Oceans cover 70% of the Earth surface, and are the primary source for halogens in the atmosphere. Further, the amount of dissolved organic carbon (DOC) in the world’s oceans is comparable to that of atmospheric CO2. Yet oceans are currently believed primarily to be a receptor for organic carbon emitted over land. Recent our observations of very short-lived and water soluble molecules in the marine boundary layer above the remote Pacific Ocean (Sinreich et al., 2010), and iodine oxide in the free troposphere (Dix et al., 2013) remain as of yet unexplained by atmospheric models. Organic carbon and halogens are relevant in the atmosphere because they influence the reactive chemical removal pathways of climate active gases (i.e., ozone, methane, dimethyl-sulfide), and can modify aerosols. Atmospheric models tend to predict more BrO, and less IO than is observed in the remote marine boundary layer (MBL); satellite retrievals of IO and glyoxal, the smallest alpha-dicarbonyl compound, further remain untested in lack of vertically resolved observations of these species in the tropical free troposphere. The Tropical Ocean tRoposphere Exchange experiment TORERO (Jan/Feb 2012) deployed an innovative payload of optical spectroscopic-, mass spectrometric-, and remote sensing instruments aboard the NSF/NCAR GV aircraft (HIAPER), and aboard a NOAA ship to measure very short lived halogen species, oxygenated hydrocarbons, and volatile organic compounds (some 50+ species), aerosol size distributions, optical properties, and photolysis frequencies over the full tropospheric air column (0-15km altitude) above the eastern tropical Pacific Ocean. This talk describes selected TORERO measurements, and exploits unique properties of tracer molecules (i.e., volatility, solubility), as well as their spatial distributions to provide a process level understanding of the sources and sinks of organic carbon and halogens in the tropical atmosphere. The oxidative capacity (OH-, Br-, I- radical abundance) is assessed with a particular focus on the tropical free troposphere, where most of tropospheric ozone mass resides, 60-80% of the global methane destruction occurs, and mercury oxidation rates are accelerated at low temperatures.

Diese Veranstaltung ist Teil der Reihe Karlsruher Meteorologisches Kolloquium

Referent/in
Prof. Dr. Rainer Volkamer

University of Colorado at Boulder & the TORERO team
CIRES & Department of Chemistry and Biochemistry

Veranstalter
Prof. Dr. J. Orphal
IMK-ASF
Karlsruher Institut für Technologie (KIT)
Karlsruhe
Tel: +49 721 608 29121
Fax: +49 721 608 24742
E-Mail: johannes orphal ∂does-not-exist.kit edu

Zielgruppe
Wissenschaftliche Mitarbeitende