Global tropospheric ozone variations from 2003 to 2011 as seen by SCIAMACHY

An analysis of the tropospheric ozone (O.sub.3) columns (TOCs) derived from SCIAMACHY limb-nadir-matching (LNM) observations during the period 2003-2011, focusing on global variations in TOC, is described. The changes are derived using a multivariate linear regression model. TOC shows changes of -0.2 ± 0.4, 0.3 ± 0.4, 0.1 ± 0.5 and 0.1 ± 0.2 % yr.sup.-1, which are not statistically significant at the 2σ level in the latitude bands 30-50°â€¯N, 20°â€¯S-0, 0-20°â€¯N and 50-30°â€¯S, respectively. Tropospheric O.sub.3 shows statistically significant increases over some regions of South Asia (1-3 % yr.sup.-1 ), the South American continent (up to 2 % yr.sup.-1 ), Alaska (up to 2 % yr.sup.-1) and around Congo in Africa (up to 2 % yr.sup.-1). Significant increase in TOC is determined off the continents including Australia (up to 2 % yr.sup.-1 ), Eurasia (1-3 % yr.sup.-1) and South America (up to 3 % yr.sup.-1). Significant decrease in TOC (up to -3 % yr.sup.-1) is observed over some regions of the continents of North America, Europe and South America. Over the oceanic regions including the Pacific, North Atlantic and Indian oceans, significant decreases in TOC (-1 to -3 % yr.sup.-1) were observed. In addition, the response of the El Niño-Southern Oscillation (ENSO) and quasi-biennial oscillation (QBO) to changes in TOC for the period 2003-2011 was investigated. The result shows extensive regions, mostly in the tropics and Northern Hemisphere extratropics, of significant ENSO responses to changes in TOC and a significant QBO response to TOC changes over some regions.