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Sea Surface Temperature

Description:

The "Sea Surface Temperature derived from NOAA-AVHRR data (SST_AVHRR)" are three grid maps for the Western Atlantic (2500 lines/ 3900 samples), Mediterranen Sea (2048 lines / 4096 samples) and the Madeira area (2200 lines / 1350 samples) in Mercator projection with the earth radius of 6378.137 km (no geoid, no ellipsoid!). All maps have a spatial resolution of about 1.1 km at the center of the satellite map. All MCSST data are transformed to the fixed grid projection by resampling and interpolation the dataset on a pixel by pixel basis. The simplest nearest neighbor algorithm is used. Within 24 hours of acquiring data from the satellite, SSTs are calculated. In general, the products utilise data from all six of the passes that the satellite makes over Europe in each 24 hour period. The SST maps are composed according the maximum temperature value given at every pixel's position to minimize cloud coverage. Weekly and monthly products are derived from the daily maximum images using the average at every pixel's position.
The range of SST values is scaled between 0.125°C and 31.75°C (maximum temperature). The radiometric resolution is 0.125°C. Land is black and clouds (or no data) are white.

Product Example:

Sea Surface Temperature
Region: Mediterranean Sea MCSST, Region: MEDITERRANEAN 1-Week Composite 23.01.2012 - 29.01.2012
Land is masked black, clouds are white

Methodology:

The operational production chain was launched in March 1993 covering the entire Mediterranean Sea and the Black Sea. Since then, daily, weekly, and monthly data sets have been available. The product is intended for climate modelers, oceanographers, and all geo science-related disciplines dealing with ocean surface parameters. In addition, SST maps covering the North Atlantic, the Baltic Sea, the North Sea and the Western Atlantic equivalent to the Mediterranean MCSST maps are available since August 1994. The most important aspects of the MCSST maps are a) correct image registration and b) reasonable cloud screening to ensure that only cloud free pixels are taken for the later processing of composition.

The applied formula for deriving SST is based on the brightness temperatures of AVHRR channels 4 and 5 (T4 T5) and is described by McCLAIN et al. (1985). This technique is known as the "Split Window Technique" and corrects atmospheric attenuation mainly caused by absorption of water vapor in the atmosphere, which normally leads to a significant drop in derived brightness temperatures, depending on the region down to 8 degrees Celsius.

Major users:

Scientific Organisations

Publications:

Dech, S., Tungalagsaikhan, P., Preusser, C., & Meisner, R., 1998. Operational value-adding to AVHRR data over Europe: methods, results, and prospects. Aerospace Science and Technology, 5, 335-346.

Relevance:

Sea surface temperature (SST) is an important factor controlling most physical, chemical, and biological processes of the oceans.

Data Access

Access to AVHRR Nighttime Weekly and Monthly Global MCSST Data

Contact: Dr. Kurt P. Günther