles (bbp)

Factory-calibrated bbp values could have a large offset, that was not expected based on natural variability.
A mission-specific deep dark correction (1st percentile of bbp at 190-200 m) was subtracted for each bbp dataset. Both the uncorrected and corrected data are available.
Additionally, a spike flag is included based on published protocol (Briggs et al., 2011).

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-2048435	NSF Division of Ocean Sciences

Instruments

Aanderaa Oxygen Optodes

Supplied Name: Aandera oxygen optode models 5013 and 4330

Supplied Description:

Instrument Type

Generic Name: Aanderaa Oxygen Optodes

Acronym: AOO

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/351/

Generic Description:

Aanderaa Oxygen Optodes are instrument for monitoring oxygen in the environment. For instrument information see the Aanderaa Oxygen Optodes Product Brochure.

CTD Sea-Bird 41

Supplied Name: Seabird CT Sail

Supplied Description:

Instrument Type

Generic Name: CTD Sea-Bird 41

Acronym: CTD SBE 41

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

Generic Description:

The Sea-Bird SBE 41 CTD module was originally developed in 1997 for integration with sub-surface oceanographic floats. It uses MicroCAT Temperature, Conductivity, and Pressure sensors.

Pressure Sensor

Supplied Name: Paine Electronics Pressure Transducer series 211-75-710, part number 211-75-710-05

Supplied Description:

Instrument Type

Generic Name: Pressure Sensor

Generic Description:

A pressure sensor is a device used to measure absolute, differential, or gauge pressures. It is used only when detailed instrument documentation is not available.

Pressure Sensor

Supplied Name: Kistler Piezoresistive Pressure Sensor 4260M00

Supplied Description:

Instrument Type

Generic Name: Pressure Sensor

Generic Description:

A pressure sensor is a device used to measure absolute, differential, or gauge pressures. It is used only when detailed instrument documentation is not available.

Seaglider

Supplied Description:

Instrument Type

Generic Name: Seaglider

Generic Description:

The Seaglider is an autonomous underwater vehicle developed through a collaboration between The Applied Physics Laboratory -University of Washington and the University of Washington School of Oceanography. These small, free-swimming vehicles can gather conductivity-temperature-depth (CTD) data from the ocean for months at a time and transmit it to shore in near-real time via satellite data telemetry. Seagliders make oceanographic measurements traditionally collected by research vessels or moored instruments. They can survey along a transect, profile at a fixed location, and can be commanded to alter their sampling strategies throughout a mission.

Wet Labs ECO Triplet

Supplied Name: WET Labs ECO Triplet

Supplied Description:

Instrument Type

Generic Name: Wet Labs ECO Triplet

Acronym: Triplet

Generic Description:

The Wet Labs ECO Triplet is a special-order, three-optical-sensor instrument available from WET Labs (wetlabs.com) in a user-defined configuration. The Triplet addresses the need for multiple simultaneous scattering and fluorescence sensors for autonomous vehicles and unattended measurement platforms. For example, possible configurations include any combination of three of the following: Blue scattering, Green scattering, Red scattering, Chlorophyll fluorescence, CDOM fluorescence, Phycoerythrin fluorescence, Phycocyanin fluorescence, Rhodamine fluorescence, or Uranine (fluorescein) fluorescence.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
seaglider_deployment	Seaglider deployment	unitless	deployno
seaglider_platform	Seaglider platform	unitless	platform
seaglider_mission	Seaglider mission	unitless	no_bcodmo_term
ISO_DateTime_UTC	Date and time (UTC) in ISO8601 format	unitless	ISO_DateTime_UTC
lat	latitude, South is negative	decimal degrees	lat
lon	longitude, West is negative	decimal degrees	lon
depth	Depth	meters (m)	depth
divenum	Dive number	unitless	dive_id
direction	Profile direction (down or up)	unitless	no_bcodmo_term
temp	Temperature	degrees Celsius	temp
cond	Conductivity	millisiemens/centimeter (mS cm-1)	cond
salin	Absolute Salinity	gram/kilogram (g/kg)	sal
sigma	Potential Density Anomaly wrt 0 db	kilogram/cubic meter (kg/m^3)	no_bcodmo_term
oxygen	Dissolved oxygen concentration	micromole/Liter (umol/L)	O2
chla	Chlorophyll a concentration	miligram/cubic meter (mg/m^3)	chl_a
bbp470	Particle Backscattering Coefficient (470 nm)	reciprocal meter (m^-1)	bbp470
bbp470_spikeflag	Particle Backscattering Coefficient (470 nm) spike flag ( 0= no spikes and 1 = spikes)	unitless	flag
bbp650	Particle Backscattering Coefficient (650 nm)	reciprocal meter (m^-1)	bbp650
bbp650_spikeflag	Particle Backscattering Coefficient (650 nm) spike flag ( 0= no spikes and 1 = spikes)	unitless	flag
bbp660	Particle Backscattering Coefficient (660 nm)	reciprocal meter (m^-1)	bbp660
bbp660_spikeflag	Particle Backscattering Coefficient (660 nm) spike flag ( 0= no spikes and 1 = spikes)	unitless	flag
bbp700	Particle Backscattering Coefficient (700 nm)	reciprocal meter (m^-1)	bbp700
bbp700_spikeflag	Particle Backscattering Coefficient (700 nm) spike flag ( 0= no spikes and 1 = spikes)	unitless	flag

Database

Contribute Data

Dataset: Seaglider observations at Station ALOHA in the North Pacific Subtropical Gyre
Deployment: Karl_Station_Aloha_Hawaii_Ms_Mahi

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Seaglider observations at Station ALOHA in the North Pacific Subtropical GyreDeployment: Karl_Station_Aloha_Hawaii_Ms_Mahi

Dataset acquisition description

Dataset Processing Description

Dataset: Seaglider observations at Station ALOHA in the North Pacific Subtropical Gyre
Deployment: Karl_Station_Aloha_Hawaii_Ms_Mahi