Mesoscale transport of atmospheric pollutants across the Alps. (Mesoskaliger Transport von Luftschadstoffen ueber die Alpen)

摘要

Within the framework of the TRACT (=TRANSPORT OF POLLUTANTS OVER COMPLEX TERRAIN. Sub-project of EUROTRAC. An EUREKA environmental project) project, a group of scientists from Italian and Swiss research institutes and the Joint Research Centre of the European Community proposed an experiment called TRANSALP, which was designed to provide rationales for the possibility of transalpine air pollutant transport between the western Po-Valley and the Swiss Plateau and vice-versa. The identification of the respective transport channels in the Alpine region was of particular interest to the project. Independently of political aspects related to the hypothesis that atmospheric pollutants released on one side of the Alps may affect the air quality on the other side, this question deserves specific investigation for the following reason: The knowledge of the flow and turbulence dynamics within the planitary boundary layer over the Alps is very limited and the transport and dispersion conditions for air constituants are certainly totally different than over flat terrain. Little is known e.g. about the meteorological transport processes which effect the transmission of Saharan dust to the Rhine Valley. These considerations led to the decision to carry out a number of field experiments in the Central Alps in order to investigate the transalpine air mass exchange by releasing a passive atmospheric tracer (C(sub 7)F(sub 14)). Between 1989 and 1991 four different tracer experiments were carried out. This report is intended to present and summarize the findings of all the tracer experiments carried out within the framework of TRANSALP. Where already available, a modeling based interpretation is included. (author) figs., tabs., refs.