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Conclusions

We describe in this work the results obtained when TOMS/EP satellite ozone data are intercompared with other satellite and ground based data. The mean relative difference between both TOMS, one on board of ADEOS (NASDA) and the other one on EP (NASA) is within 1 %, for the Southern Cone of South America and Antarctic continent region (30º - 90º S, 30º - 90º W). However, the TOMS/EP-ground intercomparison shows an increase as function of latitude, with a mean systematic difference of (5 ± 2.3) % for all the region and period. The GOME/ERS-2-ground intercomparison gives a lower mean difference of (-1.4 ± 3.2) %.

Different tests have been done in order to elucidates the rather large TOMS-ground difference, like: intercomparison of two TOMS measuring at the same time and place and on board of two satellites at different orbits (and consequently different pixel resolution); comparison with other satellite instrument (GOME/ERS-2) measuring the same geophysical variable; analysis of the possible effect due to the difference in UV reflectivity at the ice (snow)-sea boundary on satellite data.

New insight appears from the present intercomparisons and future work will be done in order to try to determine the actual source (or sources) of the systematic difference between TOMS/EP and ground based spectroradiometers, which influence, besides other related subjects: The definition of the extension and depth of the Antarctic ozone hole, the model description of the UVB radiation and solar risk over the Southern Cone of South America (the most influenced large-inhabited region by the ozone depletion) and the “in situ” calibration of ground based instruments used in different institutions, with respect to the satellite one.

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