Title: Impacts of Arctic Sea Ice on Atlantic and Pacific Climate
Lecturer: Prof. Aiguo Dai (University at Albany, State University of New York)
Inviter: Prof. Yaocun Zhang, Prof. Danqing Huang
Time: Thursday June 20, 2024 at 2:30 PM
Venue: Lecture Hall D103, School of Atmospheric Sciences
Abstract: To fully understand the potential impacts of the shrinking Arctic sea ice, we need to better understand the various roles of Arctic sea ice plays in our climate. In this talk, I use CESM1 simulations with and without the sea ice-air interactions and observations to show that variations in cold-season sea ice concentrations (SIC) around Arctic marginal ice zones significantly amplify multidecadal variations in surface latent and sensible fluxes from the Labrador Sea to the Nordic Seas, leading to larger variations in upper ocean density and deep water formation therein, then amplifying the amplitudes of Atlantic Multidecadal Oscillation (AMO) and the Atlantic meridional overturning circulation. In the Pacific sector, SIC variations from the Bering Sea to Okhotsk Sea (BOS) lead to increased absorption of solar radiation due to asymmetric albedo effects of SIC anomalies. This results in warming in the northern North Pacific Ocean, which excites an anomalous tropospheric Rossby wave propagating equatorward into the tropics to strengthen cross-equator winds and deepen the thermocline there. Thus, Arctic sea ice–air interactions affect both the mean state and variability in the tropical Pacific and imply increased ENSO amplitude but weakened AMO as Arctic sea ice and its interactions with the atmosphere diminish under global warming.
Brief introduction to the speaker: Dr. Dai is a Distinguished Professor of the Department of Atmospheric & Environmental Sciences at the University at Albany, State University of New York, USA. Dr. Dai obtained his PhD in Atmospheric Science from Columbia University in 1996. From 1997-2012, he worked at NCAR. In 2012, he joined the faculty of the University at Albany. He is an internationally renowned climate scientist with a focus on climate variability and change, Arctic climate, the global water cycle, hydroclimate, drought, the diurnal cycle, and climate data analysis. With more than 200 peer-reviewed publications, he has received 63,000-plus citations with an H-index of 91. He is one of the world’s top 1% Highly Cited Researchers. He served as the Chair of the Climate Variability and Change Committee and Editor of the Journal of Climate of the American Meteorological Society (AMS), and he is an AMS Fellow.