Changes in aerosol properties during spring-summer period in the Arctic troposphere

[摘要] The change in aerosol properties during the transition from the morepolluted spring to the clean summer in the Arctic troposphere was studied. Asix-year data set of observations from Ny-Ålesund on Svalbard, coveringthe months April through June, serve as the basis for the characterisationof this time period. In addition four-day-back trajectories were used todescribe air mass histories. The observed transition in aerosol propertiesfrom an accumulation-mode dominated distribution to an Aitken-mode dominateddistribution is discussed with respect to long-range transport andinfluences from natural and anthropogenic sources of aerosols and pertinenttrace gases. Our study shows that the air-mass transport is an importantfactor modulating the physical and chemical properties observed. However,the air-mass transport cannot alone explain the annually repeated systematicand rather rapid change in aerosol properties, occurring within a limitedtime window of approximately 10 days. With a simplified phenomenologicalmodel, which delivers the nucleation potential for new-particle formation,we suggest that the rapid shift in aerosol microphysical properties betweenthe Arctic spring and summer is mainly driven by the incoming solarradiation in concert with transport of precursor gases and changes incondensational sink.

[学科分类] 大气科学