Meteorological constraints on marine atmospheric halocarbons and their transport to the free troposphere.

Fuhlbrügge, Steffen (2015) Meteorological constraints on marine atmospheric halocarbons and their transport to the free troposphere. Open Access (PhD/ Doctoral thesis), Christian-Albrechts-Universität Kiel, Kiel, Germany, 169 pp.

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Abstract

This thesis investigates the influence of meteorological conditions and oceanic emissions on atmospheric halocarbons (VSLS) abundances above the oceans and their transport into the free troposphere during three ship campaigns in different oceanic and atmospheric regimes. Meteorological data were measured from ships sensors and by radiosonde launches from the ships during each campaign to investigate atmospheric conditions near the surface, in the marine atmospheric boundary layer (MABL) and in the free troposphere. VSLS were regularly sampled in the surface water and in the marine atmosphere during the cruises. The upwelling regions along the Mauritanian and Peruvian coasts were identified to be medium source regions for atmospheric bromoform, dibromomethane and methyl iodide. Elevated atmospheric mixing ratios of these compounds were found towards the coasts especially above the oceanic upwelling in both regions. Meteorological factors, in particular the MABL characteristics, were identified to impact the atmospheric VSLS mixing ratios and the oceanic emissions significantly. Depending on the height and stability of the MABL as well as the trade inversion, VSLS from oceanic emissions led to an accumulation within the lowermost atmosphere. The resulting low concentration gradients dampened the oceanic emissions and led to minor variations of the marine atmospheric abundances. Within convective activity they could be lifted to the upper troposphere and tropopause. On the opposite, VSLS abundances at the surface and in the MABL were relatively low at coastal regions of the South China and Sulu Seas, despite the high elevated oceanic concentrations and emissions in this area. Here, a convective instable MABL and deep tropical convection led to a rapid exchange of surface air to the free troposphere and a fast distribution of oceanic emissions within the free troposphere. The rapid vertical transport was identified to explain the observed low MABL VSLS mixing ratios.

Document Type: Thesis (PhD/ Doctoral thesis)
Thesis Advisor: Krüger, Kirstin, Marandino, Christa and Quack, Birgit
Keywords: R.V. POSEIDON; R.V. METEOR; R.V. SONNE; SO218; M91; POS399
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
Open Access Journal?: No
Projects: SOPRAN, SHIVA, DRIVE
Expeditions/Models/Experiments:
Date Deposited: 22 Dec 2015 12:59
Last Modified: 25 Oct 2022 12:29
URI: https://oceanrep.geomar.de/id/eprint/30740

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