The historical to future linkage of Arctic amplification on extreme precipitation over the Northern Hemisphere using CMIP5 and CMIP6 models

Arctic warming played a dominant role in recent occurrences of extreme events over the Northern Hemisphere, but climate models cannot accurately simulate the relationship. Here a significant positive correlation (0.33–0.95) between extreme precipitation and Arctic amplification (AA) is found using observations and CMIP5/6 multi-model ensembles. However, CMIP6 models are superior to CMIP5 models in simulating the temporal evolution of extreme precipitation and AA. According to 14 optimal CMIP6 models, the maximum latitude of planetary waves and the strength of Northern Hemisphere annular mode (NAM) will increase with increasing AA, contributing to increased extreme precipitation over the Northern Hemisphere. Under the Shared Socioeconomic Pathway SSP5-8.5, AA is expected to increase by 0.85 °C per decade while the maximum latitude of planetary waves will increase by 2.82° per decade. Additionally, the amplitude of the NAM will increase by 0.21 hPa per decade, contributing to a rise in extreme precipitation of 1.17% per decade for R95pTOT and 0.86% per decade for R99pTOT by 2100.