Evidence for Changes in Arctic Cloud Phase Due to Long-Range Pollution Transport
Abstract
Reduced precipitation rates allow pollution within air parcels from midlatitudes to reach the Arctic without being scavenged. We use satellite and tracer transport model data sets to evaluate the degree of supercooling required for 50% of a chosen ensemble of low-level clouds to be in the ice phase for a given meteorological regime. Our results suggest that smaller cloud droplet effective radii are related to higher required amounts of supercooling but that, overall, pollution plumes from fossil fuel combustion lower the degree of supercooling that is required for freezing by approximately 4 °C. The relationship between anthropogenic plumes and the freezing transition temperature from liquid to ice remains to be explained.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- October 2018
- DOI:
- 10.1029/2018GL079873
- Bibcode:
- 2018GeoRL..4510709C
- Keywords:
-
- clouds;
- aerosol-cloud interaction;
- ice nucleation;
- Arctic;
- space-based measurements