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2022/04/22 14:00 Assistant Prof. Yu-Chiao Liang & Mr. You-Ting Wu（Department of Atmospheric Sciences, NTU）
Seminar
Poster： ╱ Post date：2022-04-19NCU IHOS Seminar Announcement
Speaker：Assistant Prof. Yu-Chiao Liang & Mr. You-Ting Wu
Place：S-325, Science Building 1
Abstract：
Title：The Arctic Amplification, and its Seasonal Migration, under Greenhouse Gases Forcings
Speaker：Assistant Prof. Yu-Chiao Liang & Mr. You-Ting Wu
Department of Atmospheric Sciences, NTU
Time：04/22（Fri.）14：00
Place：S-325, Science Building 1
Abstract：
Arctic amplification (AA), the larger warming of the Arctic compared to the rest of the planet, is widely attributed to the increasing concentrations of atmospheric greenhouse gases, and is caused by local and non-local mechanisms. In this study, we first examine AA, and its seasonal cycle, in a sequence of abrupt CO2 forcing experiments, spanning from 1 to 8 times preindustrial CO2 levels, using a state-of-the-art global climate model. We find that increasing CO2 concentrations gives rise to stronger Arctic warming but weaker AA, owing to relatively a weaker warming of the Arctic in comparison with the rest of the globe due to weaker sea-ice loss and atmosphere-ocean heat fluxes at higher CO2 levels. We further find that the seasonal peak in AA shifts gradually from November to January as CO2 increases, and that this seasonal shift in AA emerges in the 21st century in high-CO2 emission scenario simulations: during the early-to-middle 21st century AA peaks in November–December but the peak shifts to December-January at the end of the century. However, different global climate model presents large projection uncertainty in terms of the shifting months and strength. Decomposition on the total uncertainty into components associated with model structural differences, emissions scenario, and internal variability indicates that the model structural uncertainty dominates, and the scenario uncertainty is less important for AA than for other Arctic variables. The model uncertainty of the maximum value also shows seasonal shifting from autumn into winter. Our findings highlight the role of greenhouse gases forcing in affecting the seasonal evolution of amplified Arctic warming and the importance of model uncertainty in projected Arctic seasonality, which carries important ecological and socio-economic implications.
Last modification time：2022-04-19 AM 11:46
