Atmos. Chem. Phys. Discuss., 10, 25389-25433, 2010
www.atmos-chem-phys-discuss.net/10/25389/2010/
doi:10.5194/acpd-10-25389-2010
© Author(s) 2010. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Satellite observations of aerosol transport from East Asia to the Arctic: three case studies
M. Di Pierro, L. Jaeglé, and T. L. Anderson
Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA

Abstract. Vertical profiles of aerosols obtained with the CALIOP lidar onboard CALIPSO are used in conjunction with the GEOS-Chem chemical transport model and NOAA's HYSPLIT trajectory model to document three aerosol export events from East Asia to the Arctic that occurred in the year 2007. During each of these events CALIOP sampled the pollution plumes multiple times over periods of five to seven days. Meridional transport to the Arctic was rapid, taking 3–4 days and was accompanied by net diabatic heating of ~5 °C/day and precipitation in its ascending stage. Once in the Arctic transport was nearly isentropic with slow subsidence and radiative cooling at a rate of 1–1.5 °C/day. We find close agreement between modeled and observed plume in terms of length, altitude, thickness and, within the measurement uncertainties, extinction coefficient. In one event the satellite algorithm misclassifies the aerosol layer as ice clouds as a result of the relatively high depolarization ratio (0.06), likely caused by a somewhat high dust component in the aerosol mixture. The misclassification is more severe at daytime (67% of layers are misclassified) than at nighttime (32%). The two most intense export events occurred in early spring within a three-week time span and are strongly related to a persisting blocking anticyclone that was located in the NW Pacific. Using 500 hPa geopotential height anomalies of these two events along with several others in 2007–2009 we develop a meteorological index that captures 40–60% of the variance of Asian transport events to the Arctic in winter and spring.

Citation: Di Pierro, M., Jaeglé, L., and Anderson, T. L.: Satellite observations of aerosol transport from East Asia to the Arctic: three case studies, Atmos. Chem. Phys. Discuss., 10, 25389-25433, doi:10.5194/acpd-10-25389-2010, 2010.
 
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