Initiation of East Asia monsoon failure at the climate transition from the Medieval Climate Anomaly to the Little Ice Age

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

“…The EASM intensity during the last millennium has been reconstructed from multiple types of geological archives, including stalagmite records (Wang et al ., ; Hu et al ., ; Zhang et al ., ; Tan et al ., ; Zhao et al ., ), fossil pollen and ostracods from lake sediments (Yan et al ., ; Chen et al ., ; Li et al ., ; Yamada et al ., ) and marine sediments (Lee and Park, ; Deng et al ., ). Most of these reconstructions are indicators of precipitation variation, and they demonstrated a degree of regional feature (Figure b,c).…”

“…The rectangles are the same as in Figure . The locations of Dongge Cave (Wang et al ., ), Heshang Cave (Hu et al ., ), Wanxiang Cave (Zhang et al ., ), Huangye Cave (Tan et al ., ), Dongdao Island (Yan et al ., ), Gonghai Lake (Chen et al ., ), core TY08PC1 (Lee and Park, ), Yelang Cave (Zhao et al ., ), Qionghai (Deng et al ., ), Mulyoungari Swamp (Park et al ., ) and Nakaumi Lake (Yamada et al ., ) are marked, with red, blue and purple representing strong, weak and no obvious changes in EASM during the corresponding periods, respectively [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…Generally, proxy sites located in the northern monsoonal region showed a stronger EASM during the MCA than during the LIA (Hu et al ., ; Zhang et al ., ; Tan et al ., ; Chen et al ., ; Li et al ., ), which is consistent with the finding of multiple simulations, whereas those located in the southeastern region exhibited insignificant EASM differences between the two periods but centennial scale variations (Zhao et al ., ) or an increasing trend beginning in the late MCA (Wang et al ., ). Moreover, two lake sediments (Park et al ., ; Yamada et al ., ) and one marine sediment (Lee and Park, ) showed conflicting changes around South Korea and southwest Japan. Park et al .…”

“…It is widely accepted that ENSO plays a role in influencing the EASM; the inconsistent precipitation pattern might be generated from the different sea surface temperature patterns and also ENSO-related physical processes, for example, the Indo-western Pacific ocean capacitor (Xie et al, 2016), simulated from model to model. The EASM intensity during the last millennium has been reconstructed from multiple types of geological archives, including stalagmite records (Wang et al, 2005;Hu et al, 2008;Zhang et al, 2008;Tan et al, 2010;Zhao et al, 2015), fossil pollen and ostracods from lake sediments (Yan et al, 2011;Chen et al, 2015;Li et al, 2017;Yamada et al, 2019) and marine sediments (Lee and Park, 2015;Deng et al, 2017). Most of these reconstructions are indicators of precipitation variation, and they demonstrated a degree of regional feature (Figure 5b,c).…”

“…Reconstruction studies regarding the EASM suggest that East Asia generally experienced a stronger EASM during the MCA than during the LIA (Wang et al ., ; Hu et al ., ; Zhang et al ., ; Li et al ., ). By comparing the EASM evolution with other proxy data, it is further proposed that external forcing factors such as solar activity (Wang et al ., ; Zhang et al ., ; Li et al ., ) and internal variability modes such as the Asia‐Pacific Oscillation (Fang et al ., ) and Pacific Decadal Oscillation (Lee and Park, ; Zhao et al ., ) may affect the EASM variation. On the other hand, the sequences of the Holocene EAWM are less well established than those of the EASM because of unsuitable archives and proxies (Sagawa et al ., ), and discrepancies are evident among different reconstruction results (Xiao et al ., ; Liu et al ., ; Sagawa et al ., ; Tu et al ., ; Li et al ., ).…”