Arctic transport climatologies for the International Arctic System for Observing the Atmosphere (IASOA) and POLARCAT

Several intensive campaigns have recently focused on the transformation and transport of pollutants to the Arctic. During the International Polar Year large-scale coordinated aircraft campaigns will be conducted throughout the circum-Arctic as a part of the POLARCAT project. Additionally, measurements at surface based sites in the IASOA network will be coordinated to capture unique transport events. Toward improved interpretation of the measurements, 10-year transport climatologies are being developed using the Lagrangian particle dispersion model FLEXPART. This paper presents the climatologies for IASOA network, but also introduces FLEXPART products available for the aircraft campaigns. Climatologies are based on 20-day backward model runs for each station using globally gridded 1°x1° input fields from the European Center for Medium Range Weather Forecasting (ECMWF). For analysis of specific measurements, model output for each station is generated at six hour intervals (0, 6, 12, 18 UTC). There are 60 vertical levels, switching to 92 after March, 2006 in the input data. Calculations are based on the release of 40,000 particles representing an idealized inert tracer with an infinite lifetime allowing for interpretation of the results by a wide range of experimentalists. The generated source-receptor relationships are averaged into a seasonal climatology for the various locations. We present 'retroplumes' or three-dimensional Potential Emissions Sensitivity (PES) for the stations. The PES (s kg-1) in each grid cell is proportional to the particle residence time in the cell. For a given source with unit strength (1 kg s-1) the PES provides the simulated mixing ratio at the receptor site. A cluster analysis of particle locations also provides the ability to evaluate the proportion of particles residing in the stratosphere. From this analysis we provide, in addition to the PES, the cluster centroid locations, most analogous to traditional trajectories. Initial results from a concurrent study with HYSPLIT showing seasonal trajectories are also presented