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TES thermal IR satellite observations for 2006, seasonal means at 500 hPa. Maximum values at northern mid-latitudes in spring-summer due to anthropogenic pollution; High values in tropical regions affected by seasonal biomass burning; Minimum values over tropical oceans due to chemical loss . - PowerPoint PPT Presentation
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GLOBAL DISTRIBUTION OF TROPOSPHERIC OZONE
Zhang et al. [2010]
TES thermal IR satellite observations for 2006, seasonal means at 500 hPa
• Maximum values at northern mid-latitudes in spring-summer due to anthropogenic pollution;
• High values in tropical regions affected by seasonal biomass burning;
• Minimum values over tropical oceans due to chemical loss
OBSERVED RISE IN TROPOSPHERIC OZONEOBSERVED RISE IN TROPOSPHERIC OZONEOVER 20OVER 20thth CENTURY CENTURY
Preindustrialozone models
}Observations at mountain sites in Europe [Marenco et al., 1994]
Models underestimate the observed trend
RADIATIVE FORCING BY TROPOSPHERIC OZONE RADIATIVE FORCING BY TROPOSPHERIC OZONE COULD BE MUCH LARGER THAN IPCC VALUECOULD BE MUCH LARGER THAN IPCC VALUE
Standard model:
F = 0.44 W m-2
“Adjusted” model
(lightning and soil NOx decreased,
biogenic hydrocarbons increased):
F = 0.80 W m-2
Global simulation of late 19th century ozone observations [Mickley et al., 2001]
GLOBAL OZONE AND OH TRENDSMean mass-weighted tropospheric values computed from GEOS-Chem model
for present-day (PD), pre-industrial (PI), and last glacial maximum (LGM)
Ozone, ppb
OH, 105 molecules cm-3
PD PI LGMtwo different climatereconstructionsLee Murray, Harvard
MODEL INTERCOMPARISON OF OH TRENDSMODEL INTERCOMPARISON OF OH TRENDS
LGM to pre-industrial Pre-industrial to present
TRENDS IN GLOBALTROPOSPHERIC OHinferred from methylchloroform observations
IPCC, 2007
Montzka et al., 2011