Optimal Band

The importance of accurate measurements of ocean surface skin temperature is increasingly recognized. However, skin temperature measurements are made using complicated infrared radiometer systems that until now have been limited to ships. The main challenges that have limited accurate T skin measurements to ships are: the need for in situ two-point calibration using precision blackbodies the need for a separate sky measurement to correct for reflected downwelling radiance, uncertainty in emissivity, which depends on incidence angle and sea surface roughness I am currently developing a radiometer system called IRISS (InfraRed In situ Skin Sensing) for deployment on USVs and buoys with funding from the NSF Ocean Technology and Interdisciplinary Coordination Program. IRISS successfully addresses the first point by utilizing a simplified one-point calibration scheme. This project is to leverage this effort by developing an innovative and transformative technique to eliminate the need for a separate sky measurement and provide a significant reduction in the effect of emissivity. The technique uses an optimal spectral band in which the reflected sky radiance is from the atmosphere within a 1-2 km of the ship. The combination of the simplified calibration and optimal band technique will provide practical and accurate T skin measurements for USVs and buoys. Furthermore, the resulting simplicity and affordability could make it practical for widespread deployment as a standard measurement on the UNOLS fleet.