The combined record of total andprofile ozone measurements from the solar backscatter ultraviolet (SBUV) andSBUV/2 series of instruments, known as the SBUV Merged Ozone Data (MOD)product, constitutes the longest satellite-based ozone time series from asingle instrument type and as such plays a key role in ozone trend analyses.Following the approach documented in Frith et al. (2014) to analyze themerging uncertainties in the MOD total ozone record, we use Monte Carlosimulations to estimate the potential for uncertainties in the calibrationand drift of individual instruments in the profile ozone merged data set. Wefocus our discussion on the trends and associated merging uncertainty since2001 in an effort to verify the start of ozone recovery as predicted bychemistry climate models. We find that merging uncertainty dominates theoverall estimated uncertainty when considering only the 15 years of datasince 2001. We derive trends versus pressure level for the MOD data set thatare positive in the upper stratosphere as expected for ozone recovery. Thesetrends appear to be significant when only statistical uncertainties areincluded but become not significant at the 2 level when instrumentuncertainties are accounted for. However, when we use the entire data setfrom 1979 through 2015 and fit to the EESC (equivalent effectivestratospheric chlorine) we find statistically significant fits throughoutthe upper stratosphere at all latitudes. This implies that the ozone profiledata remain consistent with our expectation that chlorine is the dominantozone forcing term.
展开▼
