Recent model calculations of the global mean radiative forcing from tropospheric ozone since preindustrial times fall in a relatively narrow range, from 0.3 to 0.5 W m . These calculations use preindustrial ozone elds that overestimate observations available from the turn of the nineteenth century. Although there may be calibration problems with the observations, uncertainties in model estimate...

We use a three-dimensional chemical transport model to examine the shortwave radiative effects of clouds on the tropospheric ozone budget. In addition to looking at changes in global concentrations as previous studies have done, we examine changes in ozone chemical production and loss caused by clouds and how these vary in different parts of the troposphere. On a global scale, we find that clou...

to 100 DU or even less. Such severe depletion was not observed in the Arctic. Judged by these criteria, there was no Arctic ozone hole in 2011 — only the most extreme episode of ozone loss seen in the Arctic so far. However, the evolution of HNO3, HCl and ClO species was strikingly Antarctic-like and different from what has been observed in other Arctic winters. On the basis of these considerat...

This paper examines the effects of soil moisture initialization in a coupled air quality–meteorological model on temperature profiles, wind speeds, and pollutant concentrations. Three simulations, each with different initial soil moisture fields, were run. In the baseline simulation, predicted temperatures, wind speeds, and gas/aerosol pollutant concentrations accurately matched observations. I...

Accurate representation of ozone in the extratropical upper troposphere (UT) remains a challenge. However, the implementation of hyper-spectral remote sensing using satellite instruments such as the Tropospheric Emission Spectrometer (TES) provides an avenue for mapping ozone in this region, from 500 to 300 hPa. As a polar orbiting satellite TES observations are limited, but in this paper they ...

Key findings !" Atmospheric concentrations of ozone depleting substances have decreased as a result of the effectiveness of the Montreal Protocol. !" The global (60°S–60°N) ozone concentration is projected to return to pre-1980 levels by around the middle of the 21st century. !" Antarctic ozone levels are projected to return to pre-1980 levels around 2060–75, which is 10–25 years later than pre...

We present the chemistry-climate model UM CAM in which a relatively detailed tropospheric chemical module has been incorporated into the UK Met Office’s Unified Model version 4.5. We obtain good agreements between the modelled ozone/nitrogen species and a range of observations including surface ozone measurements, ozone sonde data, and some aircraft campaigns. Four 2100 calculations assess mode...

Abstract. The total ozone data over Europe are available for only few ground-based stations in the pre-satellite era disallowing examination of the spatial trend variability over the whole continent. A need of having gridded ozone data for a trend analysis and input to radiative transfer models stimulated a reconstruction of the daily ozone values since January 1950. Description of the reconstr...

[1] We examine the ozone production efficiency in transpacific Asian pollution plumes, and the implications for ozone air quality in California, by using aircraft and surface observations in April–May 2002 from the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) campaign off the California coast and the Pacific Exploration of Asian Continental Emission–B (PEACE-B) campaig...

Although ultraviolet radiation (400–280 nm) comprises only a small portion of the solar spectrum, it has a disproportionately large photobiological effect on both plants and animals due to its absorption by important biological molecules such as proteins and nucleic acids. This is particularly true in the UV-B (320–280 nm). Ultraviolet radiation has shaped life and its evolution on Earth for as...