A deposition experiment of SO_2, O_3 and NH_3 in a suburban area

摘要

Deposition processes are a very important part of the atmospheric dispersion models. They can be defined as the removal from the atmosphere of the different chemical compounds which are deposited over the different surfaces which are found in a complex environment such us urban centers and surroundings. Mesoscale Transport Models use the deposition modules to remove pollutants from the atmosphere and the quality and importance of the deposition parameterization processes is out of question. The classical approach of deposition processes into the dispersion models has been based on the so-called "big-leaf" approach which is based on a former version of the resistance technique introduced in the 1970's. This is based on the accurate parameterization of the resistances, particularly on the canopy resistance. The characterization of the different land-use types and the quantification of the different parameters for the different chemical compounds is based on field experiments carried out with extreme high sophisticated instrumentation usually based on the eddy-correlation technique. In this contribution, we present first preliminary results on a field deposition experiment based on the eddy-correlation and modified Bowen-ratio technique for ozone (eddy-correlation) and SO_2 and ammonia (Bowen-ratio). The location of the field experiment is a Military Airport (Cuatro Vientos) located 10 km to the West of the Madrid City center. First results show a good agreement obtained with those carried out in Northern parts of Europe however several up draft fluxes and high deposition velocity values are found because of the dry environmental and surface conditions which are typical for the Southern parts of Europe.