MBTs measure temperature down to the depth of 250m from the decks of slowly moving ships. The following studies attempt to correct a bias in MBT measurements created by systematic errors in depth (pressure) and temperature sensors.
Ishii, M. and M. Kimoto, 2009: Reevaluation of historical ocean heat content variations with an XBT depth bias correction. J. Oceanogr. 65, 287299, doi:10.1007/s10872-009-0027-7. Ishii and Kimoto corrections.
Levitus, S, J. Antonov, T. Boyer, 2009: Global ocean heat content 1955-2007 in light of recently revealed instrumentation problems. Geophys. Res. Lett. , 36, L07608, doi:10.1029/2008GL037155. Levitus et al. corrections; July, 2019 corrections.
Gouretski, V. and F. Reseghetti, 2010: On depth and temperature biases in bathythermograph data: Development of a new correction scheme based on analysis of a global ocean database. Deep-Sea Research I, Vol. 57(6), pp. 812-834, doi:10.1016/j.dsr.2010.03.011. Gouretski and Reseghetti corrections
Gouretski and Reseghetti Updated Corrections
Zcorrected = Zoriginal * Strech
Where sStretch is provided in table 1 at 1m depth interval.
Tcorrected = Toriginal - thermal_bias
Where the tThermal_bias is provided in table 2.
Gouretski and Reseghetti Original Corrections
Below 40 meters: S = 1 + b + a/Zoriginal, where S is the stretching , Zoriginal is the observed depth.
Above 40 meters: S = c + (Zoriginal - 5) * (d - c)/35, where d = 1 + b + a/40
The values of a, b and c for the years 1941 to 2003 are provided in table 1.
The corrected depth, Zcorrected = Zoriginal * S
Tcorrected = Toriginal - Thermal bias
Thermal bias for MBT for the years 1941 to 2003 are presented in table 2.