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Cologne Geosciences Colloquium: How the Arctic warms within days and over decades
16 April
17:00 Uhr - 18:00 Uhr
Zülpicher Straße 49a
50674 Köln

Link: http://lageplan.uni-koeln.de/#!310a

Cologne Geosciences Colloquium:

How the Arctic warms within days and over decades

Dr Felix Pithan, AWI - Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven

Global warming is known to be amplified in the Arctic because of strong positive feedbacks that are specific to high latitudes: As snow and ice melt, more sunlight is absorbed at the surface in summer (surface albedo feedback), and surface warming, especially in winter, is concentrated in the lowest levels, which makes it harder for additional energy to escape to space (lapse-rate feedback).

In recent years, wintertime warm events with temperatures near the freezing point around the North Pole have attracted public and scientific attention. These events are caused by intrusions of warm, moist mid-latitude air into the central Arctic that lead to development of cloud liquid, which in turn shields the surface from cooling to space through the otherwise very transparent Arctic atmosphere.

In this talk, I will give an overview of recent research into the transformation of air masses that enter or leave the Arctic, discuss how these events are connected to the feedbacks driving Arctic amplification of climate change and how the events themselves will change in a warming climate. Processes ranging from boundary-layer turbulence and cloud microphysics over radiation and the development of high-pressure systems to rossby-wave breaking and sudden stratospheric warmings interact to generate and control these air mass transformations. Activities within and beyond the ongoing year of polar prediction will provide us with fascinating, unprecedented insights into these processes in the next few years.