System design considerations for the retrieval of sea surface temperaturesin the NPOESS era

The National Polar-Orbiting Operational Environmental Satellite System (NPO ESS) requires improved accuracy in the retrieval of sea surface skin temper ature (SSTS) from its Visible Infrared Imager Radiometer Suite (VIIRS) sens or over the capability to retrieve bulk sea surface temperature (SSTB) that has been demonstrated with currently operational National Oceanic and Atmo spheric Administration (NOAA) satellites carrying the Advanced Very High Re solution Radiometer (AVHRR) sensor. Statistics show an existing capability to retrieve SSTB with a 1 sigma accuracy of about 0.8 K in the daytime and 0.6 K with nighttime data. During the NPOESS era, a minimum 1 sigma SSTS me asurement uncertainty of 0.5 K is required during daytime and nighttime con ditions, while 0.1 K is desired. Simulations have been performed, using PAC EOS(TM) scene generation software and the multichannel sea surface temperat ure (MCSST) algorithms developed by NOAA, to better understand the implicat ions of this more stringent requirement on algorithm retrieval methodologie s and system design concepts. The results suggest that minimum NPOESS SSTS accuracy requirements may be satisfied with sensor NE Delta T values of app roximately 0.12 K, which are similar to the AVHRR sensor design specificati ons. However, error analyses of retrieved SSTB from AVHRR imagery suggest t hat these more stringent NPOESS requirements map be difficult to meet with existing MCSST algorithms. Thus, a more robust algorithm, a new retrieval m ethodology, or more stringent system characteristics may be needed to satis fy SSTS measurement uncertainty requirements during the NPOESS era. It is c oncluded that system-level simulations must accurately model all relevant p henomenology and any new algorithm development should be referenced against in situ observations of ocean surface skin temperatures.