Effect of emissivity on shipboard sea surface skin temperature measurements

Sea surface temperature (SST) is an essential variable for numerical weather prediction and global climate modeling. Sea surface skin temperature (SST
_skin
) measurements are required for the validation of satellite SST products. Several radiometers for in situ SST
_skin
measurements have been developed. The infrared SST autonomous radiometer (ISAR) is a self-calibrating instrument with an accuracy of 0.1 K. An ISAR developed by the University of Southampton has been deployed on the research vessel Dong Fang Hong II of Ocean University of China since 2009. A model is applied to calculate wind-roughened sea surface emissivity using the in situ wind data collected during the cruises in 2013 and 2014. The effect of emissivity on the retrieved SST
_skin
by ISAR is analyzed. The results show a magnitude of 0.1 K to 0.2 K under high wind speed. Considering the requirement of 0.1 K accuracy of ISAR, it is important to estimate appropriate wind-roughened sea surface emissivity for SST
_skin
measurements.