Aerosol Characterization in the Arctic Region during Cold Air Outbreaks

LINTONG CAI, Sunandan Mahant, Emma Weissburg, Anna Robertson, Jefferson Snider, Markus Petters, University of California, Riverside

     Abstract Number: 491
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
Cold air outbreaks (CAOs) over the Norwegian and Greenland Seas are characterized by pronounced air-sea energy exchanges. During CAOs, the fluxes are a consequence of the sea surface temperature being larger than the air temperature. The temperature gradient fosters the formation of convective marine boundary layer clouds, often accompanied by precipitation and occasionally the formation of polar lows. The Cold-Air Outbreak Experiment in the Sub-Arctic Region (CAESAR) involved the NSF/NCAR C-130 aircraft in research flights across the open waters spanning northern Sweden to the Arctic ice edge, and offered a comprehensive perspective on CAOs by deploying a suite of airborne remote sensors, aerosol, cloud, precipitation, and trace gas probes. Here we describe the fields of the particle size distributions, estimated PM2.5 mass concentration, and black carbon size distributions and mixing state from the aerosol probes deployed during CAESAR. Our findings show surprisingly large spatial and temporal variability in the flight domain, including surprisingly large concentrations of black carbon aerosol over the sea ice. The data is used to evaluate aerosol composition fields simulated by the Goddard Earth Observing System composition forecast . Data-model comparison shows reasonable agreement between simulated and observed aerosol fields. These measurements yield valuable insights into aerosol-cloud interactions over the Norwegian and Greenland Seas and serve to enhance the validation of weather forecasts and climate models.