|Last edited: Oct-19-2010|
NESDIS heritage SST products have been generated using the Main Unit Task (MUT) system since the late 1970s from AVHRR data onboard NOAA and MetOp-A satellites (McClain, 1989; McClain et al., 1985; Walton, 1988; Ignatov et al., 2004).
SST and auxiliary Data in MUTAVHRR 4 km global area coverage (GAC) L1b data are processed by 2×2 GAC arrays, resulting in an effective spatial resolution of MUT SST of ~8km. Not all clear-sky pixels are retained, due to a complex sub-sampling based on the merging of AVHRR and HIRS footprints. MUT SST retrievals are limited to within VZA<~±54° defined by HIRS swath.
SST products are generated and saved in platform-specific SSTOBS rotated files, each file retaining ~8 days of data. SST retrievals are reported along with the algorithm flag (Night 152: MCSST; Day 151: NLSST), UTC, latitude (Lat), longitude (Lon), view zenith angle (VZA), solar zenith angle (SZA), relative azimuth angle (RZA), AVHRR reflectances and brightness temperatures, and climatological SST (Bauer and Robinson, 1985).
Analyzed on these page are weekly archived SSTOBS files from NOAA-16, -17, -18, MetOp-A, and NOAA-19 satellites from June 2004-present.
Three modifications to the original MUT SSTOBS files for SQUAM analyses:1. SST on SSTOBS is provided with only one digit after the decimal point. Operational regression coefficients were applied to the brightness temperatures and VZA (which are reported to 2 decimals) and SSTs were regenerated with a better digitization.
2. Several reference SSTs were appended to SSTOBS, in addition to already available Bauer-Robinson (1985) climatology: weekly and two daily Reynolds, low and high resolution RTG, OSTIA, and ODYSSEA.
3. Some additional parameters were calculated such as local time, glint and scattering angles and used as diagnostic parameters.