Research Reports on Ozone from D. Zyryanov and Colleagues Provide New Insights
2012 MAY 21 - (VerticalNews.com) -- "A detailed 3-D evaluation of an ensemble of five regional Chemistry Transport Models (RCTM) and one global CTM with focus on free tropospheric ozone over Europe is presented. It is performed over a summer period (June to August 2008) in the context of the GEMS-RAQ project," scientists in Bologna, Italy report.
"A data set of about 400 vertical ozone profiles from balloon soundings and commercial aircraft at 11 different locations is used for model evaluation, in addition to satellite measurements with the infrared nadir sounder (IASI) showing largest sensitivity to free tropospheric ozone. In the middle troposphere, the four regional models using the same top and boundary conditions from IFS-MOZART exhibit a systematic negative bias with respect to observed profiles of about -20%. Root Mean Square Error (RMSE) values are constantly growing with altitude, from 22% to 32% to 53%, respectively for 0-2 km, 2-8 km and 8-10 km height ranges. Lowest correlation is found in the middle troposphere, with minimum coefficients ® between 0.2 to 0.45 near 8 km, as compared to 0.7 near the surface and similar values around 10 km. A sensitivity test made with the CHIMERE mode also shows that using hourly instead of monthly chemical boundary conditions generally improves the model skill (i.e. improve RMSE and correlation). Lower tropospheric 0-6 km partial ozone columns derived from IASI show a clear North-South gradient over Europe, which is qualitatively reproduced by the models. Also the temporal variability showing decreasing ozone concentrations in the lower troposphere (0-6 km columns) during summer is well reproduced by models even if systematic bias remains (the value of the bias being also controlled by the type of used boundary conditions)," wrote D. Zyryanov and colleagues.
The researchers concluded: "A multi-day case study of a trough with low tropopause was conducted and showed that both IASI and models were able to resolve strong horizontal gradients of middle and upper tropospheric ozone occurring in the vicinity of an upper tropospheric frontal zone."
Zyryanov and colleagues published their study in Atmospheric Chemistry and Physics (3-D evaluation of tropospheric ozone simulations by an ensemble of regional Chemistry Transport Model. Atmospheric Chemistry and Physics, 2012;12(7):3219-3240).
For additional information, contact D. Zyryanov, Italian Natl Agcy New Technol Energy & Sustainabl, Bologna, Italy.
The publisher's contact information for the journal Atmospheric Chemistry and Physics is: Copernicus Gesellschaft Mbh, Bahnhofsallee 1E, Gottingen, 37081, Germany.
Keywords: City:Bologna, Country:Italy, Region:Europe, Climate Change, Global Warming
This article was prepared by VerticalNews Global Warming editors from staff and other reports. Copyright 2012, VerticalNews Global Warming via VerticalNews.com.