A New Method of Calculating Ocean Temperatures Using Expendable Bathythermographs

A newly developed method is proposed to simplify the measurement of ocean temperatures and heat content. That method, which makes use of expendable bathythermograph probes (XBTs), is able to account for variations in the probes such as weight, size, drop height, and wire length. Additionally, this new method accounts for variations in the conditions of the drop region, such as ocean temperature and salinity. The method requires the determination of the drag coefficient which corresponds to the probe’s travel through water. This coefficient is introduced into a dynamic equation in which the position of the probe is calculated at a sequence of time steps. The calculated depths are matched with corresponding local temperatures to enable a determination of ocean heat content. The method outlined here avoids the reliance upon experimental correlations which are traditionally used for ocean-temperature measurements. To validate the method, it was applied to two calibrated XBT experiments. It is shown that the new method provides results that are virtually identical with results obtained from industry-standard techniques, and it is possible that the method can be applied to historical archives.