Impact of Antarctic Meltwater Forcing on East Asian Climate Under Greenhouse Warming

• Published in: Geophysical Research Letters
• Main Authors: Oh, Ji‐Hoon, Park, Wonsun, Lim, Hyung‐Gyu, Noh, Kyung Min, Jin, Emilia Kyung, Kug, Jong‐Seong
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU (American Geophysical Union) 2020
• Subjects: Antarctic; Pacific; Southern Ocean; Antarc*; Ice Sheet
• Online Access: https://oceanrep.geomar.de/id/eprint/51101/; https://oceanrep.geomar.de/id/eprint/51101/1/2020GL089951.pdf; https://doi.org/10.1029/2020GL089951

Key Points: • Antarctic meltwater forcing induces an overall global cooling but regional warming in East Asia • Antarctic meltwater forcing can shift the Intertropical Convergence Zone northward and suppress convection over the Western North Pacific • Suppressed convection in the Western North Pacific is responsible for the regional warming of East Asia via atmospheric teleconnection. In recent decades, Antarctic ice sheet/shelf melting has been accelerated, releasing freshwater into the Southern Ocean. It has been suggested that the meltwater flux could lead to cooling in the Southern Hemisphere, which would retard global warming and further induce a northward shift of the Intertropical Convergence Zone (ITCZ). In this study, we use experimental ensemble climate simulations to show that Antarctic meltwater forcing has distinct regional climate impacts over the globe, leading in particular to regional warming in East Asia, which offsets the global cooling effect by the meltwater forcing. It is suggested that Antarctic meltwater forcing leads to a negative precipitation anomaly in the Western North Pacific (WNP) via cooling in the tropics and the northward shift of the ITCZ. This suppressed convection in WNP induces an anticyclonic flow over the North Pacific, which leads to regional warming in East Asia. This hypothesis is supported by analyses of interensemble spread and long-term control simulations.