| Summary: | International audience The SPIRALE (french acronym for infrared absorption spectroscopy by tunable laser diodes) and SWIR-balloon (shortwave infrared Fourier transform spectrometer in nadir-looking) balloon-borne instruments have been launched in the Arctic polar region (Kiruna, Sweden, 67.9°N - 21.1°E) during summer on 7 and 24 August 2009 and on 14 August 2009, respectively. SPIRALE instrument performed in situ measurements of several trace gases including CO and O3 between 10 and 34 km height, with very high vertical resolution (~5 m) and SWIR-balloon instrument measured total column of several species including CO. The balloon CO measurements for the 3 dates are compared with the satellite data from IASI instrument and show a good agreement. However, the stratospheric profile from SPIRALE on 7 August 2009 presents specific structures associated with a tropical intrusion in the low levels (320-380K potential temperature corresponding to 10-14 km altitude) with respect to the 24 august measurements, which is confirmed by the 15-20% increase of the total column of IASI. Their interpretation is made with the help of results from several modelling tools (MIMOSA, FLEXTRA, REPROBUS and GIRAFE) and from satellite data (MODIS on board TERRA/AQUA, IASI instrument on board MetOp-A and GEOS). The results suggest the impact of East Asia urban pollution on the chemistry of polar stratosphere in summer. The SPIRALE O3 vertical profile was also used in correlation with CO to calculate the proportion of recent air in polar stratosphere. SPIRALE and SWIR-balloon flights were part of the balloon campaign conducted by CNES within the frame of the StraPolÉté project funded by French agencies ANR, CNES and IPEV, contributing to the International Polar Year.
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