Total ozone dependence of the difference between the empirically corrected EP-TOMS and high-latitude station datasets

Abstract

A comparison was made of the ground-based and satellite total ozone content (TOC) measurements in the atmosphere over the Antarctic stations Vernadsky, Halley and Amundsen–Scott and the Arctic station Barrow. A similar discrepancy analysis was performed using the global network of ground-based ozonometric stations from the beginning of regular satellite observations in 1978. Slowing of the long-term global ozone losses has been observed during the past decade and a recovery of the ozone layer is forecast for the coming decades. Therefore, the accuracy requirements for ozone measurements are increasing, which, in turn, requires corresponding analysis of the measurement errors. In this work, the Earth Probe Total Ozone Mapping Spectrometer (EP-TOMS) satellite data from 1996 to 2005 were used. Satellite daily TOC values were taken using version 8 of the algorithm introduced in 2004 and empirically corrected in 2007. The most persistent features of the relative EP-TOMS–Dobson difference are: (1) a significant increase in dispersion during the period of the spring Antarctic ozone hole and (2) a differing dependence on total ozone in the trend tendency and significance for EP-TOMS and Dobson datasets. The results indicate the influence of the specific conditions during the Antarctic ozone hole on the possible precision that could be achieved in assessments of Montreal Protocol effects in the ozone layer over this region.

Acknowledgements

Earth Probe TOMS daily total ozone data were provided by the Ozone Processing Team, NASA Goddard Space Flight Center, USA, from their website at http://toms.gsfc.nasa.gov/eptoms/ep_v8.html. Ground-based daily total ozone data were provided by the British Antarctic Survey, UK (www.antarctica.ac.uk/met/jds/ozone) and the Global Monitoring Division, NOAA Earth System Research Laboratory, USA (www.esrl.noaa.gov/gmd/ozwv/dobson). This work was partly supported by the National Taras Shevchenko University of Kyiv, project 06BF051-12, and was partly undertaken in the framework of the ORACLE-O3 IPY project. We thank two anonymous referees for their useful comments.