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| Titel |
Reactive Halogen Species in the Marine Boundary Layer: A Comparision of the Mauretanian and the Peruvian upwelling regions |
| VerfasserIn |
Johannes Lampel, Jens Tschritter, Denis Pöhler, Katja Grossmann, Martin Horbanski, Udo Frieß, Ulrich Platt |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082497
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| Zusammenfassung |
| Reactive halogen species (RHS) such as bromine oxide (BrO) or iodine oxide (IO) play a
major role in the chemistry of ozone in both, the troposphere, and the stratosphere and
possibly influence the ozone budget on a global scale. In order to estimate the amount of RHS
release from marine sources DOAS measurements in three different upwelling regions
(Mauritanian, African equatorial and Peruvian) as well as long-term-observations at the Cape
Verde Atmospheric Observatory (CVAO) were performed within the SOPRAN Project
(BMBF Förderkennzeichen 03F0611F).
In 2010 the HaloCaVe campaign with a set of DOAS instruments on the CVAO and RV
Poseidon allowed for an intercomparision of Long-Path-DOAS (LP), Multi-Axis-DOAS
(MAX) and Cavity-Enhanced-DOAS (CE) measurements on shore as well as for extending
these observations to a larger area with the simultaneous ship-borne MAX-DOAS
measurements during the DRIVE campaign from Gran Canaria to Cape Verde and back along
the mauretanian coast. A re-evaluation of the entire data set is presented. LP- and
MAX-DOAS observations show significant BrO concentrations of several ppt with strong
variations from day to day and a diurnal cycle with a maximum at sunrise and sunset and a
minimum during noon. In opposite to previous measurements, IO was below the
detection limit of 0.5 ppt for the LP-DOAS and CE-DOAS instrument. From the ship
(DRIVE campaign) locally restricted BrO hotspots with mixing ratios of up to
10ppt were observed in the Mauritanian costal upwelling. These findings allow new
conclusions on the relevance of halogens on this marine environment which will be
presented.
Within the SOPRAN cruise M91 on RV Meteor the upwelling region along the coast of
Peru has been investigated in December 2012. First results from MAX-DOAS and
CE-DOAS measurements will be presented and compared to those from the Atlantic.
Both instruments measured NO2, IO and glyoxal mixing ratios, the MAX-DOAS
additionally BrO and formaldehyde. We observed significant differences for IO and BrO.
Observed glyoxal slant column densities were significantly smaller than previously
reported for this area. These recent findings raise several questions about the halogen
mechanisms.
Comparing both regions might give hints to the relevant release mechanisms and
thus furthermore improve estimations of the global influence of reactive halogen
species on tropospheric chemistry and the local relevance. First conclusions will be
presented. |
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