Integrated Ocean Skin and Bulk Temperature Measurements Using the Calibrated Infrared In Situ Measurement System (CIRIMS) and Through-Hull Ports

Abstract

The design and performance of a shipboard-integrated system for underway skin and bulk temperature is presented. The system consists of the Calibrated Infrared In situ Measurement System (CIRIMS) and through-hull temperature sensors. The CIRIMS is an autonomous shipboard radiometer system that measures the sea surface skin temperature Tskin for validation of satellite-derived sea surface temperature products. General design considerations for shipboard radiometer systems are discussed and the philosophy behind the CIRIMS design is presented. Unique features of the design include a constant temperature housing to stabilize instrument drift, a two-point dynamic calibration procedure, separate sky- and sea-viewing radiometers for simultaneous measurements, and the ability to use an infrared transparent window for environmental protection. Laboratory testing and field deployments are used to establish an estimated error budget, which includes instrumentation and environmental uncertainties. The combination of this testing and field comparison to the Marine-Atmosphere Emitted Radiance Interferometer (M-AERI) and Infrared SST Autonomous Radiometer (ISAR) instruments indicates that the CIRIMS meets the design goal of ±0.10°C accuracy. Temperature and pressure sensors were installed in custom-designed through-hull ports on the NOAA research vessel (R/V) Ronald H. Brown and the University of Washington R/V Thomas G. Thompson to complement the CIRIMS measurements. The ports allow sensors to be installed while the ship is in water and can accommodate a variety of sensors. The combined system provides the ability to measure near-surface temperature profiles from the skin to a depth of 5 m while underway.