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On the relationship between Arctic ice clouds and polluted air masses over the North Slope of Alaska in April 2008
Abstract : Recently, two Types of Ice Clouds (TICs) properties have been characterized using ISDAC airborne measurements (Alaska, April 2008). TIC-2B were characterized by fewer (<10 L−1) and larger (>110 μm) ice crystals, a larger ice supersaturation (>15%) and a fewer ice nuclei (IN) concentration (<2 order of magnitude) when compared to TIC-1/2A. It has been hypothesized that emissions of SO2 may reduce the ice nucleating properties of IN through acidification, resulting to a smaller concentration of larger ice crystals and leading to precipitation (e.g. cloud regime TIC-2B) because of the reduced competition for the same available moisture. Here, the origin of air masses forming the ISDAC TIC-1/2A (1 April 2008) and TIC-2B (15 April 2008) is investigated using trajectory tools and satellite data. Results show that the synoptic conditions favor air masses transport from the three potentials SO2 emission areas to Alaska: eastern China and Siberia where anthropogenic and biomass burning emission respectively are produced and the volcanic region from the Kamchatka/Aleutians. Weather conditions allow the accumulation of pollutants from eastern China/Siberia over Alaska, most probably with the contribution of acid volcanic aerosol during the TIC-2B period. OMI observations reveal that SO2 concentrations in air masses forming the TIC-2B were larger than in air masses forming the TIC-1/2A. Airborne measurements show high acidity near the TIC-2B flight where humidity was low. These results strongly support the hypothesis that acidic coating on IN are at the origin of the formation of TIC-2B.
Cited literature [60 references]
https://hal.archives-ouvertes.fr/hal-00789168
Contributor : Catherine Cardon Connect in order to contact the contributor
Submitted on : Friday, December 18, 2015 - 10:11:25 AM
Last modification on : Tuesday, November 16, 2021 - 4:47:03 AM
Long-term archiving on: : Saturday, April 29, 2017 - 8:58:11 PM
Contributor : Catherine Cardon Connect in order to contact the contributor
Submitted on : Friday, December 18, 2015 - 10:11:25 AM
Last modification on : Tuesday, November 16, 2021 - 4:47:03 AM
Long-term archiving on: : Saturday, April 29, 2017 - 8:58:11 PM
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acp-14-1205-2014.pdf
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