Earth from Space: A virtually cloudless UK   This rare virtually cloud-free image of the UK was acquired during a heat wave on 18 July with the Advanced Along Track Scanning Radiometer (AATSR) sensor onboard ESA’s Envisat satellite.   These side-by-side heat maps, produced from data measured by AATSR's thermal channels, highlight the sharp increases in UK land temperatures. The map on the left was acquired on 15 July 2006 and shows cooler temperatures, while the map on the right shows warmer temperatures on 18 July 2006. The scale ranges from yellow to red, with red indicating higher temperatures. Release date: 2 March 2007