The Submesoscale from VIIRS Imagery-Band (375 m) Sea Surface Temperature Fields

Abstract:

The Visible-Infrared Imager-Radiometer Suite (VIIRS) carried on the Suomi National Polar-orbiting Partnership (Suomi NPP) spacecraft makes measurements in spectral bands in the infrared at a nadir spatial resolution of 750 m, in what are referred to as the Moderate Resolution Bands (M-Bands), and at a nadir spatial resolution of 375 m in “Imagery Bands” (I-Bands). The spectral coverage of M-Bands allows for the high quality retrieval of sea surface temperature (SST) under cloud-free conditions. In particular, the M-Band suite includes a “split window” in the 10 to 12 micrometer range with which correction for atmospheric water vapor can be made while avoiding issues associated with solar reflection, which afflicts observations in some of the shorter wave-length spectral windows during daylight hours. Unfortunately, there is only one I-Band channel in the 10 to 12 micrometer range precluding the same approach used for M-Band retrievals. In this presentation, we discuss an algorithm developed at the University of Rhode Island that makes use of the atmospheric correction available from M-Band retrieval algorithms together with I-Band radiances to produce a high quality 375 m SST product. The M-Band retrievals used are those from NOAA’s Advanced Clear Sky Processor for Oceans (ACSPO) program. In comparisons with ship-borne radiometer SST retrievals, we show that the I-Band retrievals are of similar quality to the underlying M-Band retrievals. We then go on to demonstrate the sub-kilometer scale of the features resolved in the I-Band retrievals as well as how these data may be used to infer near-surface currents on a spatial grid of order 10 kilometers.