HR: 09:45h
AN: A11D-08    [PDF]
TI: Future Changes in Stratosphere-Troposphere Exchange and Those Impacts on Future Tropospheric Ozone
AU: * Sudo, K
EM: kengo@jamstec.go.jp
AF: Frontier Research System for Global Change (FRSGC), 3173-25 Showa-machi Kanazawa-ku,, Yokohama, 236-0001 Japan
AU: Takahashi, M
EM: masaaki@ccsr.u-tokyo.ac.jp
AF: Center for Climate System Research (CCSR), University of Tokyo., 4-6-1, Komaba, Meguro-ku,, Tokyo, 153-8904 Japan
AU: Akimoto, H
EM: akimoto@jamstec.go.jp
AF: Frontier Research System for Global Change (FRSGC), 3173-25 Showa-machi Kanazawa-ku,, Yokohama, 236-0001 Japan
AB: We assess future climate change impacts on stratosphere-troposphere exchange (STE) and those influences on tropospheric ${\rm O_3}$, using a chemistry coupled climate model. This study employs the coupled tropospheric chemistry climate model CHASER which has been developed in the framework of the Center for Climate System Research/National Institute for Environment Studies (CCSR/NIES) GCM. Tropospheric ${\rm O_3}$ distribution and budget were predicted decadally for 1990 to 2100 with emission changes (for ${\rm O_3}$ precursors) and climate change specified by the IPCC SRES-A2 scenario. Our simulations show increases in stratospheric ${\rm O_3}$ transport to the troposphere as a result of enhancement in the tropospheric (the Hadley) and stratospheric (the Brewer-Dobson) circulation with climate change in the model. With emission changes only, net stratospheric ${\rm O_3}$ input to the troposphere were simulated to decrease by $\sim$20% during 1990-2100 in response to the simulated tropospheric ${\rm O_3}$ increases, but to increase by more than 80% with including climate change also (600Tg${\rm O_3}$/yr in 1990 to $\sim$1100Tg${\rm O_3}$/yr in 2100). The enhanced STE with climate change has larger impacts on tropospheric ${\rm O_3}$ distribution in the southern hemisphere than in the northern hemisphere, because of shorter chemical lifetime of ${\rm O_3}$ and larger water vapor increases in the northern hemisphere. Simulated increases in net cross-tropopause ${\rm O_3}$ transport are most significant particularly after 2050 reflecting the climate sensitivity of the CCSR/NIES GCM. Our simulations of atmospheric radon also suggest enhancement in stratosphere-troposphere mixing with future climate change.
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting