 |
| Titel |
Modelling study of the impact of deep convection on the UTLS air composition – Part 2: Ozone budget in the TTL |
| VerfasserIn |
E. D. Rivière, V. Marecal, N. Larsen, S. Cautenet |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 6 ; Nr. 6, no. 6 (2006-05-18), S.1585-1598 |
| Datensatznummer |
250003824
|
| Publikation (Nr.) |
 copernicus.org/acp-6-1585-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| In this second part of a series of two papers which aim to study the local
impact of deep convection on the chemical composition of the Upper
Troposphere and Lower Stratosphere (UTLS), we focus on ozone simulation
results using a mesoscale model that includes on-line chemistry. A severe
convective system observed on 8 February 2001 at Bauru, Brazil, is studied.
This unorganised convective system is composed of several convective cells
that interact with each other. We show that there is an increase in the ozone
concentration in the tropical transitional layer (TTL) in the model during
this event, which is compatible with ozone sonde observations from Bauru
during the 2004 convective season. The model horizontal variability of ozone
in this layer is comparable with the variability of the ozone sonde
observations in the same area. The calculation of the ozone budget in the TTL
during a 24 h period in the area of the convective system shows that the
ozone behaviour in this layer is mainly driven by dynamics. The horizontal
flux at a specific time is the main contribution in the budget, since it
drives the sign and the magnitude of the total ozone flux. However, when
averaged over the 24 h period, the horizontal flux is smaller than the
vertical fluxes, and leads to a net decrease of ozone molecule number of
23%. The upward motions at the bottom of the TTL, related to the
convection activity is the main contributor to the budget over the 24h
period since it can explain 70% of the total ozone increase in the TTL,
while the chemical ozone production inside the TTL is estimated to be 29%
of the ozone increase, if NOx production by lightning (LNOx) is
taken into account. It is shown that downward motion at the tropopause
induced by gravity waves generated by deep convection is non negligible in
the TTL ozone budget, since it represents 24% of the ozone increase. The
flux analysis shows the importance of the vertical contributions during the
life time of the convective event (about 8 h). The TTL ozone is driven
out of the domain horizontally by the convective outflow during this period,
limiting the ozone increase in this layer. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|