Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

O3 loss studies

In this project ozone profiles retrieved from GOME measurements were validated with more then 750 ozone sonde measurements at different geo-locations. The validation showed that daily and seasonal variability of the sonde profiles were accurately reproduced by the GOME measurements. The measurements are in agreement within uncertainty limits (better than 5 %) of the O3 profile measurements and the different footprints for the sonde and GOME measurements (with the exception of the tropics where exist small biases in the GOME O3 profiles: tropospheric O3 is slightly underestimated and stratospheric O3 is overestimated, both by about 5-10 %).

A comparison of TM5 model results with the GOME measurements was made for the period 1996-1998. The TM5 model is a chemistry-transport model, i.e. wind fields - which are obtained from a weather forecast model - are used to calculate transport of chemical species. The comparison showed that the model reproduces the observed stratospheric O3 variability, both on short and long timescales.

Three biases were identified: the lack of arctic stratospheric O3 depletion in the model results in too much high latitude O3 while the model also overestimates tropospheric O3 due to an incorrect representation of tropospheric chemistry by the model. The third and most prominent bias was the overestimation of mid-latitude lower and middle stratospheric O3 and subsequent underestimation of tropical stratospheric O3. This bias is caused by the too fast stratospheric transport from the tropics to the poles, showing the potential of using stratospheric O3 measurements to study this topic (which is a known feature of chemistry-transport models).

More information on the QUILT project can be found at:

Reported by

National Institute for Space Research - SRON
Sorbonnelaan 2
3584 CA Utrecht
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