NESDIS has established a near real-time (NRT) web-based Sea Surface Temperature (SST) Quality Monitor (SQUAM) for monitoring SST products. The initial objective was to monitor NESDIS AVHRR Level 2 (L2; data at the observed pixels) SST products, which was further extended to Level 3 (L3; gridded L2 data with gaps) Pathfinder SSTs. Subsequently, following the interest from the Level 4 (L4; gap-free gridded analysis data) community, and in the spirit of the Group for High Resolution SST (GHRSST) collaborative efforts, SQUAM functionality has been extended to include cross-comparisons of various L4 analysis SST fields. The L4-SQUAM also provides NESDIS contribution to the GHRSST Inter-Comparison Technical Advisory Group (IC-TAG).
The SQUAM is aimed at serving the needs of both SST users and producers. The three main modules of SQUAM — L2, L3 and L4 — currently monitor in NRT: [a] all global L2 AVHRR SSTs (generated at NESDIS, NAVOCEANO, and O&SI SAF, respectively), [b] Pathfinder v5.0 (1985-2009) L3, and [c] thirteen L4 products (with 1-day latency; full history retained), including two Reynolds OISST (AVHRR, AVHRR+AMSR-E), two OSTIA (operational and reanalyzed), two RTG (high and low resolution), NAVO K10, NESDIS Multi-SST, JPL G1SST, CMC 0.2°, ODYSSEA, BoM GAMSSA, and GMPE product. Work is underway to add JPL MUR, RSS -MW and -IR+MW, NRL NCODA, JMA MGDSST, and DMI analysis.
Analyses are performed using differences "SST1 – SST2", whose distributions are evaluated for proximity to Gaussian shape. The emphasis is on visual yet quantitative analyses in a global domain, via plotting maps, histograms, time series and various dependencies and Hovmöller diagrams. Also, cross-platform consistencies for L2 SSTs are checked using a double differencing (DD) technique.
"L2/3 – L4" and "L4 – L4" are analyzed and all SST products are consistently validated against uniformly quality controlled in situ data, available from the NESDIS in situ SST Quality Monitor (iQuam). In situ data are sparse and not available in NRT, in sufficient numbers and quality controlled, whereas "L2/3/4 – L4" analyses are available in NRT and in a global domain, with much larger match-up datasets resulting in robust statistical analyses.
In polar-SQUAM, adding MODIS and NPOESS VIIRS is our next priority. Prototype geo-SQUAM has been set-up which currently reports about 3 years worth of NESDIS processed SEVIRI data, as a part of preparedness towards the GOES-R ABI era. Efforts are also underway to include SEVIRI SST products from OSI SAF, heritage GOES, and Japanese MTSAT.
Using the SQUAM webpage, SST data producers and users can now monitor in NRT various SST products for stability and evolution as well as for cross-product consistency. The presentation will provide an overview of the SQUAM system and its applications and will address any particular interest in the tool for extending it to other applications.
