Stratospheric ozone transboundary transport to upper troposphere North Africa

Abstract

Stratosphere-troposphere exchange (STE) influences the chemical composition of both the stratosphere and the troposphere and represents an important aspect of global change [Butchart and Scaife, 2001]. It is also often associated with severe weather events [Goering et al., 2001]. Upper tropospheric ozone is an important greenhouse gas that affects global outgoing long wave radiations, chemistry, climate, and the radiation budget [Holton et al. 1995]. Their changes have a great impact on the surface temperature [Forster and Shine, 1997]. The Measurements of Ozone by Airbus In service airCraft (MOZAIC) program was designed to collect ozone and water vapor data using automatic equipment installed on board five long-range Airbus A340 aircraft flying regularly all over the world [Marenco et al., 1998]. The overall objective of the programme is to improve our physical and chemical understanding of the atmosphere. According to Danielsen [1982] air in the stratosphere has high static stability and, as a result, high IPV values greater than 1.5 IPV units (1.5 X 10-6 K kg -1 m 2s-1) are typically found only in the stratosphere; thus IPV can also be used to trace ozone-rich air which has moved from the stratosphere to the troposphere. This work will identify the causes and sources of MOZAIC ozone enhancements at upper tropospheric North Africa (20-350 N). In addition the paper will address the modes of transport of ozone rich airmass sampled by MOZAIC at mid latitude and North Africa.