Abstract
This paper aims at characterising the impact of the atmospheric variability on the aerosol burden and residence time in the Arctic region. For this purpose, a global simulation using an emissions inventory from the year 2000 is performed for the period 2000–2005. The model thus describes a 6-yr evolution of sulphate, black carbon (BC) and mineral dust, whose variability is driven by the atmosphere only. Our simulation is validated, thanks to comparisons with surface observations. The aerosol residence time takes minimum values in fall: 4 d for sulphate and 8 d for BC and dust. It takes maximum values in June: 10 d for sulphate and 16 d for BC and dust. However, from one spring to another, it can vary by about 50% for sulphate, 40% for BC and 100% for dust, depending on the atmospheric variability. In June, sulphate, BC and dust burden averaged over the Arctic region reach respectively maximums of 1.9 mg[S] m−2, 0.2 mg m−2 and 6 mg m−2, characteristic of the so-called Arctic haze. From one year to another, these values can vary by 20% for sulphate, 10% for BC and 60% for dust.
Highlights
The Arctic region was considered not polluted until the year 1950, when pilots flying over the Arctic observed strong pollution, reducing significantly the visibility (Greenaway, 1950)
MOCAGE can simulate the evolution of three types of aerosols compartmented in size-related bins: dust aerosols are divided into five bins between 0.01 mm and 100 mm; and black carbon (BC) and sulphates are both divided into four bins between 0.001 mm and 10 mm
As scavenging by ice droplets is taken into account in our model, aerosol burden and residence time are expected to be well simulated in the Arctic region, where snow represents a large part of the precipitation (Fig. 1)
Summary
The Arctic region was considered not polluted until the year 1950, when pilots flying over the Arctic observed strong pollution, reducing significantly the visibility (Greenaway, 1950). Sharma et al (2006) pointed out that pollutants surface concentrations at some Arctic stations can be quite different from one year to another due to atmospheric inter-annual variability: pollutants surface concentrations in Northern America are 40% higher over the years 1991Á 1994 than over the years 1995Á1998, a difference they explained by a more frequent positive phase of the North Atlantic Oscillation in the first period than in the second, which brings more pollutants from Eurasia into the Arctic via a stronger Siberian anticyclone. Our study is based on a multiyear aerosol simulation using constant emissions to evaluate the impact of the atmospheric inter-annual variability on the aerosol burden in the whole Arctic atmosphere. This analysis helps explaining the intra- and inter-annual variability of both the residence time and the aerosol burden in the Arctic region.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
