The SCS data files logging the raw data are set to break once a day at GMT midnight to make acquisition, plotting, processing and transfer easier.

The following information is quoted from SOI's "Guide to SCS Data Sensors and Formats SCS v 4.6.0", by MT Colleen Peters, 2013. There is additional information available in this document that may be relevant to users of these data.

The CNAV (a dynamic Digital Global Navigation Satellite System (DGNSS) precise point positioning systemby C & C Technologies) is the primary scientific navigation positioning system, with capabilities of a decimeter or better. The CNAV provides the Seapath320 with RTCM messages to give improved accuracy. The Seapath 320 position and attitude data are utilized by the multibeam sonars. The CNAV display is located in the rack room. The antenna is located on the starboard side of upper main mast.

Kongsberg Seatex Seapath 320: The Seapath Motion Reference Unit (MRU) is located in a cubby on the starboard side of the passageway between the mess and the forward stairs on the 2^nd deck (just before the watertight door). The antennas are on the port and starboard side of the main mast. The deck unit and Human Interface are in 322 rack 1. Seapath provides position and attitude data to all of the sonar systems. It is also connected to the CTD computer for use with the XBT and CTD. The position and attitude data are also distributed to other systems via an overland splitter.

Raytheon Anschuetz STD 22 Gyrocompass: The gyrocompass feed goes both to the bridge and to NMEA splitters. The data is then broadcast via a network patch panel. The gyro data is also fed into the multibeam systems.

Vaisala WXT520: The weather data comes from a sensor mounted on the upper level of the main mast. The Vaisala WXT520 collects wind direction and speed as well as air temperature, relative humidity and pressure. The sensor is directly connected to the bridge Helideck Monitoring System (HMS). The data are then output from the HMS 100 to the network and brought into SCS.

Lambrecht QUATRO IND-H’: The second sensor, the Lambrecht QUATRO IND-H’ measures wind speed and direction, as well as pressure, air temperature and relative humidity. The met data is only connected to the bridge display on the navigation station. The wind data are then output to the bridge’s Raytheon navigation system and sent through the network in the BridgeData string. This sensor is for navigation only, and does not get calibrated.

Biospherical Surface Photosynthetically Active Radiation (PAR) Sensor : A PAR sensor with a spherical receiver that is equally sensitive to photons from all direction measures Quantum Scalar Irradiance (QSI). An alternative term for this quantity is "Photosynthetic Photon Flux Fluence Rate" (PPFFR). QSI or PPFFR are defined as the integral photon flux of photons in the 400–700 nm wavelength interval at a point in space from all directions around the point.

Scientific Seawater System: This system was designed to run a continuous flow of seawater through several instruments to measure the properties of the surface water. The intake for this system in is the bow, and the equipment (pump, plumbing and external temperature probe) are all located forward of the bow-thruster room.

Generally, all sensors are turned on as soon as the ship is in clear water when leaving port and run for the duration of the cruise. Running the system in an environment prone to chemicals from ships and land facilities can damage the sensitive sensors. Sometimes, when the ship is in rough weather, the seawater system may catch an air bubble, which can disrupt the data, or require the system to be shut down temporarily. These occasions can be easy to identify by plotting the two temperature measurements—if the TSG temperature is high (like 5°C difference) then there is likely no flow in the system, which allows the TSG temperature to increase to room temperature, while the remote probe will stay at ocean temperature. This will vary with the local ocean temperatures.

SBE 38 Remote Temperature Probe: The ‘external’ or remote probe, SBE 38 measures temperature as close to the system’s intake as possible. When we send ‘sea surface temperature’ data, we primarily use this sensor. This temperature is used to calculate sound velocity with the TSG.

SBE 45 Micro Thermosalinograph (TSG): The TSG measures temperature and conductivity. With these two measurements, it calculates salinity. With the salinity from the TSG, and the temperature from the remote probe, it calculates sound velocity. Using the remote probe makes sound velocity calculations more accurate because the temperature at the TSG can be affected slightly as it travels through the ship to the wet lab.

Valeport MiniSVS Sound Velocity Probe: The Sound Velocity Probe (SVP) is accessed in the forward deck store, by the aft bulkhead behind the workbench. It sits in a pipe welded to the ship’s structure. Strapped into a weighted jacket, it is lowered with a cable (not the data cable) and the probe face sticks out past the hull to measure sound velocity close to the transducers. The probe can then be pulled out of the tube for inspection and cleaning, even while the ship is underway. This sensor is calibrated annually.

Seabird 9/11 plus Conductivity Temperature and Depth (CTD): CTDs are standard oceanographic systems on most ocean-going research vessels. This system provides a profile of the water column, measuring the chemical and physical properties of the water.

The CTD data is logged using the Seabird Seasave software, and also logged in SCS as a backup. It is helpful to view the CTD depth on a real time plot with winch wire out. It is also useful for comparing sea-surface temperature between the SBE 38and SBE 9plus. The CTD is a 6800m rated sensor with dual temperature and conductivity sensors. It can accommodate up to 8 auxiliary sensors. We currently have 2 SBE 43 dissolved oxygen, a WetLabs ECO FLNTU fluorometer/turbidity sensor and a C-Star Transmissometer. Due to the nature of CTD casts, the auxiliary instruments can change frequently within a cruise or between cruises, so the data are not accommodated in SCS. It would require frequent reprogramming, which would interrupt the bulk of the data being logged on SCS. The primary sensors are therefore the only ones logged by SCS. These include pressure, depth, conductivity, temperature, salinity and sound velocity.

The CTD frame and SBE 32 carousel can accommodate up to 24 12L OTE Niskin water sampling bottles.

Kongsberg Maritime Skipper DL850 Dual Axis Doppler Speed Log: Provides forward/aft (+/-) and port/starboard (+/-) ship speed measurements, both over ground and through water. The speed range is from 0-40 knots on both axis. The echo sounder has a max range of 100m.

Scientific Echo sounders

All of the following echo sounders are from Kongsberg Maritime. In normal mapping operations, the data from each of the sounders are recorded on the local acquisition machines in the Kongsberg file formats for more in-depth processing. They are recorded on SCS for use with displays, quality assurance and data transfers to the SOI website Falkor Status page. If you want to process any of these data for acoustic surveys, you will need the files in the native formats.

EM302 Deep water multibeam sonar: The EM302 is used for seafloor bathymetry, seafloor backscatter and water column backscatter. This sonar’s optimal depth is 1000-6000m, but it can log data from 10-8000m.

EM710 Shallow water multibeam sonar: The EM710 is used for seafloor bathymetry, seafloor backscatter and water column backscatter. This sonar has higher resolution in more shallow depths, and its operating range is up to 2000m, but it tends to stop collecting useful data by 1500m.

EK60 Split-beam fisheries sonar: The EK60 sonar is generally used for studying the plankton or fish in the water column. There are the following frequencies: 12kHz, 38kHz, 70kHz, 120kHz, 200kHz and 710kHz.

EA600 Single-beam hydrographic sonar: The EA600 is not frequently used for logging data. It’s primary function is to find the bottom quickly before an ROV dive or CTD cast or to compare to another sonar. There are the following frequencies: 12kHz, 38kHz, 120kHz and 200kHz. The 12kHz EA600 is one of two transducers that will collect data to the bottom of the Marianas Trench, roughly 11,000m in depth.