An evaluation of adding a low-cost temperature string to NDBC Weather Buoys for monitoring heat content in the Caribbean Sea

In 2005, the National Data Buoy Center (NDBC) Weather Buoy network was expanded with 15 additional buoys in the Caribbean Sea in support of early detection and improved forecasts of Atlantic Hurricanes. These buoys have now become a standard and highly valuable asset to the Weather Buoy network, and as such, some will be upgraded with the modular Self Contained Ocean Observing Payload (SCOOP) to add new capabilities and value. One of these new capabilities includes real-time observations of subsurface temperature and salinity measurements. With this new ability, the enhanced Weather Buoys located in “hurricane alley” will be better positioned to support the real-time analyses of ocean heat content and high frequency weather phenomena linked to hurricanes. As part of this effort, NDBC assessed the utility of adding a low-cost thermistor string in lieu of traditional oceanographic sensors and deployed two SCOOP stations 13 km apart in the Caribbean Sea at Weather Buoy station 42058. One station was equipped with standard oceanographic sensors used as a reference, while the other station was equipped with a thermistor string. The purpose of the field test was verify the thermistor string observations meet NDBC accuracy requirements and to evaluate the ease of operation and durability within the field environment. The results indicate the thermistor string is acceptable within ±0.1°C greater than 80% of the time in the upper layer, yet when using the observations to calculate ocean heat content, there is an average error of 11%, Lastly, our results show the sensor response time, ease of deployment and durability of the thermistor string are not suitable for hurricane observations.