An evaluation of XBT depth equations for the Indian Ocean

For the purpose of finding XBT depth equations applicable to the entire Indian Ocean we carried out experiments through the collection of controlled XBT-CTD data on four cruises. These experiments were conducted in various locations of the Indian Ocean with highly variable physicochemical conditions. We estimated the mean depth error to vary from −2 to −27 m in a depth range of 0–750 m, which is comparable to that reported by Hanawa, Rual, Bailey, Sy and Szabados (1995, Deep-Sea Research I 43 (8), 1423–1451; hereafter referred to as HN-95), but is much higher than the manufacturer’s specified accuracy. The coefficients of the mean depth-time equation derived from the present data set do not differ significantly from HN-95. Depth error does not seem to be influenced by regional water characteristics. Our analysis confirms the applicability of the HN-95 equation for Indian Ocean as well.