Melissa Gervais

(Columbia University, Lamont-Doherty Earth Observatory)

Arctic Air Masses in a Warming World

What Meteo Colloquium GR UG
When Nov 02, 2016
from 03:30 pm to 04:30 pm
Where 112 Walker Building
Contact Name David Titley
Contact email
Contact Phone (814) 867-4750
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Melissa GervaisWith global climate change, we can expect there to be significant changes in the development of air masses in Arctic regions. In particular, Arctic amplification results in greater warming over the Arctic compared to the lower latitudes on average. In this study, January-February equivalent potential temperatures at 850hPa, from the Community Earth System Model Large-Ensemble (CESM-LE) RCP 8.5 scenario, are used to examine changes in Arctic air masses throughout the 21st century. In addition to the average change, we are interested in how patterns of equivalent potential temperature anomalies and their frequencies will change in the future. A technique of self-organizing maps is employed to define archetypes of the air mass anomaly fields with the climatological change removed. Our results show that patterns with cold equivalent potential temperature anomalies situated over the central Arctic, associated with a positive AO pattern, are becoming less frequent with time. There is an increase in the frequency of patterns with warm or cold anomalies over North America associated with amplified 500hPa flow over North America. There is also a decline in patterns that have anomalously high equivalent potential temperature over the North Atlantic. This pattern is associated with intense ridging in the 500hPa flow over the North Atlantic and colder equivalent potential temperature over Europe. The results presented demonstrate how the distribution of weather regimes in the Arctic and midlatitudes will change in the future, an important aspect of understanding the impact of climate change on society.