Bio-Organic Physical Chemistry of the Arctic and Subarctic

Aerosols and their interactions with clouds "contribute the largest uncertainty to the total radiative forcing" driving climate change. The aerosol-cloud-induced uncertainty is as large as the effect of increasing atmospheric concentrations of well-mixed greenhouse gases. The warmest nucleation temperatures have been attributed to bacterial ice nuclei, which might play regional roles, while dust particles potentially play a global role as ice nuclei. We have been involved in several field campaigns during the last 10 years in Arctic sites in Alaska (USA), Resolute and Alert (Canada), and several Canadian sub-Arctic sites, as part of international campaigns and from permanent sites. We present our results on novel processes involving snow-air interactions and their impacts on tropospheric aerosols transformation and cloud nucleation.