AVHRR GAC Reanalysis v2 (RAN2) Global SST data are produced at NOAA STAR 
using the Advanced Clear-Sky Processor for Ocean (ACSPO) SST system, from
3 afternoon (NOAA-07,09, 11, 14, 16, 18, 19),  2 early-morning satellites (NOAA-12 and 15) and 1 mid-morning satellites (NOAA-17). 

Data are provided in GHRSST Data Specification v2 (GDS2) NetCDF format, 
as L2P (swath) and L3U (gridded, 0.02deg).

L2P data  and L3U data  cover from 1 Sep 1981 to 18 Oct 2021. 
Data are organized by Platform/Level/YYYY/DDD. 

Further information on the data can be found at 
https://coastwatch.noaa.gov/cw/satellite-data-products/sea-surface-temperature/acspo-avhrr-gac.html
and
https://www.mdpi.com/2072-4292/8/4/315