SST Climatology based on 9 years of AVHRR data


In September 2007, OrCOOS was contacted by the US Coast Guard (USCG) and asked to provide them with a 12-month sea-surface temperature (SST) climatology for the Oregon coast. The USCG will use this SST information to determine whether or not to require immersion suits - encapsulating, insulating, waterproof garments used to provide buoyancy and thermal protection in water 59 degrees F or below - and survival craft, as well as what type of survival craft on commercial fishing vessels.

According to the USCG, the regulations for commercial fishing vessels are less restrictive in waters above 59 degrees F (15 degrees C), and inside 20 nautical miles. The USCG defines “Cold Water” as at or below 15 degrees C. Current policy draws a line straight out from Point Reyes, CA. North of this line the water is assumed to be “cold” year round. South of Point Reyes the “Cold Water” line moves up and down the California coast based on the time of year and historical water temperature data. This policy, which was written in 1991 and can be viewed HERE, has been questioned by some Oregon fishermen, who say that at certain times of the year, SST is above 59 degrees F off the Oregon coast. The SST climatology provided by OrCOOS, which is based on about 9 years (1997-2006) of 1 km AVHRR (Advanced Very High Resolution Radiometer) data (Venegas et al., 2007), shows this to be true. During the summer months, July, August and September, SST inside of 20 nautical miles (thick white line), between Lincoln City, OR and the Columbia River is warmer than 59 degrees F (dashed black line).

References

Venegas, R. M., P. T. Strub, E. Beier, R. Letelier, A. C. Thomas, T. Cowles, C. James, L. Soto-Mardones, and C. Cabrera (2008), Satellite-derived variability in chlorophyll, wind stress, sea surface height, and temperature in the northern California Current System, J. Geophys. Res., 113, C03015, doi:10.1029/2007JC004481.

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