Deepening of Future Aleutian Low in Ensemble Global Warming Simulations with the Kiel Climate Model

• Published in: Ocean Science Journal
• Main Authors: Choi, Hwan Young, Lee, Ho Jin, Kim, Sang-Yeob, Park, Wonsun
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2020
• Subjects: Bering Sea; Okhotsk; Pacific; aleutian low; okhotsk sea; Sea ice; Aleutian Islands
• Online Access: https://oceanrep.geomar.de/id/eprint/49932/; https://oceanrep.geomar.de/id/eprint/49932/1/Choi2020_Article_DeepeningOfFutureAleutianLowIn.pdf; https://doi.org/10.1007/s12601-020-0017-7

We project changes of the Aleutian Low (AL) under global warming using ensemble simulations with a fully coupled ocean-atmosphere-sea ice model, the Kiel Climate Model (KCM). In the global warming simulations, the carbon dioxide (CO2) concentration increases by 1% per year from the preindustrial level of 286.2 ppm to a quadruple value in 140 years. Results from the 40 members of an ensemble simulation show an intensification of the AL such that ensemble mean North Pacific Index (NPI) is decreased by 2.71 hPa. It is also accompanied with an expansion of the AL to north. While the effect of weakened land-ocean thermal contrast and SST warming in the eastern tropical Pacific on the AL strength are relatively weak and marginally significant, sea ice loss in the marginal seas of the North Pacific, such as the Bering Sea and the Sea of Okhotsk, increases the surface air temperature and makes pressure lower over the Bering Sea and the Aleutian Islands. Especially, sea ice loss in the Okhotsk Sea drives the SLP change around the Aleutian Islands and contributes to the strengthening of the AL.