Impact of Antarctic meltwater forcing on East Asian climate under greenhouse warming

Ji-Hoon Oh1, Wonsun Park2, Emilia Kyung Jin3, Hyung-Gyu Lim1,4, Kyung Min Noh1 and Jong-Seong Kug1, (1)Pohang University of Science and Engineering, Pohang, South Korea, (2)GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany, (3)Korea Polar Research Institute, Incheon, Korea, Republic of (South), (4)AOS program in Princeton Univ / NOAA-GFDL, Princeton, NJ, United States
Abstract:
In recent decade, massive Antarctic ice-shelf collapse has been frequently reported. That releases the enormous meltwater into the Antarctic Ocean. The previous studies suggested that the increase of Antarctic meltwater could delay global warming in the Southern Hemisphere. However, the impact of enormous meltwater on the Northern Hemisphere climate is not well comprehended. In this study, we employed Kiel Climate Model (KCM) to investigate the impact of meltwater in global warming via the idealized Antarctic meltwater forcing simulation. We found that the Antarctic meltwater accelerates additional warming in the East Asia while the meltwater delays the global warming in the Southern Hemisphere as shown as previous studies. In this experiments, the Antarctic meltwater leads to the positive sea-ice concentration anomaly in the Antarctic Ocean, which strongly reduces surface air temperature via the positive ice-albedo feedback. Subsequently, the cold anomaly in the Southern Hemisphere enhances the meridional temperature gradient, which leads to southward energy transport. That releases northward shift of Inter-Tropical Convergence Zone (ITCZ), and in turn the negative precipitation anomaly in the Western North Pacific. This negative precipitation induces the Gill-type Rossby wave response, which develops cyclonic flow in the Western North Pacific upper troposphere. That develops Kuroshio Anticyclone via the Rossby wave propagation. In this study, we suggest a possible mechanism of interaction between both Hemispheres, that would alter the acceleration in the East Asia warming trend.