Dataset: HADES-K Nereus dives - bottom navigation
Deployment: TN309

HADES-K - Nereus bottom navigation

View Data: For data, See Dataset Metadata Page: https://osprey.bco-dmo.org/dataset/764727

Principal Investigator:

Timothy M. Shank (Woods Hole Oceanographic Institution, WHOI)

Co-Principal Investigator:

Jeffrey C. Drazen (University of Hawaiʻi at Mānoa, SOEST)

Paul Yancey (Whitman College)

BCO-DMO Data Manager:

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

Project:

Controls on Hadal Megafaunal Community Structure: a Systematic Examination of Pressure, Food Supply, and Topography (HADES)

Version:

Deployment Synonyms:

HADES-K, HADESK

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Description

This dataset includes HROV/Nereus dive bottom navigation in the Kermadec Trench calculated from course, speed and distance from origin, April/May 2014. The dives were in the Southwest Pacific, 4000 to ~10,000m from the RV/ Thomas G. Thompson during cruise TN309 (HADES-K), April - May 2014.

Methods & Sampling

Dataset acquisition description

The HROV Nereus was used to conduct exploration and characterization (including downloading video seafloor transects) of the Kermadec Trench region in May 2014. Geo-referenced vehicle navigation was conducted using the R/V Thompson’s GPS launch position of the vehicle, the estimated initial on bottom position of the vehicle, the course over ground (determined by the Gyro heading, Doppler Velocity Profiler, and thruster speed).

Navigation processing was conducted Matlab (2011 Release; MathWorks, Inc.) and Microsoft Excel for Mac 14.7.3.

Summary of HADES-K Nereus dives:

Nereus Dive #	Date	Mission Depth (m)	Dive Duration (hrs:min)	# of Transects	Bottom Duration (hrs:min)
64	4/14/2014	4000	12:00	1	6:41
72	5/2/2014	6060	17:19	4	9:28
73	5/4/2014	7000	18:04	2	8:09
74	5/5/2014	8100	19:57	1	10:07
75	5/8/2014	9000	13:44	0	2:16
76	5/10/2014	10,000	11:54	2	6:28

Data Processing Description

Dataset Processing Description

BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- re-formatted date from m/d/yyyy to yyyy-mm-dd
- concatenated all the dive data into a single file
- added column for temp and altitude if not present in dive file
- reduced lat and lon digits from 7 to 5 to right of the decimal
- added date_start, obtained from PI submission, differs somewhat from HadesK_deploylog dataset

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1131620	NSF Division of Ocean Sciences

Instruments

Acoustic Doppler Velocimeter

Supplied Name: Doppler Velocity Profiler

Supplied Description:

Instrument Type

Generic Name: Acoustic Doppler Velocimeter

Acronym: ADV

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/384/

Generic Description:

ADV is the acronym for acoustic doppler velocimeter. The ADV is a remote-sensing, three-dimensional velocity sensor. Its operation is based on the Doppler shift effect. The sensor can be deployed either as a moored instrument or attached to a still structure near the seabed.

Reference:
G. Voulgaris and J. H. Trowbridge, 1998. Evaluation of the Acoustic Doppler Velocimeter (ADV) for Turbulence Measurements. J. Atmos. Oceanic Technol., 15, 272–289. doi: http://dx.doi.org/10.1175/1520-0426(1998)015<0272:EOTADV>2.0.CO;2

Gyro

Supplied Name: Vehicle Gyro

Supplied Description:

Instrument Type

Generic Name: Gyro

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0079/

Generic Description:

Compass with a motorized gyroscope that tracks true north (heading).

HROV Nereus

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: HROV Nereus

Generic Description:

Nereus is an efficient, multi-purpose “hybrid” vehicle that can explore and operate in the crushing pressures of the greatest ocean depths. An unmanned vehicle, Nereus operates in two complementary modes. It can swim freely as an autonomous underwater vehicle (AUV) to survey large areas of the depths, map the seafloor, and give scientists a broad overview. When Nereus locates something interesting, the vehicle’s support team can bring the vehicle back on board the ship and transforms it into a remotely operated vehicle (ROV) tethered to the ship via a micro-thin, fiber-optic cable. Through this tether, Nereus can transmit high-quality, real-time video images and receive commands from skilled pilots on the ship to collect samples or conduct experiments with a manipulator arm.

Technical specifications:

Weight on land: 2,800 kg
Payload capacity: 25 kg
Maximum speed: 3 knots
Batteries: rechargable lithium ion, 15 kilowatt hours in two pressure housings
Thrusters: 2 fore and aft, 2 vertical, 1 lateral (ROV mode) 2 fore and aft, 1 vertical (AUV mode)
Lights: variable output LED array, strobes
Manipulator arm: Kraft TeleRobotics 7-function hydraulic manipulator
Sonar: scanning sonar, forward look and profile, 675 KHz
Sensors: magnetometer, CTD (to measure conductivity, temperature, and depth)

Nereus supports a variety of science operations: Push coring, measuring heat flow, geotechnical and geochemical sensing, rock sampling and drilling, biological sampling, water sampling, high resolution acoustic bathymetry, and optical still and video imagery.

More information is available from the operator site at URL.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
Dive	Nereus dive identifier	unitless	dive_id
Date_start	UTC date at start of dive formatted as yyyymmdd	unitless	date
Time2_GMT	UTC time formatted as HH:MM:SS	unitless	time_utc
COS	Course Over Ground	degrees	cog
SOG	Speed Over Ground	meters per second	sog
Depth	pressure depth	meters	depth
Heading	Compass vector degrees of the vehicle	degrees	heading
Altitude	Doppler Velocity Log (2 beams)	meters	altitude
temp	Temperature	degrees Celsius	temp
Distance	Distance traveled calculated using COS, SOG, and Heading	meters	no_bcodmo_term
Latitude	seafloor latitude position calculated from course, speed and distance from origin.	decimal degrees	lat
Longitude	seafloor longitude position calculated from course, speed and distance from origin.	decimal degrees	lon

Database

Contribute Data

Dataset: HADES-K Nereus dives - bottom navigation
Deployment: TN309

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: HADES-K Nereus dives - bottom navigationDeployment: TN309

Dataset acquisition description

Dataset Processing Description

Dataset: HADES-K Nereus dives - bottom navigation
Deployment: TN309