Evaluation of a Low-Cost and Accurate Ocean Temperature Logger on Subsurface Mooring Systems

Abstract

AbstractMonitoring seawater temperature is important to understanding evolving ocean processes. To monitor internal waves or ocean mixing, a large number of temperature loggers are typically mounted on subsurface mooring systems to obtain high-resolution temperature data at different water depths. In this study, we redesigned and evaluated a compact, low-cost, self-contained, high-resolution and high-accuracy ocean temperature logger, the TC-1121. The newly designed TC-1121 logger is smaller and more robust, and its sampling interval can be automatically changed by indicated events. The logger’s initial accuracy is ±0.002°C, and its effective resolution is about 0.0001°C. The drift error of all six TC-1121 temperature loggers during a 450-day experiment was less than ±0.002°C. They are being widely used in many mooring systems to study internal wave and ocean mixing. The logger’s fundamental design, noise analysis, calibration, and drift test are discussed. A long-term sea trial in the South China Sea was completed successfully and demonstrated the effectiveness of the logger.