The balance of effects of deep convective mixing on tropospheric ozone

[1] The balance of effects that vertical transport associated with deep cumulus convection has on tropospheric O3 is discussed. We first show theoretically that convective mixing of O3 can substantially reduce its column mean lifetime over clean regions, while a much smaller increase is generally expected over polluted regions. The global chemistry-transport model MATCH-MPIC confirms this, computing a 6% decrease in the annual mean tropospheric O3 burden and a 7% decrease in its lifetime due to convective transport of O3 alone. We find, however, that the net effect of convective transport of all trace gases (O3 and precursors together) is a 12% increase in the tropospheric O3 burden. Thus, in contrast to previous literature, our results indicate that the enhanced O3 production due to precursor transport from polluted regions significantly outweighs the reduction in O3 lifetime due to mixing over clean regions.

[1]  T. Nordmeyer,et al.  Heterogeneous chemistry in the troposphere: experimental approaches and applications to the chemistry of sea salt particles , 1999 .

[2]  V. Ramanathan,et al.  Observations of Near-Zero Ozone Concentrations Over the Convective Pacific: Effects on Air Chemistry , 1996, Science.

[3]  J. Hack.  Parameterization of moist convection in the National Center for Atmospheric Research community climate model (CCM2) , 1994 .

[4]  P. Crutzen,et al.  Rarity of upper-tropospheric low O 3 concentration events during MOZAIC flights , 2003 .

[5]  R. Dickerson,et al.  Thunderstorms: An Important Mechanism in the Transport of Air Pollutants , 1987, Science.

[6]  Mark Lawrence,et al.  Global chemical weather forecasts for field campaign planning: predictions and observations of large-scale features during MINOS, CONTRACE, and INDOEX , 2002 .

[7]  Philip J. Rasch,et al.  Representations of transport, convection, and the hydrologic cycle in chemical transport models : Implications for the modeling of short-lived and soluble species , 1997 .

[8]  H. Levy,et al.  A model analysis of the tropical South Atlantic Ocean tropospheric ozone maximum: The interaction of transport and chemistry , 2000 .

[9]  J. Lelieveld,et al.  Role of Deep Cloud Convection in the Ozone Budget of the Troposphere , 1994, Science.

[10]  Mark Lawrence,et al.  A model for studies of tropospheric photochemistry: Description, global distributions, and evaluation , 1999 .

[11]  N. McFarlane,et al.  Sensitivity of Climate Simulations to the Parameterization of Cumulus Convection in the Canadian Climate Centre General Circulation Model , 1995, Data, Models and Analysis.

[12]  R. Dickerson,et al.  Model calculations of tropospheric ozone production potential following observed convective events , 1990 .

[13]  Paul J. Crutzen,et al.  A model for studies of tropospheric ozone and nonmethane hydrocarbons: Model description and ozone results , 2003 .