New collaborators for IAGOS
18 March 2013
The IAGOS team in Toulouse is very
happy to welcome 2 new collaborators :
- Audrey GAUDEL is the new collaborator for the MACC-II program, on the VAL sub-project.
On the supervision of Valérie Thouret and Hannah Clark, she is responsible of the automatic validation of the models with IAGOS data.
Visit the dedicated web site: http://www.iagos.fr/macc
- Benoît GAUTRON is the new
collaborator for the IGAS project. On the supervison of Valérie Thouret and Damien
Boulanger, he is responsible of the further development of the IAGOS
central database including metadata and interoperability.
Visit the web site project: http://www.igas-project.org
18 March 2013
P. G. Hess and R.
Zbinden, Stratospheric impact on tropospheric ozone variability
and trends: 1990–2009, Atmos. Chem. Phys., 13, 649–674,
inﬂuence of stratospheric ozone on the interannual variability and
trends in tropospheric ozone is evaluated between 30 and 90◦ N from
1990–2009 using ozone measurements and a global chemical transport
model, the Community Atmospheric Model with chemistry (CAM-chem).
Long-term measurements from ozonesondes, at 150 and 500 hPa, and the
Measurements of OZone and water vapour by in-service Airbus aircraft
programme (MOZAIC), at 500 hPa, are analyzed over Japan, Canada, the
Eastern US and Northern and Central Europe. The measurements
generally emphasize northern latitudes, although the simulation
suggests that measurements over the Canadian, Northern and Central
European regions are representative of the large-scale interannual
ozone variability from 30 to 90◦ N at 500 hPa. CAM-chem is run with
input meteorology from the National Center for Environmental
Prediction; a tagging methodology is used to identify the
stratospheric contribution to tropospheric ozone concentrations. A
variant of the synthetic ozone tracer (synoz) is used to represent
stratospheric ozone. Both the model and measurements indicate that on
large spatial scales stratospheric interannual ozone variability
drives signiﬁcant tropospheric variability at 500 hPa and the
surface (Fig 5 below). In particular, the simulation and the
measurements suggest large stratospheric inﬂuence at the surface
sites of Mace Head (Ireland) and Jungfraujoch (Switzerland) as well
as many 500 hPa measurement locations. Both the measurements and
simulation suggest the stratosphere has contributed to tropospheric
ozone trends. In many locations between 30–90◦ N 500 hPa ozone
significantly increased from 1990–2000, but has leveled off since
(from 2000–2009). The simulated global ozone budget suggests global
stratosphere-troposphere exchange increased in 1998–1999 in
association with a global ozone anomaly. Discrepancies between the
simulated and measured ozone budget include a large underestimation
of measured ozone variability and discrepancies in long-term
stratospheric ozone trends. This suggests the need for more
sophisticated simulations including better representations of
stratospheric chemistry and circulation.
Figure a, the differences in the tropospheric burden of ozone (O3,
solid black), of stratospheric ozone (O3s, dotted black),
tropospheric chemical ozone (O3NOX, blue) and synoz* (representative
of STE, green) are given from their 1990 annually averaged burden
(354 Tg, 190 Tg, 164 Tg and 253 Tg, respectively).
In Figure b, the change in net STE (blue lines), net chemistry (red) and surface deposition (green) compared to 1990 is given for both O3 (solid lines) and O3S (dotted lines).
Start of the new IGAS project
21 January 2013