Geophysics

SISMER aims to ensure the consistency, continuity and accessibility of the geophysical data obtained by the French civil oceanographic research fleet (TGIR-FOF) so as to meet:

  • the requirements of international exchange agreements (Global and National Oceanographic Data Centres under IOC's IODE network, bilateral agreements, EU programmes...) 
  • the needs of the national community.
  • Ifremer's own needs.

The geophysical data archived at SISMER is:

  • conventionally exchanged under the IOC international agreements:
    • vertical bathymetry
    • gravimetry
    • magnetometry
  • obtained using sophisticated acquisition devices:
    • multibeam bathymetry (deep sea and shallow waters)
    • multibeam echosounder imagery
    • seismic reflection (launched in late 2002)
    • side-scan sonar (launched in 2007)
  • used to locate cruises and measurement positions.

Background

The oldest data archived at SISMER dates back to 1969.

Geographical coverage

SISMER stores surveys from all the oceans in databases. More than 10 million km² of seabed are covered by multibeam echosounders. The whole of the Economic Zone of mainland France beyond the continental shelf as well as a significant part of the Exclusive Economic Zone (New Caledonia...) has been covered. Furthermore, SISMER also stores a large number of commercial surveys conducted by Ifremer (cable route surveys, mineral resources, wreck searches, etc.)

Data types

The data stored includes:

  • bathymetric data from multibeam echosounders
  • bathymetric data from monobeam echosounders
  • gravimetric data
  • magnetometric data
  • imagery from multibeam echosounders or side-scan sonar
  • seismic reflection data
  • navigation data (vessel postions)

Data formats

The data are acquired during French oceanographic cruises in different standard formats:

  • NetCDF (self-describing format)
  • SEGD or SEGY for seismic reflection (binary format)

More information on file formats for geophysical data archived at SISMER.

Data processing and quality checks

For navigation data

Each cruise has a reference navigation file. This file is controlled, processed and validated by Genavir.

For scientific measurements

SISMER receives and stores "raw" data, i.e. as it is recorded at the end of the acquisition chain. It requires a certain number of quality control checks and processing operations in order to be usable. To do so, SISMER archives the calibration and instrumental bias correction parameters as well as, where relevant, the possible correction of anomalies in the recording submitted by GENAVIR under the responsibility of the chief scientists. These parameters are archived at the end of each cruise.

Upon reception of the data, SISMER applies a series of Quality Checks:

  • State of completeness of the documentation
  • State of completeness of the files
  • Format compliance
  • Control of time/space reference systems (dates, position)

SISMER also produces files in standard mgd format compiling data on vertical bathymetry, gravimetry and magnetism sampled every minute. For these files, the Quality Checks are completed with a control of the value of the measurements themselves:

  • Error and instrumental bias detection
  • Data consistency

The Quality Control tools for the Geophysical Databank are incorporated in the CARAIBES software developed by Ifremer.

More information on quality control of geophysical data archived at SISMER.

Data access

  • The oceanographic cruise database inventories all the deep-sea and coastal oceanographic cruises conducted by vessels of the French oceanographic fleet as well as the cruises conducted by French vessels which do not belong to the French oceanographic fleet or conducted in cooperation with foreign vessels.
  • Nautilus lists all the data acquired en route during offshore and coastal oceanographic cruises onboard vessels belonging to the French oceanographic fleet.
  • The French oceanographic fleet's publications database.
  • The annual reviews of the French oceanographic cruises also include the contact details of the chief scientists and the laboratories to be contacted to access data that is not archived at SISMER.
  • Scientific and/or technical review sheets of the cruises conducted.

Conditions of data use and access

  • Terms and conditions
    • General copyright rules apply to the distribution of the data.
    • The data user shall not use the data provided, either in whole or in part, for commercial purposes without prior written agreement from Ifremer and the data providers and shall ensure that the same applies to any employees or subcontractors. The data shall be used under the user's sole responsibility and at his/her own risk. Under no circumstances shall the user take legal action against Ifremer for damage of any nature which may results from the use of the data provided.
    • Scientific confidentiality
      • For the data obtained during research cruises, the confidentiality period is generally two years (for the two first years, permission must be obtained from the chief scientist).
      • In the case of data collected through an international or multi-organisation programme, this duration may vary.
      • Military confidentiality

The distribution of bathymetric data recorded in French territorial areas is subject to authorisation from the French Navy hydrographic and oceanographic service SHOM.

  • Other protection

Certain datasets can be protected at the request of the producer (for instance in the case of a private service contract). The permission of the producer must be obtained for all distribution.

  • Access conditions
    • If the data use is for scientific research purposes, Ifremer reserves the right to charge marginal access costs. The user is not entitled to disclose the data thereby obtained. A contract letter shall be drafted for each access request to precisely define the conditions of use. This letter is signed by both Ifremer and the institute requesting the data.
    • If the data use is for commercial purposes, a quote will be provided before disclosing any data (sismer@ifremer.fr).

Contact

For all further enquiries, please contact the SISMER service (sismer@ifremer.fr).