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 will have a resolution of 10km and be produced twice daily at 00 UTC and 12 UTC. It will cover the Atlantic Ocean from 50N to 90N. Polar orbiting satellites with the AVHRR instrument will be used for this product. In the development fase the two NOAA satellites NOAA-14 and NOAA-15 will be used. Later the METOP satellites and next NOAA satellites will also be used. The developed method will also be tested to produce a SST product for the South Atlantic Ocean south of 50S.

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 (mainly Pathfinder). For high latitudes a non-linear algorithm has been selected, and it has this formulation:

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

where A,B₀,B₁,B₂,C₀ and C₁ are constants, S = sec(satellite zenith angle), T_guess 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

Images with examples of the High Latitude SST from part of the area to be covered by the product.

Colour palette for SST images:
Light grey	clouds
White	sea ice
Dark grey	land

Example from 23.02.2005

Point of contact

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