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Commission Européenne (CORDIS) 2000

MINATROC Mineral dust and tropospheric chemistry

Mineral dust - Tropospheric chemistry

CORDIS (Service Communautaire d’Information sur la Recherche et le Développement) Commission Européenne

Titre : MINATROC Mineral dust and tropospheric chemistry

Région : Global

Code du projet : EVK2-CT-1999-00003

Durée : From 2000-03-01 to 2003-02-28

Descriptif
This project focuses on the transformation of atmospheric pollutants from Europe in the presence of mineral dust over S. Europe and Africa. Mineral dust is the single most abundant aerosol. It is injected into the atmosphere by the action of surface winds on dry soils from cultivated regions as well as arid regions, especially over Southern Europe, North Africa and in Asia. Estimations of the global source strength vary from » 200 to 5000 Mt /yr, representing about 50 % of the total production of tropospheric aerosols by natural and anthropogenic sources together. At the global scale, the most important regions of dust emission are located near industrial regions with fast growing anthropogenic emissions of precursors of ozone and aerosols. Examples are the Sahel/Sahara (close to the Mediterranean Area) and the S. E. Asia deserts (close to Japan and to Eastern China). Reactions on the surface of aerosol particles (i.e. heterogeneous reactions) taking place in the troposphere can affect the radiative budget and alter the atmospheric content of key atmospheric species. Predicting the impact of changing anthropogenic emissions on atmospheric composition and climate, in Southern Europe and the Mediterranean Basin, requires an understanding of dust/pollution interactions. A few model studies have investigated atmospheric chemistry when dust and anthropogenic emissions interact showing a substantial effect on nitrate, sulphate and ozone. There is however a chronically shortage of laboratory data to back-up the (heterogeneous) reaction schemes used in present modelling studies. Furthermore, there is a lack of specific field data to show unambiguously the effect of dust/gas interactions We propose a multi-disciplinary approach that involves a high degree of synergy between laboratory studies, two field experiments and a modelling strategy. This project will eventually perform a study of how the gas/dust interactions studied affect the IPCC (2000) estimates of radiative forcing by ozone and anthropogenic aerosols.
The project main objectives are : first, to quantify the impact of mineral dust on tropospheric photochemical cycles leading to ozone production and destruction, second to quantify the specific direct radiative effect of secondary aerosol (e.g. sulphate and organics) in the present of mineral dust. This results in an enhancement in our understanding and predictive capabilities regarding atmospheric composition change and climate. The multi-disciplinary approach of the project enables us to determine the efficiency and mechanism of the interaction of mineral dust with a number of important trace gases using laboratory experiments. Two field experiments of 4 weeks each allow characterizing both the gas phase and the aerosol state before and after an air parcel encounters Saharan dust. A simulation by a chemical transport model including detailed dust / gas interactions using the meteotological fields of the campaigns of observation will help to analyse and quantify the influence of mineral dust on photochemical oxidant cycles and ozone concentrations. One aspect is the divergence in modelled and measured NOy / NOz concentrations. Furthermore, we quantify the degree to which radiative cooling by secondary aerosols (sulphate, organics) aerosols is modified if the aerosol is internally/externally mixed with mineral dust. Particular attention is put on the influence of reactions on mineral dust on ozone concentrations and how it affects radiation balance. We further assess this impact for future conditions using the IPCC scenario.

Participants au projet
Coordinateur : CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE (France)
Participants :
COMMISSARIAT A L’ENERGIE ATOMIQUE France
COMMISSION OF THE EUROPEAN COMMUNITIES Italy
MAX-PLANCK-GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V. Germany
NATIONAL RESEARCH COUNCIL OF ITALY Italy
SWISS FEDERAL INSTITUTE OF TECHNOLOGY LAUSANNE Switzerland
University of Cambridge United Kingdom

Budget
Coût total : EUR 1 734 300
Contribution UE : EUR 1 074 400

Présentation : Commission Européenne

Page publiée le 13 octobre 2016, mise à jour le 29 octobre 2017