The Key Role of Atlantic Multidecadal Oscillation in Minimum Temperature Over North America During Global Warming Slowdown

摘要

Daily minimum temperature (Tmin) is an important variable in both global and regional climate changes, and its variability can greatly affect the ecological system. In the early 21st century, warming slowdown is seen over the North Hemisphere and North America is one of the major cooling centers. In this study, we found that Tmin experienced an obvious decline in North America during warming slowdown period. Such Tmin decline is closely related to the Atlantic Multidecadal Oscillation (AMO); the correlation between the decadal components of Tmin and AMO reached 0.71 during 1950–2014. According to composite analysis, the AMO on the positive (negative) phase takes two low‐pressure (high‐pressure) systems in the northeastern Pacific and the North Atlantic at night, accompanied by cyclonic (anticyclonic) circulations and warm (cold) advection in North America. Therefore, the analyses conclude that the Tmin decline during warming slowdown period is a result of the synchronous decrease of the AMO. The results emphasize the key role of AMO on the decadal variation of Tmin in North America.