HR: 17:45h
AN: A14D-08    [Abstracts]
TI: Assessment of Impact of Ship Emissions Over the Summertime Mediterranean
AU: * Marmer, E
EM: elina.marmer@jrc.it
AF: European Commission JRC IES Climate Change Unit, TP 290, Ispra, VA 21020, Italy
AU: Vignatti, E
AF: European Commission JRC IES Climate Change Unit, TP 290, Ispra, VA 21020, Italy
AU: Langmann, B
AF: NUIG Department of Experimental Physics, University Road, Galway, none, Ireland
AU: Dentener, F
AF: European Commission JRC IES Climate Change Unit, TP 290, Ispra, VA 21020, Italy
AU: Hjorth, J
AF: European Commission JRC IES Climate Change Unit, TP 290, Ispra, VA 21020, Italy
AU: Velchev, K
AF: European Commission JRC IES Climate Change Unit, TP 290, Ispra, VA 21020, Italy
AU: Cavalli, F
AF: European Commission JRC IES Climate Change Unit, TP 290, Ispra, VA 21020, Italy
AU: van Aardenne, J A
AF: European Commission JRC IES Climate Change Unit, TP 290, Ispra, VA 21020, Italy
AB: The summertime Mediterranean atmosphere is one of the world's most polluted regions in terms of photochemical ozone formation and aerosol loading. Meteorological conditions during the summer favor the accumulation of primary emitted pollutants, high solar radiation intensity enhances the formation of secondary gases and aerosols. Removal of pollutants by precipitation is inhibited by summertime aridity.
The seagoing ships as sources of air pollution and global climate change give cause for growing concern. This study investigates their contribution to the atmospheric pollution over the Mediterranean. Ship emission inventories widely differ due to different methodologies applied (top-down and bottom-up). In 2005, the JRC has launched a measurement campaign on board of a Mediterranean cruise ship, sampling ozone and black carbon, as well as aerosol size distribution. This unique data set is a valuable contribution to establishing the Mediterranean atmosphere pollution levels.
We have utilized two different models and three different emission inventories to tackle this problem and to assess which of the inventories produces better results as compared to observations. The global chemistry transport model TM5 (Krol et al., 2005) with the zoomed finer resolution over Europe and the North Atlantic, samples ozone and aerosols "synchronous" with the cruise ship. Two different global ship emission inventories have been implemented, and the model results have been evaluated with the ship samples. Modelled and observed ozone values frequently exceed 60 ppb during spring and early summer. The contribution of ship emissions to the ozone levels is below 10% if the EDGAR* (with modifications for OC and BC) ship emissions are applied, it reaches well over 15% during summer in Western and Central Mediterranean with the Eyring et al. (2005) ship emission inventory, being in better agreement with the ship measurements. The opposite is true for the black carbon, its contribution from ships is below 10% applying the Eyring et al. (2005) ship emissions, but over 40% close to the main ship routes with the EDGAR* inventory, which performs better for black carbon. The advantage of the global model is its ability to simulate the cross continental transport of air pollution into the Mediterranean and thus to distinguish its contribution from the local pollution.
To take advantage of a finer resolved regional Vestreng (2003) ship emission inventory we have utilized the regional atmosphere chemistry model REMOTE (Langmann, 2000). Partitioning SOx emissions into land and water sources was applied to investigate their respective impact on the sulfate aerosol concentration, the total aerosol burden and the direct radiative forcing (Marmer and Langmann, 2005). 54% of the total sulfate aerosol column burden over the Mediterranean in summer was attributed to ship emissions. The model performance was better over the Eastern Mediterranean, where land emissions dominated the atmospheric composition, while over the Western Mediterranean the simulated concentrations were underestimated, allowing the conclusion that the implemented ship emissions of SOx were underestimated.
Combining both models, the three inventories and the ship and coastal measurements we quantify the impact of ship emissions and outline the strengths and weaknesses of each of the available inventories.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting