Impact of Combining Temperature Profiles from Different Instruments on an Analysis of Mixed Layer Properties

Abstract

For a joint analysis of temperature profiles from floats, expendable bathythermographs (XBTs), and other instruments (e.g., thermistor chains) the consistency of the profiles from the different sources needs to be ensured to avoid results with systematic errors. In this study profiles from the different instrument types are compared after they passed through a series of quality control tests. The different methods for quality control are presented. After ensuring that only high-quality profiles remain in the dataset, a statistical analysis of the temperature differences between adjacent profiles (in space and time) is performed. Potential regional differences as well as possible differences between the various float types are addressed. Finally, the impact of combining the profiles from floats with those from other instruments on gridded fields of the mixed layer temperature, thickness, and heat budget is discussed. It is found that the joint analysis yields more reliable results for the gridded fields and the heat storage rate. A large part of this improvement is a result of the reduced seasonal bias.