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Sea Surface Temperature product

For more detailed information, have a look at the Product User Manual under Documents.

The high latitude Sea Surface Temperature (SST) product is developed at met.no in cooperation with DMI. At Météo France an equivalent product is developed for low and mid latitudes. These two products will be used to make the Merged Atlantic Product which will cover the Atlantic Ocean from 60S to 90N.

The high latitude SST product has a resolution of 5km and is produced twice daily at 00 UTC and 12 UTC. It cover the Atlantic Ocean from 50N to 90N. Polar orbiting satellites with the AVHRR instrument are used for this product. The EUMETSAT METOP-A satellite and NOAA satellites NOAA-18 and NOAA-19 are currently used.

The production scheme will have the following steps:

  • Satellite retrieval and preprocessing.
  • Cloud masking (developed by the SMHI, see this site for more info).
  • SST calculations.
  • Control of SST using climatology.

The SST algorithm

The SST algorithm has been developed by using radiative simulations. The simulations have been performed using the radiative transfer model MODTRAN. For these simulations several cloud free radiosoundings have been used to cover the cloud free atmospheric conditions at high latitudes. Several algorithm formalisms have been tested using matchup databases. For high latitudes a non-linear algorithm with the following formulation has been selected:

SST = A*T4 + (B0 + B1*S + B2*Tguess)*(T4-T5) + C0 + C1*S

where A,B0,B1,B2,C0 and C1 are constants, S = sec(satellite zenith angle), Tguess is a first guess SST (ie. climatology), and T4 and T5 are the AVHRR channel 4 and 5 brightness temperatures.
This gives the skin SST. A bias correction method will be used to provide the bulk SST.

The algorithm coefficients

The coefficients currently and previously used can be found at this page.

Product example

The image below shows an example of the 12 hourly SST field from 08.10.2014 00:00UTC. Cloudy areas are shown in light grey, sea ice in white and land areas in dark grey.

Point of contact

Contact person for OSI SAF High Latitude SST products is Steinar Eastwood, met.no, osisaf-manager[at]met.no.