Paleo and Polar Climate Brownbag Seminar - Yiyi Huang

Understanding the impacts of cloud-radiation feedback on Arctic sea ice changes at seasonal and interannual time scales

Yiyi Huang

University of Arizona

Abstract:

The cloud-radiation feedback is believed to be one of the critical reasons for the amplification of Arctic warming among all climate components. As the accelerated Arctic sea ice decline has been proven by satellite retrievals in past few decades, this study investigated the role of springtime (March-June) cloud-radiation feedback in modulating seasonal-to-interannual scale Arctic sea ice change utilizing an integrative analysis. Using NASA satellite observations, we found that increasing springtime cloud fraction and downward longwave flux at the surface tends to enhance sea ice melting in the Arctic via strong cloud warming effect, while surface shortwave fluxes play a more important role in determining September sea ice extent during late spring and early summer. The impacts of atmospheric physical and dynamical variables on the early and late initial sea ice melting events were also investigated for the selected years through the NASA MERRA-2 reanalysis. Based on CESM Large Ensemble (CESM-LE) simulations, we could better understand the Arctic cloud-radiation-sea ice feedback in the past, present and future and fully test the hypotheses, which is, the increasing springtime cloud and net surface radiation tends to enhance September sea ice retreat, leaving more open seas therefore higher atmospheric moisture content and more clouds in the following spring. This process will effectively create a positive feedback loop that potentially accelerates sea ice decline across interannual time scales.

Wednesday, 1 August 2018 12:00 - 1:00 pm Mesa Lab, 1850 Table Mesa Drive, Boulder, CO ML-245 – Chapman Room Seminar will not be webcast For more information, please contact Teresa Foster, teresaf@ucar.edu, 303-497-1741

Building:

Room Number: 
ML-245 Chapman Room
Will this event be webcast to the public by NCAR|UCAR?: 
No
Announcement Timing: 
Monday, July 9, 2018
Calendar Timing: 
Wednesday, August 1, 2018 - 12:00pm

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