Detection of systematic errors in XBT data and their correction

Kimio Hanawa, Hiroyuki Yoritaka

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Comparison experiment between XBT of T-7 probe and CTD was conducted at 15 stations in the sea area centered on 29°N, 135°E in December 1985. There were systematic errors in XBT temperature profiles in comparison with CTD temperature profiles. The main cause of errors was attributed to an error in the free-fall speed of the XBT probes which was provided by the XBT maker. A previous equation for depth correction proposed by Heinmiller et al. (1983) could not give effective correction for our data. A new equation between the probe depth and the elapsed time from landing of the probe on the water was obtained by the method of adjusting temperature gradients of XBT profiles to those of CTD profiles. This equation agreed with the theoretical result given by Seaver and Kuleshov (1982) much better than that of Heinmiller et al. (1983). Systematic errors due to a scatter of values of the reference resistance and variation of B-constant of thermistors used in XBT also seemed to exist. After an adjustment using the temperature difference between XBT and CTD in the mixed layer with depths of about 100 m, the standard deviation of temperature difference between XBT and CTD from the surface to the depth of 750 m was 0.14°C.

Original languageEnglish
Pages (from-to)68-76
Number of pages9
JournalJournal of the Oceanographical Society of Japan
Issue number1
Publication statusPublished - 1987 Feb

ASJC Scopus subject areas

  • Environmental Science(all)
  • Soil Science
  • Engineering(all)
  • Earth-Surface Processes
  • Earth and Planetary Sciences(all)


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