A multi‐model analysis of the East Asian monsoon changes in the Medieval Climate Anomaly and Little Ice Age

Abstract

AbstractUsing nine climate model simulations from the Paleoclimate Modelling Intercomparison Project Phase 3, the changes in the East Asian summer and winter monsoon, together with their associated atmospheric circulations in the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA), were investigated in this study. The East Asian summer monsoon strengthened (weakened) as a consequence of the increased (decreased) land–sea thermal contrast between the East Asian continent and the adjacent western North Pacific and South China Sea in the MCA (LIA). The East Asian winter monsoon (EAWM) changes varied across models, and differences were shown between the low latitudes and mid‐to‐high latitudes of the EAWM region. In the northern area, the EAWM intensified slightly due to a reinforced Aleutian Low during the MCA and decreased slightly because of the suppression of the Siberian High and the weakening and northward shift of the Aleutian Low during the LIA. In contrast, there are large inconsistencies among models during both periods in the southern EAWM region. Our results imply that model improvement is needed to reproduce the complex interacting processes over the low latitudes of East Asia.