Four-hour SST is a 4-hour composite SST produced every 4 hours at 2km resolution, using all available satellite SST:

10min Himawari-8 and Himawari-9 from the Bureau of Meteorology
N15, N18, N19 from BoM
MetopA & MetopB from NOAA
VIIRS Suomi-NPP from NOAA

Method: Step 1: 4-hour composites of Him8 SST (with 2-4km resolution) are made, taking the median SST at every pixel. Step 2: the final composite is made using the Him8 composite and all other available AVHRR and VIIRS SST. The composite is made in two steps so that if the BoM Him8 SST is unavailable we can replace it with NOAA hourly Him8 composites. All SST is adjusted by the SSES bias before compositing and an offset of 0.17C is added to obtain the bulk SST.

Available: 11 Aug 2017 to present

SST: All SST of QL>=4 (QL=4 or 5 are the BoM's highest Quality Levels)

Filled SST: the gaps in the SST are filled with the most recent previous composites

SST Age: the age of the Filled SST

Wind Speed: BoM ACCESS-R 3hr average wind speed and direction for the analysis time