SENSITIVITY OF SEA SURFACE TEMPERATURE RETRIEVAL TO SEA SURFACE EMISSIVITY

To estimate sea surface temperature(SST) with high accuracy from radiometrie measurements,it is no longer acceptable to assume that sea surface emissivity is unity or any other constant.This note presents an investigation of the desirable emissivity accuracy in relation to retrieval.It was found that 1% error in surface emissivity can cause up to 0.7 K error in the retrieved SST,although this sensitivity is often reduced to about 0.5 K on average because of the downward atmospheric radiation at surface partially compensates for the emissivity error.Since the downward atmospheric radiation ratio is controlled to a large extent by the integrated water vapor in the atmosphere and,secondarily,by view angle,the sensitivity of SST retrieval to surface emissivity has been computed as a function of these two parameters.