NOAA has been producing sea surface temperatures (SSTs) from satellite data since 1972.  Monitoring of sea surface temperature (SST) from earth-orbiting infrared radiometers has had a wide impact on oceanographic science.  Currently, one of the principal sources of infrared data for SST measurement is from the Advanced Very High Resolution Radiometer (AVHRR) carried on NOAA's Polar Orbiting Environmental Satellites (POES), beginning in 1978.  AVHRR is a broad-band, four or five channel (depending on the model) scanner, sensing in the visible, near-infrared, and thermal infrared portions of the electromagnetic spectrum.  The POES satellite system offers the advantage of daily global coverage, by making near-polar orbits roughly 14.1 times daily.  In-situ SSTs, from buoys (drifting and moored) are used operationally to maintain accuracy -- removing any biases, and compiling statistics with time (1,2,3).

The chart shown at the top of this page is the graphic display of the most recent satellite global nighttime composite AVHRR-SSTs at 50km resolution produced twice-weekly in near real-time fashion.  Starting May 3 2007, the near real-time SST data and chart are produced twice-weekly during the mornings (U.S. Eastern Time) of every Monday (using AVHRR data from the previous Thursday through Sunday) and Thursday (using AVHRR data from the previous Monday through Wednesday).  Previously, the SST data and chart were produced twice-weekly on every Tuesday (using AVHRR data from the previous Saturday through Monday) and Saturday (using AVHRR data from the previous Tuesday through Friday).  Nighttime SST observations have been used for producing our coral reef products (see below) to eliminate the diurnal variation caused by diurnal solar heating at the sea surface (primarily at the "skin" interface, 10-20 µm).  A more conservative prediction can be made from nighttime SST observations.  NOAA's operational SSTs use both day and night retrievals, but nighttime SSTs compare favorably with in-situ SSTs at 1 meter depths (4).

The AVHRR-SST products were primarily developed for NOAA's Coral Reef Watch (CRW) Program from satellite data for both monitoring and assessment of coral bleaching.  CRW's other satellite monitoring and assessment products include the SST anomalies, coral bleaching HotSpots, Degree Heating Weeks, Tropical Coral Bleaching Indices, and SST time series.

A coral reef team of the NOAA National Environmental Satellite, Data, and Information Service (NESDIS) generates these coral reef bleaching monitoring products.  The NESDIS team comprises scientists from the Marine Ecosystems Branch (MEB) in the Satellite Oceanography and Climatology Division (SOCD) of Center for Satellite Applications and Research (STAR) and from the Product Systems Branch (PSB) of the Information Processing Division (IPD) of the Office of Satellite Data Processing and Distribution (OSDPD).

References

(1) McClain, E.P. et al., 1985: Comparative performance of AVHRR-based multi channel sea surface temperatures; J. Geophys. Res., 90, 11,587.

(2) Strong, A.E., 1991: Sea surface temperature signals from space. In: Encyclopedia of Earth System Science, Ed. W.A. Nierenberg, Vol 4, Academic Press, San Diego, CA, pp 69-80.

(3) Strong, A. E., E. Kearns, and K. K. Gjovig, 2000: Sea Surface Temperature Signals from Satellites - An Update. Geophys. Res. Lett, 27(11): 1667-1670 (June 1, 2000).

(4) Montgomery, R. S., and A. E. Strong, 1995: Coral Bleaching threatens oceans, life. Eos, Transactions, American Geophysical Union, 75, 145-147.