The potential connection between China surface air temperature and the Atlantic Multidecadal Oscillation (AMO) in the Pre-industrial Period

Abstract

One recent study by using instrumental records suggested the correlation between East Asian surface air temperatures (EATs) and the Atlantic Multidecadal Oscillation (AMO) reaches the maximum when the former leads the latter by 5–7 years. This seems to disagree with a previous well-realized point that the AMO modulates the decadal variation of EATs, since the atmosphere responds swiftly to sea surface temperature anomalies (SSTA) if therein. It implies that the AMO-EATs correlation should reach the maximum when they are simultaneous or the AMO leads EATs slightly, rather than that the EATs lead the AMO. Thus, this poses an issue about the reality of the newly found lead-lag correlation. Because the instrumental record in the natural climate system may be contaminated by human activities, the EATs-AMO lead-lag correlation derived from the instrumental records may not be a realistic connection of the natural climate system. Thus, whether the connection also exists in the proxies prior to the industrial is essential to answer the issue. In this study the EATs-AMO lead-lag connection is analyzed by using the reconstructed data in the last 500 years, together with the control experimental data with the prescribed pre-industrial forcing in a multiple of coupled climate system models, which attend the international CMIP5 program. The results suggest that the connection, the EATs lead the AMO, also exists in the period from the Little Ice Age (LIA) to the industrial, 1500–1860AD. Therefore, the connection may be realistic in the natural climate system. The mechanisms for the connection are then discussed briefly. The results from this paper provide some insights into the connection of the AMO with East Asian climate.