Envisat’s Advanced Along Track Scanning Radiometer (AATSR) instrument, which measures global sea-surface temperature (SST) to an accuracy of 0.2ºC, dramatically illustrates the complexity of the thermal currents at play in the Southern Mediterranean off the coast of Northern Libya. The brightest pale blue colour represents the warmest temperatures of approximately 25ºC, while the darkest blue colour represents cooler temperatures of around 21ºC. Image acquired on 18 September 2007.