Osservazione della Terra dallo spazio: Risultati scientifici   This image sequence of 13 visible channel images was taken over West Africa and the Eastern Atlantic. One can see large dust clouds travelling westwards out to the Atlantic Ocean. The dust unlike clouds is more fuzzy and has less contrast. This sequence was observed on 9 March 1998. A sequence of thirteen visible images was taken (8.30 Z to 15.00 Z).   ERS-derived images of the volcano Etna in Italy, summer 2001. Using precise techniques known as SAR Interferometry (InSAR), researchers have been able to monitor the movements of Etna for over 10 years including the eruption in 1993. A digital terrain model of the volcano and measurements of geophysical parameters, such as the volcanic mouth deflation, were already generated in 1995 by making use of complex interferometric techniques applied to ERS SAR images. ERS-2 SAR image data were then collected and processed to analyse the 2001 eruption.   Low levels of stratospheric ozone (blue) observed by ERS-2 over Europe in November 1999. Photo: GOME/ERS-2 and KNMI   The height is the sea level anomaly (-40 to +40 cm) measured by the Radar Altimeter and the colour is the sea surface temperature anomaly (-6 to +8 degrees) measured by the Along Track Scanning Radiometer (ATSR). Both of these instruments are also on-board Envisat.   The office for Envisat, the new Earth observation satellite, ESRIN Release date: 10 Maggio 2001