ACSPO Global SST from ABI

The ABI SST data are produced from GOES-16 (GOES-EAST)satellite using the NOAA Advanced Clear-Sky Processor for Ocean (ACSPO) v2.70 and from GOES-18 (GOES-WEST) satellite using the NOAA Advanced Clear-Sky Processor for Ocean (ACSPO) v2.90 enterprise system, GOES-17 (GOES-WEST) used ACSPO v2.71. Currently, for GOES-16 and GOES-18 near-real time (NRT) data are produced at STAR, with a latency of 2 to 6 hours (typically closer to 2 hours). For GOES-16 a reanalysis starting 2017-Dec-15 exists. The data are available in NetCDF4 format, compliant with the GHRSST Data Specifications v2 (GDS2). The data is archived with PODAAC with start date 2019-Feb-01 and end date 2023-Jan-10 (G17W) , 2022-Jun-7 (G18W) and 2017-Dec-15 (G16E) respectively. The NRT data is also available at this Coast Watch page as a 2week rotated buffer. There is a plan to reprocess the GOES-17 and -18 ABI data and to repeat the reprocessing of the GOES-16 data.

The data are reported hourly, in ABI Full Disk (FD), for view zenith angle not exceeding 68° in GHRSST Data Specifications v2 (GDS2) format, in swath projection (L2P) and 0.02° gridded L3C, 24 FDs per day, with a total data volume of 6.3GB/day for L2P and 0.5GB/day for L3C, respectively. For data assimilation applications (such as production of L4 analyses, especially those that blend satellite and in situ data), correction for the Sensor-Specific Error Statistics (SSES; reported in ACSPO files; Petrenko et al., 2016) biases is strongly recommended.

It should be noted that, due to an issue with its Loop Heat pipe, the L1b data for G17 was compromised for certain hours of the day and cannot be used to generate sensible SSTs. Therefore SSTs from G17 was not reported for the times between 09:00 UTC and 19:00 UTC. Since this is an hardware issue it is unlikely to be resolved in the near future.  (see Pennybacker et al., 2019). The new GOES-West (G18) is free from such problems.

In each valid water pixel (defined as ocean, sea, lake or river, up to 5km inland; note that in "invalid" pixels, defined as those with >5km inland, fill values are reported), the following layers are reported in both L2P and L3C: SSTs derived using multi-channel SST (MCSST; night) and Non-Linear SST (NLSST; day) algorithms (Petrenko et al., 2014); ACSPO clear-sky mask (ACSM; provided in each pixel as part of l2p_flags; Petrenko et al., 2010); SSES bias and standard deviation (Petrenko et al., 2016); NCEP wind speed; and ACSPO SST minus reference (Canadian Met Centre L4 SST). For L2P, brightness temperatures (BTs) in 3.9, 8.6, 10, 11, and 12 µm bands are also reported, for those users interested in direct "radiance assimilation" (e.g., NOAA NCEP, NASA GMAO).

Only ACSM "confidently clear" pixels (equivalent to GDS2 "quality level"=5; also reported for each pixel) should be used. The ACSM also provides day/night, land, ice, twilight, and glint flags. Note that users of ACSPO data have the flexibility to ignore the ACSM, derive their own clear-sky mask, and use BTs and SSTs in those pixels. They may also ignore ACSPO SST, and derive their own SSTs from the original BTs.

Both L2P and L3C SSTs are monitored and validated against in situ data (Xu and Ignatov, 2014) in SQUAM (Dash et al., 2010) and ARMS (Ding et al., 2017) systems, and BTs are monitored in MICROS (Liang and Ignatov, 2011).