Ocean Surface Skin Temperature Measurements using an Optimal Spectral Band

This project is to develop a novel technique for measuring the ocean skin temperature from a radiometer. Normally skin temperature measurements from radiometers have been made from ships and have required in situ two-point calibration, a separate sky measurement to account for downwelling radiance, and entail uncertainty in the emissivity. The PI is already developing a radiometer that utilizes a single point calibration scheme. This project will leverage the ongoing radiometer development to eliminate the need for a sky measurement and reduce the effect of emissivity uncertainty. The result will be that practical and accurate skin temperature measurements can be made from unmanned surface vehicles and buoys as well as oceanographic research vessels. The availability of accurate skin temperature observations could lead to improved models for near-surface stratification and validation of satellite measurements. This project leverages an ongoing NSF project by the PI to develop the InfraRed In situ Skin Sensing (IRISS) radiometer for the further development of a technique that eliminates the need for separate sky measurements in measuring ocean skin temperature and provides 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 combined simplification of a single ambient temperature calibration and no sky measurement will significantly increase the practicality and accessibility of ocean surface skin temperature measurements. As a result it will be possible to make practical and accurate skin temperature measurements from a variety of observation platforms, including USVs, buoys, and ships. The goal is to facilitate skin temperature measurements with accuracies comparable to those currently made from oceanographic research vessels. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.