Multimodel projections of stratospheric ozone in the 21st century

摘要: [1] Simulations from eleven coupled chemistry-climate models (CCMs) employing nearly identical forcings have been used to project the evolution of stratospheric ozone throughout 21st century. The model-to-model agreement in projected temperature trends is good, and all CCMs predict continued, global mean cooling stratosphere over next 5 decades, increasing around 0.25 K/decade at 50 hPa 1 K/ decade under Intergovernmental Panel on Climate Change (IPCC) Special Report Emissions Scenarios (SRES) A1B scenario. In general, simulated mainly determined by decreases halogen concentrations continued due increases greenhouse gases (GHGs). Column increase as return 1980s levels. Because middle upper GHGinduced cooling, total averaged midlatitudes, outside polar regions, globally, 1980 values between 2035 2050 before lowerstratospheric amounts decrease values. regions simulate small first second half century midwinter. Differences inorganic chlorine (Cly) among are key diagnosing intermodel differences recovery, particular Antarctic. It found that there substantial quantitative Cly, with October Antarctic Cly peak value varying less than 2 ppb 3.5 CCMs, date which returns 2030 after 2050. There a similar variation timing recovery springtime column back As most underestimate Clynear 2000, could occur even later, 2060 2070. Arctic spring does not follow closely Antarctic, reaching