In the past several decades, the tropospheric westerly winds in the Southern Hemisphere have been observed to accelerate on the poleward side of the surface wind maximum. This has been attributed to the combined anthropogenic effects of increasing greenhouse gases and decreasing stratospheric ozone and is predicted to continue by the Intergovernmental Panel on Climate Change/Fourth Assessment R...

The global budget of tropospheric ozone is governed by a complicated ensemble of coupled chemical and dynamical processes. Simulation of tropospheric ozone has been a major focus of the GEOS-Chem chemical transport model (CTM) over the past 20 years, and many developments over the years have affected the model representation of the ozone budget. Here we conduct a comprehensive evaluation of the...

Nitrogen oxides (NOx, the collective name for NO and NO2) play an important role in atmospheric chemistry and in the climate system as precursor of tropospheric ozone, an important greenhouse gas. The most important source of NOx is the combustion of fossil fuels, mainly by traffic and large power plants. Other important contributors are the burning of biomass, soil emissions and lightning. Clo...

The interrelated geographic and temporal variability seen in more than seven years of tropical and subtropical upper tropospheric (215 hPa) ozone, carbon monoxide and cloud ice water content (IWC) observations by the Aura Microwave Limb Sounder (MLS) are presented. Observed ozone abundances and their variability (geographic and temporal) agree to within 10–15 ppbv with records from sonde observ...

Carbon dioxide currently accounts for about 49 percent of the radiative forcing of the atmosphere that is attributable to greenhouse gases (3.0 watts per square meter [W m-2]; Houghton et al. 2001). Tropospheric ozone and black carbon are responsible for another 18 percent, and the well-mixed greenhouse gases (GHGs)—principally methane, nitrous oxide, and various halocarbons—are responsible for...

[1] We assimilate ozone and CO retrievals from the Tropospheric Emission Spectrometer (TES) for July and August 2006 into the GEOS-Chem and AM2-Chem models. We show that the spatiotemporal sampling of the TES measurements is sufficient to constrain the tropospheric ozone distribution in the models despite their different chemical and transport mechanisms. Assimilation of TES data reduces the me...

In this paper, simplified ozone models for potential use in integrated assessment are developed from the EMEP ozone model, which is a single-layer Lagrangian trajectory model. The simplification method uses fuzzy rule generation methodology to represent numerous results of the EMEP model as a response surface describing the source-receptor relationships between ozone precursor emissions and dai...

Improved estimates of the radiative forcing from tropospheric ozone increases since the preindustrial have been calculated with the tropospheric chemistry model used at the Goddard Institute for Space Studies (GISS) within the GISS general circulation model (GCM). The chemistry in this model has been expanded to include simplified representations of peroxyacetylnitrates and non-methane hydrocar...

In this paper we discuss the design, implementation and performance of two neural network algorithms, one for ozone concentration profile, and the second for tropospheric ozone column retrieval from ESA-Envisat SCIAMACHY Level 1b data. The performances of the two algorithms were checked through tests against ozone sondes measurements. Both algorithms make use of visible radiation whose role has...

[1] We characterize the horizontal and vertical distribution of tropospheric ozone measured by the Tropospheric Emission Spectrometer (TES) over North Africa, the Middle East, and Asia. Studies have shown that the summertime circulation associated with the Asian monsoon significantly influences the spatial distribution of ozone and its precursors. However, there have been limited observations o...