Understanding differences in chemistry climate model projections of stratospheric ozone

摘要: Chemistry climate models (CCMs) are used to project future evolution of stratospheric ozone as concentrations ozone-depleting substances (ODSs) decrease and greenhouse gases increase, cooling the stratosphere. CCM projections exhibit not only many common features but also a broad range values for quantities such year return 1980 global level at end 21st century. Multiple linear regression is applied each 14 CCMs separate response ODS concentration change from that due change. We show sensitivity lower chlorine ΔO3/ΔCly near-linear function partitioning total inorganic (Cly) into its reservoirs; both Cly largely controlled by transport. with best performance on transport diagnostics agree observations reservoirs produce similar responses After 2035, differences in contribute little spread anthropogenic contribution becomes unimportant. Differences among upper increases temperature decreases explained ΔO3/ΔT different contributions various loss processes, own dependence. Ozone tropical stratosphere caused projected speedup Brewer-Dobson circulation may or be balanced middle- high-latitude troposphere. This balance, lack thereof, contributes most late century projections.