Checking and validation of BATOS data on board FASTEX ships


general information
VICTOR BUGAEV section
R/V Le SUROIT section
The Ægir section
 VICTOR BUGAEV page
R/V Le SUROIT page
The Ægir page

General information

checking and validation provided by METEO FRANCE / CNRM / GMEI /4M
experiment: FASTEX

ship nameship call sign BATOS dataon board staff observations
fromtofromto
VICTOR BUGAEV (Ukraine)EOGW01 January 1997, 00UTC01 March 1997, 00UTC05 January 1997, 00UTC01 March 1997, 00UTC
R/V Le SUROIT (France)FZVNfrom 07 January 1997, 17UTC28 February 1997, 23UTC01 January 1997, 09UTC28 February 1997, 21UTC
Ægir (Iceland)TFTA05 January 1997, 21UTC22 February 1997, 11UTC05 January 1997,21UTC22 February 1997, 09UTC

Quality control processing:
BATOS data were compared with the on board instrumentation data (named 'operator' data afterwards).
For each available parameter, automatic BATOS data and operator measurements were plotted and compared together.
In particular, each time the difference BATOS and 'operator' values was greater than a given value, data were visually examinated.
It led to point out suspect data which were manually checked and flagged if necessary.

In conclusion, when available and of good quality (flag set to 'good'), BATOS data will be considered as reference data and have to be used rather than 'operator' data. In the other cases, free hand is given to the data user.

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Remarks on VICTOR BUGAEV data

  • pressure measurements
    The temporal evolution of each pressure measurement seems to be correct, and differences between are related to the response time (aneroid barometer and PTB220 barometer respectively). No data removed or flagged as suspect or bad.

  • temperature measurements
    differences between BATOS temperature and 'operator' temperature measurements are most of all related to the response time of each measurement sensor (PT100 for BATOS, mercury thermometer for the 'operator').
    2 BATOS values flagged as suspect, 1 removed

  • humidity measurements
    Ukrainian on board meteorologists used a psychrometer to measure the relative humidity. In comparison, the BATOS humidity sensor was more sensitive and responded more quickly.
    6 BATOS values removed.

  • wind direction and speed measurements
    note: the BATOS YOUNG anemometer was destroyed by a storm on the January, 25th; a new sensor was installed on the January, 31st, during the Halifax call.
    Sensors were installed at the same level on the mast. BATOS and 'operator' data are of good quality, well correlated. Only some BATOS wind data removed when the anemometer was destroyed.
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    Remarks on the R/V Le SUROIT data

  • pressure measurements
    On the ship were also available pressure measurements from the meteorological mast sensor (named 'mast data' after), every minute (averaged value from a 10-second recording). So, three different data sets were used for the inter-comparison: 1-hour BATOS data, operator data and mast data.
    Known BATOS problems:
  • 16,17 February: interventions on the BATOS software because of problems with the measurement of the "log" speed
  • 18 February: no data; as reported on the log, lots of interventions on the BATOS software which couldn't stock values needed to compu te averaged data
  • 19 February: METEO-FRANCE/CNRM/GMEI/4M sent instructions to the staff on board
  • no data for the following dates: 22, 23 and 28 February
    •  Samplings of the new sensors used during FASTEX show a maximum correction of +0.7 hPa, in the conditions of pressure and temperature encountered during the field phase.
    An averaged 2hPa off-set can be noticed between BATOS and 'operator' data, certainly due to the holosteric barometer used for on board observations.

  • temperature measurements
    BATOS temperature is less perturbed and quite always available because:
  • independence from the ship navigation parameters
  • data don't need any computation

  • humidity measurements
    The general appearance of BATOS humidity curve looks very good, compared to the 'operator' humidity measurements (use of a psychrometer, generally of poorer quality).
    Saturation (100% humidity) is rare at sea surface. No saturing fog period observed during the experiment.
    note: BATOS sensor destroyed on the February, 13th at 15UTC.

  • wind direction and speed measurements
    Operator data are higher than BATOS ones, although both sensors were installed at the same place on the ship. Differences have to be related to the difference of sampling between sensors.
    One-minute averaged data were also available on the meteorological mast. These data confirm BATOS measurements.
    note: no BATOS data for the following dates: February, 16, 17, 18, 19, 22, and 23.
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    Remarks on the Ægir data

    General comments on BATOS missing data:
    As reported on the Ægir log, a lot of interventions were made on the BATOS software. This was a great problem for BATOS, which couldn't stock values needed to compute averaged data, nether send messages on the GTS.
    After the 11 February, 9UTC, 'operator' observations are still every 3 hours, but BATOS data are available every hour (after a change in the BATOS software, asked by METEO-FRANCE/CNRM/GMEI/4M to the staff). No more intervention appeared on the log, recorded data are correct.
  • pressure measurements
    Between the 13 January and the 18 January, a problem occured on the BATOS pressure instrumentation. Data concerned by this problem were removed.
  • temperature measurements
    Differences are sometimes large between the two data sets (BATOS and 'operator'), but data seem to be consistent, refering to the temporal evolution of each parameter.
    During the period 7 Jan, 12UTC to 13 January, 12UTC, differences can be explained by very calm winds.
  • humidity measurements
    No 'operator' data for this parameter.
  • wind direction and speed measurements
    Nothing in particular to report.
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    Miscellaneous information:

  • Victor BUGAEV:
  • Significant differences between BATOS and 'operator' pressures , temperatures , humidities .
  • R/V Le SUROIT:
  • Significant differences between BATOS and 'operator' pressures , temperatures , humidities , wind directions and wind speeds .
  • Missing data summary statement .
    •
  • The AEGIR:
  • Significant differences between BATOS and 'operator' pressures , temperatures , wind directions and wind speeds .
  • Missing data summary statement .
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    Updated: 22 April 1999