Hull Contact Sensor
The Sea-Bird Electronics SBE 48 sensor is a high-accuracy temperature recorder with non-volatile memory, designed for shipboard determination of sea surface temperature. Mounted with magnets just below the water line, the SBE 48's temperature sensor is in contact with the inside of the ship's hull. For more information see here.
Hull Contact Sensor Tests
Two SBE 48 hull-contact temperature sensors were tested in the Bureau of Meteorology sensor calibration lab during 2008 and two installed on the RV Southern Surveyor and RV Cape Ferguson for comparison tests with the SBE 3 and SBE 38 calibrated thermistors installed in the thermosalinograph water intakes on both vessels. Refer to Beggs et al. (2012) for further details.
Both studies indicate that the SBE 48 is capable of providing ship SST observations of sufficient accuracy for satellite SST validation. If the SBE 48 has good thermal contact with the hull, is positioned well below the water line away from on-ship heat sources, and the sensor and surrounding hull is sufficiently insulated from the interior ship’s atmosphere, the hull-contact sensor should provide a bulk sea surface temperature measurement approaching the accuracy of Sea-Bird Electronics SBE 3 and SBE 38 water intake temperatures. Sea-Bird Electronics quotes the initial accuracy of the SBE 48 as ±0.002°C and the SBE 3 and SBE 38 as ±0.001°C.
Infrared Autonomous SST Radiometer (ISAR)
The infrared SST autonomous radiometer (ISAR) is a self-calibrating instrument measuring in situ SST skin accurate to 0.1°C rmse. The ISAR is capable of continuous deployment for up to 3 months aboard volunteer observing ships in all weather conditions while maintaining accurate calibration.
For more information see the ISAR website and this report on the ISAR installation and quality control.