The data come from Envisat's Advanced Along Track Radiometer (AATSR), which functions like a space-based thermometer. The instrument records infrared wavelengths of light to calculate sea surface temperature to an accuracy of 0.3 degrees and a spatial resolution of 1 sq km. The images were prepared for ESA by the Rutherford Appleton Laboratory.
"The difference between the two years is a striking demonstration of how variable the climate can be," said Professor David Llewellyn-Jones of University of Leicester, the Principal Investigator for AATSR. "Sea surface temperature is an especially important factor in climate studies because it takes a long time and the transfer of a lot of heat to change it.
"The oceans actually represent an enormous reservoir of heat. It's not generally realised but they absorb directly the majority of energy radiated from the Sun due to their surface area covering about 71 per cent of the Earth's surface. The oceans then transfer heat directly to the atmosphere."
The oceans are a good indicator of possible climate change because they actually store a huge amount of solar heat, and their temperatures are an indication of how much heat they hold. They take much longer to warm up or cool down by comparison to the land or the air, so sea surface temperature records can be used to help identify longer-term climatic trends.
"By themselves, these particular AATSR images just show us is that the climate varies and that
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Contact: Henri Laur
henri.laur@esa.int
39-06-941-80-557
European Space Agency
24-Sep-2003