ERS-2 result : GOME total ozone column Monthly mean

Total column ozone distribution over the Earth's south pole derived from measurements by the Global Ozone Monitoring Experiment (GOME) instrument onboard ESA's ERS-2 (European Remote Sensing) satellite. GOME, which was flown only on ERS-2, was designed to track ozone and trace gases in the troposphere and stratosphere. The GOME measurements have been daily available since June 1995 and are processed and assimilated to global maps by DLR in near-real-time. The total column ozone is depicted in Dobson Units. A level of 300 Dobson Units is the global mean and equals a thickness of the ozone layer of 3 mm. While the areas in yellow and green indicate normal levels, the red color shows higher concentrations (up to 500 units). The areas in dark blue and purple indicate the "hole" in the ozone layer, with concentration levels below 180 units. Designed as forerunners for future environmental monitoring platforms, the two ERS satellites were the first pre-operational civilian remote sensing satellite able to collect imagery whatever the lightning and cloud conditions. The two spacecraft were designed and built by an industrial team led by Dornier of Germany. They reused the same satellite bus developed by Matra for the French Spot optical remote sensing satellites. Each 2.4-ton spacecraft carries an Active Microwave instrument incorporating two high power radars: a Synthetic Aperture Radar (SAR) with a 10-m antenna for image and wave modes, and a 3-beam scatterometer for the wind mode. SAR imaging achieves a 30-m ground resolution. Other major instruments are the Radar Altimeter (RA), to measure the wave heights and altitude as well as the ice sheet topography, and the Along-Track Scanning Radiometer and Microwave Sounder (ATSR-M), to measure temperatures and water vapor concentrations with applications ranging from vegetation moisture determination to collection of corrective data for RA. Two other payloads, PRARE and a laser reflector, provide fine orbit determination for RA calibration. ERS-1 was launched by an Ariane 4 on July 17, 1991, and placed onto a Sun-synchronous orbit at an altitude of 785 km, which enabled to repeat ground tracks after 35 days. ERS-2 followed on April 21, 1995, also on an Ariane 4. It was released on the same orbit and was phased just one day after ERS-1. Although designed for a 3-year lifetime, ERS-1 performed for almost 9 years and ERS-2 was still operational, although in gyroless mode, after 8 years. Their successor, the Envisat polar platform, was launched on February 28, 2002.