Metadata Report for BODC Series Reference Number 1755590
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
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Problem Reports
No Problem Report Found in the Database
Data Access Policy
Open Data supplied by Natural Environment Research Council (NERC)
You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."
Narrative Documents
D381B Microstructure Profiler Instrumentation
The following contains information taken from the D381 cruise report.
The microstructure profiler deployed during the cruise was a loosely tethered MSS90 profiler (s/n 034) produced by Sea and Sun Technology GmbH and ISW Wassermesstechnik. The profiler has a drop speed of 0.85 ms-1and typically fell to approximately 200 metres producing up to seven profiles per hour. The instrument includes two PNS shear probes as well as conductivity, temperature and pressure sensors.
The following table details the sensor configuration of the profiler:
| Sensor | Model | Serial number | Comments |
|---|---|---|---|
| Sea and Sun Technology (SST) microstructure profiler unit | MSS 90 | 034 | - |
References
Naveira-Garabato, A. C. and Allen J.T. et al. (2012). 'Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)'. Cruise Report No. 18 National Oceanography Centre, Southampton.
D381B MSS Microstructure Profiler: Processing undertaken by BODC
A total of 598 individual ASCII .TOB files were supplied to BODC by the data originator. These were accompanied by 629 associated raw (.MRD) data files, as output directly from the profiler.
The .TOB files were reformatted to BODC internal QXF format and the originator's variables were mapped to BODC parameter codes as follows:
| Originator's variable | Units | Description | BODC parameter code | Units | Comments |
|---|---|---|---|---|---|
| press | dbar | Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level | PRESPR01 | dbar | No unit conversion required |
| vel | dbar/s | Downward velocity of sensor package in the water body | CTDLOWRT | m/s | Assumption that 1 dbar ~ 1 metre |
| tiltx | deg | Orientation (pitch) of measurement platform by inclinometer | PTCHEI01 | deg | No unit conversion required |
| tilty | deg | Orientation (pitch) of measurement platform by inclinometer (second sensor) | PTCHEI02 | deg | No unit conversion required |
| peps | W/kg | Not reformatted by BODC | |||
| epsilon1 | W/kg | Not reformatted by BODC | |||
| epsilon2 | W/kg | Not reformatted by BODC | |||
| epsilon | W/kg | Log10 turbulent kinetic energy dissipation {epsilon} per unit mass of the water body by turbulence profiler shear sensor | EPSIPM01 | W/kg | No unit conversion required |
| TEMPcor | °C | Temperature of the water body | TEMPPR01 | °C | No unit conversion required. |
| COND | mS/cm | Electrical conductivity of the water body | CNDCZZ01 | S/m | unit conversion =/10 |
| sal | PSU | Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm | PSALPR01 | Dimensionless | No unit conversion required. |
| sig-t | kg/m3 | Sigma-theta of the water body by computation from salinity and potential temperature using UNESCO algorithm | SIGTEQ01 | kg/m3 | No unit conversion required. |
| th-sigma | Dimensionless | Not reformatted by BODC | |||
| N2 | (1/s)2 | Brunt-Vaisala frequency squared of the water body by turbulence profiler precision CTD | BVFSTP01 | (1/s)2 | No unit conversion required |
| N | 1/s | Not reformatted by BODC | |||
| Thermdiss | K2/s | Not reformatted by BODC | |||
| th-ntc | Dimensionless | Not reformatted by BODC |
Screening
The data were screened using BODC in-house software Edserplo. Any data that were outside of the expected range or improbable were flagged accordingly.
RRS Discovery Cruise D381B Microstructure Profiler MSS90 Originator Processing
Sampling strategy
A total of three time series of microstructure profiler measurements were made during leg B of OSMOSIS cruise D381. The following table summarises the profiles made:
| Survey station | MSS profiles | Deployment dates | Comments |
|---|---|---|---|
| A | D3810012 - D3810250 (238 profiles) | 22:35 2012-09-17 - 11:54 2012-09-19 | 5.5 hour gap in recording due to cable failure. |
| B | D3810251 - D3810453 (202 profiles) | 07:05 2012-09-22 - 12.47 2012-09-23 | 3.5 hours gap in recording due to cable split and re-deployment. |
| C | D3810454 - D3810629 (175 profiles) | 20:30 2012-09-27 to 00:05 2012-09-29 |
Gaps of approximately one hour also occurred during stations A and C in order for CTD profiles to take place.
The MSS001 profiler provided by SAMS was equipped with two velocity shear sensors, a temperature sensor, standard CTD sensor for precision measurements, a two component tilt sensor and surface detection sensor.
Data processing
Each profile generated a single raw .MRD file. These were post-processed after the cruise following SAMS standard procedures for MSS data, which utilise the ISW processing software (MSSpro). A summary of the main SAMS processing steps is presented below. More comprehensive details are available in the MSSpro software manual.
SAMS processing steps:
- Conversion of sensor output voltages to shear measurements using the gradient of velocity as a function of pressure through the water column
- Application of calibration coefficients specific to the shear probes
- Checking of shear spectra with Nasmyth's universal spectrum of turbulence in the ocean and subsequent application of a low pass filter to remove high frequency noise from the profiles
- Calculation of the dissipation rate of turbulent kinteic energy (epsilon) over the measurable range from the profiler. Spectral fitting using the Nasmyth spectrum to address those frequencies outside of the range
- Generation of 1 metre-binned ASCII (.tob) files containing the key variables identified by the originator.
The raw .MRD files are available on request. A calibrated version of this data is also available in originator format.
References
Naveira-Garabato, A. C. and Allen J.T. et al. (2012). 'Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)'. Cruise Report No. 18 National Oceanography Centre, Southampton.
Sea and Sun Technology MSS 90 Microstructure Profiler
A multiparameter probe used to measure micro-scale water stratification as well as the intensity of small scale turbulence in the water column in marine and limnic environments. The instrument can be used for free sinking or rising measurements. The instruments sinking or rising velocity can be adjusted by a combination of weights and buoyancy elements. It has a depth rating of approximately 500 m, samples at 1024 Hz and is equipped with high resolution micro-structure and turbulence sensors (temperature, current shear) and standard CTD sensors (temperature, conductivity, pressure). All microstructure channels have a response time of less than 12 ms. The unit includes internal sensors to control for vibrations and tilt internally.
The system comprises the profiler, a winch, a probe interface and data acquisition computer. Additional sensors, such as oxygen and optical scattering, can be attached to the profiler. The instrument can support up to a maximum of nine sensors.
There are two different models available which have the same electronic and sensor equipment, with the difference relating to the size and weight of the instruments, see the table below for further details. The shear sensor data quality of the MSS90L is however superior due to the higher mass and stability.
| Technical Data/Dimensions | MSS 90 | MSS 90L |
|---|---|---|
| Depth range | 500 m | 500 m |
| Weight in water | 10 kg | 12.5 kg |
| Depth range | 500 m | 500 m |
| Length of housing | 1 m | 1.25 m |
| Standard sensor equipment | Pressure, temperature and conductivity 2 x Shear Temperature microstructure sensor FP07 Acceleration sensor for measuring the profiler vibration | Pressure, temperature and conductivity 2 x Shear Temperature microstructure sensor FP07 Acceleration sensor for measuring the profiler vibration |
| Sensor plugs | 9 | 9 |
| Optional sensors | Turbidity Fluorescence Tilt (2axis) Oxygen pH | Turbidity Fluorescence Tilt (2axis) Oxygen pH |
| Data channels | 16 | 16 |
| Sampling rate | 1024 s-1 | 1024 s-1 |
| Resolution | 16 Bit | 16 Bit |
| Housing | Seamless drawn titanium tube | Seamless drawn titanium tube |
| Channels response time | <12 ms | <12 ms |
Further details can be found in the manufacturer's manual.
Project Information
Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)
Background
The Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS) consortium was funded to deliver NERC's Ocean Surface Boundary Layer (OSBL) programme. Commencing in 2011, this multiple year study will combine traditional observational techniques, such as moorings and CTDs, with the latest autonomous sampling technologies (including ocean gliders), capable of delivering near real-time scientific measurements through the water column.
The OSMOSIS consortium aims to improve understanding of the OSBL, the interface between the atmosphere and the deeper ocean. This layer of the water column is thought to play a pivotal role in global climate and the productivity of our oceans.
OSMOSIS involves collaborations between scientists at various universities (Reading, Oxford, Bangor, Southampton and East Anglia) together with researchers at the National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS) and Plymouth Marine Laboratory (PML). In addition, there are a number of project partners linked to the consortium.
Scientific Objectives
- The primary goal of the fieldwork component of OSMOSIS is to obtain a year-long time series of the properties of the OSBL and its controlling 3D physical processes. This is achieved with an array of moorings (two nested clusters of 4 moorings, each centred around a central mooring) and gliders deployed near the Porcupine Abyssal Plain (PAP) observatory. Data obtained from this campaign will help with the understanding of these processes and subsequent development of associated parameterisations.
- OSMOSIS will attempt to create parameterisations for the processes which determine the evolving stratification and potential vorticity budgets of the OSBL.
- The overall legacy of OSMOSIS will be to develop new (physically based and observationally supported) parameterisations of processes that deepen and shoal the OSBL, and to implement and evaluate these parameterisations in a state-of-the-art global coupled climate model, facilitating improved weather and climate predictions.
Fieldwork
Three cruises are directly associated with the OSMOSIS consortium. Preliminary exploratory work in the Clyde Sea (September 2011) to hone techniques and strategies, followed by a mooring deployment and recovery cruise in the vicinity of the Porcupine Abyssal Plain (PAP) observatory (in late Summer 2012 and 2013 respectively). Additional opportunist ship time being factored in to support the ambitious glider operations associated with OSMOSIS.
Instrumentation
Types of instrumentation and measurements associated with the OSMOSIS observational campaign:
- Ocean gliders
- Wave rider buoys
- Towed SeaSoar surveys
- Microshear measurements
- Moored current meters, conductivity-temperature sensors and ADCPs
- Traditional shipboard measurements (including CTD, underway, discrete nutrients, LADCP, ADCP).
Contacts
| Collaborator | Organisation |
|---|---|
| Prof. Stephen Belcher | University of Reading, U.K |
| Dr. Alberto C Naveira Garabato | University of Southampton, U.K |
Data Activity or Cruise Information
Cruise
| Cruise Name | D381B |
| Departure Date | 2012-09-14 |
| Arrival Date | 2012-10-03 |
| Principal Scientist(s) | John T Allen (National Oceanography Centre, Southampton) |
| Ship | RRS Discovery |
Complete Cruise Metadata Report is available here
Fixed Station Information
No Fixed Station Information held for the Series
BODC Quality Control Flags
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
| Flag | Description |
|---|---|
| Blank | Unqualified |
| < | Below detection limit |
| > | In excess of quoted value |
| A | Taxonomic flag for affinis (aff.) |
| B | Beginning of CTD Down/Up Cast |
| C | Taxonomic flag for confer (cf.) |
| D | Thermometric depth |
| E | End of CTD Down/Up Cast |
| G | Non-taxonomic biological characteristic uncertainty |
| H | Extrapolated value |
| I | Taxonomic flag for single species (sp.) |
| K | Improbable value - unknown quality control source |
| L | Improbable value - originator's quality control |
| M | Improbable value - BODC quality control |
| N | Null value |
| O | Improbable value - user quality control |
| P | Trace/calm |
| Q | Indeterminate |
| R | Replacement value |
| S | Estimated value |
| T | Interpolated value |
| U | Uncalibrated |
| W | Control value |
| X | Excessive difference |
SeaDataNet Quality Control Flags
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
| Flag | Description |
|---|---|
| 0 | no quality control |
| 1 | good value |
| 2 | probably good value |
| 3 | probably bad value |
| 4 | bad value |
| 5 | changed value |
| 6 | value below detection |
| 7 | value in excess |
| 8 | interpolated value |
| 9 | missing value |
| A | value phenomenon uncertain |
| B | nominal value |
| Q | value below limit of quantification |
