Italy’s Po River seen thinning from orbit   A wipe between two ERS SAR images acquired 30 June and 19 July 2003. Within twenty days we can see the Po has thinned somewhat - particularly noticeable on the far right.   This multitemporal picture of a wide expanse of the Po River Valley is a combination of two images acquired on 30 June and 19 July 2003. Where the data input is similar for the two images a yellow-light green is produced. Where red is dominant denotes greater signal return for the June image, and in turn green for the July image. Used in this way, multitemporal images help identify changes in a landscape. Release date: 28 June 2004