AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
The Importance of Arctic Seabird Colony Emissions in New Particle Formation and Summertime Arctic Clouds
BETTY CROFT, Greg Wentworth, W. Richard Leaitch, Jennifer Murphy, Jack Kodros, Jonathan Abbatt, Randall V. Martin, Jeffrey R. Pierce, Dalhousie University, Halifax, Canada
Abstract Number: 160 Working Group: Aerosols, Clouds, and Climate
Abstract Measurements at Alert, Nunavut, Canada, with local influences filtered out, show evidence for periodic bursts of new particle formation during the months of May through September. This is indicated by episodes when the measured number of aerosols larger than 10 nm (N10) but less than 20 nm (N20) exceeds 300 cm$^(-3), which happens about 20% of the time during May to September and about 1% of the time during the other months. Our simulations with the GEOS-Chem-TOMAS model using a ternary nucleation scheme show that the amount of free ammonia required to simulate these bursts of new particle formation can only be reached when Arctic seabird colony emissions are implemented in the model. Between May and September, Arctic seabird colonies emit in total about 35 Gg of NH$_3. In this study we use the GEOS-Chem-TOMAS model to examine the budget of the precursors for new particle formation in the Arctic. We compare the GEOS-Chem-TOMAS model with measurements at Alert, Canada and also with recent shipboard measurements taken during the 2014 NETCARE summer campaign. This study provides evidence for the key role of Arctic seabird colony emissions in new particle formation during the high-Arctic summer. The aerosol indirect effect due to the additional nucleation in the Arctic is calculated to be more than -0.25 W m$^(-2) throughout much of the Arctic, and about -1 W m$^(-2) near some bird colonies.