Both TOMS ( Total Ozone Mapping Spectrometer ) and UARS ( Upper Atmosphere Research Satellite ) have operated over an extended period , and generated data sets of sufficient accuracy to be of use in determining ozone change ( TOMS ) and some of the underlying causes ( UARS ) . The basic scientific products have been used for model validation and assimilation to extend our understanding of stratospheric processes . TOMS on Nimbus-7 , Earth - Probe , and QuikTOMS , and UARS have led to the next generation of instruments onboard the EOS platforms . Algorithms used for TOMS and UARS are being applied to the new data sets and extended to analysis of European satellite data ( e.g. , GOME )