Open AccessGlobal validation of empirically corrected EP‐Total Ozone Mapping Spectrometer (TOMS) total ozone columns using Brewer and Dobson ground‐based measurements
Author(s) -
Antón M.,
Koukouli M. E.,
Kroon M.,
McPeters R. D.,
Labow G. J.,
Balis D.,
Serrano A.
Publication year - 2010
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010jd014178
Subject(s) - total ozone mapping spectrometer , satellite , environmental science , ozone , atmospheric sciences , solar zenith angle , latitude , meteorology , ozone layer , physics , astronomy
This article focuses on the global‐scale validation of the empirically corrected Version 8 total ozone column data set acquired by the NASA Total Ozone Mapping Spectrometer (TOMS) during the period 1996–2004 when this instrument was flying aboard the Earth Probe (EP) satellite platform. This analysis is based on the use of spatially co‐located, ground‐based measurements from Dobson and Brewer spectrophotometers. The original EP‐TOMS V8 total ozone column data set was also validated with these ground‐based measurements to quantify the improvements made by the empirical correction that was necessary as a result of instrumental degradation issues occurring from the year 2000 onward that were uncorrectable by normal calibration techniques. EP‐TOMS V8‐corrected total ozone data present a remarkable improvement concerning the significant negative bias of around ∼3% detected in the original EP‐TOMS V8 observations after the year 2000. Neither the original nor the corrected EP‐TOMS satellite total ozone data sets show a significant dependence on latitude. In addition, both EP‐TOMS satellite data sets overestimate the Brewer measurements for small solar zenith angles (SZA) and underestimate for large SZA, explaining a significant seasonality (∼1.5%) for cloud‐free and cloudy conditions. Conversely, relative differences between EP‐TOMS and Dobson present almost no dependence on SZA for cloud‐free conditions and a strong dependence for cloudy conditions (from +2% for small SZA to −1% for high SZA). The dependence of the satellite ground‐based relative differences on total ozone shows good agreement for column values above 250 Dobson units. Our main conclusion is that the upgrade to TOMS V8‐corrected total ozone data presents a remarkable improvement. Nevertheless, despite its quality, the EP‐TOMS data for the period 2000–2004 should not be used as a source for trend analysis since EP‐TOMS ozone trends are empirically corrected using NOAA‐16 and NOAA‐17 solar backscatter ultraviolet/2 data as external references, and therefore, they are no longer considered as independent observations.