Mid-latitude tropospheric ozone columns from the MOZAIC program: climatology and interannual variability

[摘要] Several thousands of ozone vertical profiles collected in the course of theMOZAIC programme (Measurements of Ozone, Water Vapour, Carbon Monoxide andNitrogen Oxides by In-Service Airbus Aircraft) from August 1994 to February2002 are investigated to bring out climatological and interannual variabilityaspects. The study is centred on the most frequently visited MOZAIC airports,i.e. Frankfurt (Germany), Paris (France), New York (USA) and the cluster ofTokyo, Nagoya and Osaka (Japan). The analysis focuses on the verticalintegration of ozone from the ground to the dynamical tropopause and thevertical integration of stratospheric-origin ozone throughout thetroposphere. The characteristics of the MOZAIC profiles: frequency offlights, accuracy, precision, and depth of the troposphere observed, arepresented. The climatological analysis shows that the Tropospheric OzoneColumn (TOC) seasonal cycle ranges from a wintertime minimum at all fourstations to a spring-summer maximum in Frankfurt, Paris, and New York. OverJapan, the maximum occurs in spring presumably because of the earlierspringtime sun. The incursion of monsoon air masses into the boundary layerand into the mid troposphere then steeply diminishes the summertime value.Boundary layer contributions to the TOC are 10% higher in New York thanin Frankfurt and Paris during spring and summer, and are 10% higher inJapan than in New York, Frankfurt and Paris during autumn and early spring.Local and remote anthropogenic emissions, and biomass burning over upstreamregions of Asia may be responsible for the larger low- and mid-troposphericcontributions to the tropospheric ozone column over Japan throughout the yearexcept during the summer-monsoon season. A simple Lagrangian analysis hasshown that a minimum of 10% of the TOC is of stratospheric-originthroughout the year. Investigation of the short-term trends of the TOC overthe period 1995–2001 shows a linear increase 0.7%/year in Frankfurt,0.8%/year in Japan, 1.1%/year in New York and 1.6%/year in Paris forthe reduced 1995–1999 period. Dominant ingredients of these positiveshort-term trends are the continuous increase of wintertime troposphericozone columns from 1996 to 1999 and the positive contributions of the midtroposphere whatever the season.

[学科分类] 大气科学