The influence of deep convection on HCHO and H<sub>2</sub>O<sub>2</sub> in the upper troposphere over Europe
- Publikationstyp:
- Zeitschriftenaufsatz
- Metadaten:
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- Abstract
- <jats:p>Abstract. Deep convection is an efficient mechanism for vertical trace gas transport from the Earth's surface to the upper troposphere (UT). The convective redistribution of short-lived trace gases emitted at the surface typically results in a C-shaped profile. This redistribution mechanism can impact photochemical processes, e.g. ozone and radical production in the UT on a large scale due to the generally longer lifetimes of species like formaldehyde (HCHO) and hydrogen peroxide (H2O2), which are important HOx precursors (HOx = OH + HO2 radicals). Due to the solubility of HCHO and H2O2 their transport may be suppressed as they are efficiently removed by wet deposition. Here we present a case study of deep convection over Germany in the summer of 2007 within the framework of the HOOVER II project. Airborne in-situ measurements within the in- and outflow regions of an isolated thunderstorm provide a unique data set to study the influence of deep convection on the transport efficiency of soluble and insoluble trace gases. Comparing the in- and outflow indicates almost undiluted transport of insoluble trace gases from the boundary layer to the UT. The ratios of out/inflow of CO and CH4 are 0.94 ± 0.04 and 0.99 ± 0.01, respectively. For the soluble species HCHO and H2O2 these ratios are 0.55 ± 0.09 and 0.61 ± 0.08, respectively, indicating partial scavenging and washout. Chemical box model simulations show that post-convection secondary formation of HCHO and H2O2 cannot explain their enhancement in the UT. A plausible explanation, in particular for the enhancement of the highly soluble H2O2, is degassing from cloud droplets during freezing, which reduces the retention coefficient. </jats:p>
- Autoren
- Heiko Bozem
- Andrea Pozzer
- Hartwig Harder
- Monica Martinez
- Jonathan Williams
- Jos Lelieveld
- Horst Fischer
- DOI
- 10.5194/acp-2017-154
- Datum der Veröffentlichung
- 2017
- Status
- Published
- Herausgeber URL
- http://dx.doi.org/10.5194/acp-2017-154
- Datum der Datenerfassung
- 2020
- Titel
- The influence of deep convection on HCHO and H&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; in the upper troposphere over Europe
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