Start-up transient of XBT measurement

The start-up transient of XBT measurements is statistically investigated for five types of recorder system: Z-60-16 11 and III by Murayama Electric Co., Ltd., and MV-130 by Tsurumi Seiki Co., Ltd., which are commonly used in Japan, and Sippican MK-9 and MK-12. which are popular in the United States and other countries. The UNESCO recommendation to exclude XBT-measured temperatures in the top 3.7 m layer from the bathythermograph report is justified within a nominal precision of 0.2degreesC For Tsurumi Seiki T-7 probes, However, it is shown that the depth where the transient ceases differs for different types of recorder. If we require a more strict accuracy constraint of 0.02degreesC, the estimated depth of the transient is 2 in for MK-130, MK-9 and MK-12,3 m for Z-60-161 III and 10 m for Z-60-16 II. (C) 2002 Elsevier Science Ltd. All rights reserved.