Mid-Holocene East Asian summer climate as simulated by the PMIP2 models

In the present study, datasets derived from twelve coupled ocean–atmosphere general circulation models (OAGCMs) in the Paleoclimate Modelling Intercomparison Project phase two were used to analyze the East Asian summer climate during the mid-Holocene (about 6000 calendar years ago). On the whole, the OAGCMs reproduced warmer and wetter summer climate conditions in East Asia during the mid-Holocene. The multi-model ensemble showed that in East Asia, the regionally-averaged summer surface air temperature (SAT) increased by 0.89 °C, summer precipitation was 5.8% higher, and an obviously strengthened southerly wind corresponded to a strong summer monsoon in the mid-Holocene when compared to preindustrial levels. The data-model comparison in China reveals a good agreement between the OAGCMs' results and the reconstructed changes in the summer SAT in East China during the mid-Holocene. In North China, the simulated SAT anomalies are 0.5 °C lower overall than reconstruction. In contrast, the OAGCMs fail to capture the strongest warming in the southern Qinghai–Tibetan Plateau. On the other hand, the simulated precipitation agrees well with proxy data except for in the central parts of China, where the simulated summer precipitation disagrees in sign with reconstruction. In addition, there is a large spread among the simulations, particularly over and around the Qinghai–Tibetan Plateau, and inter-model discrepancies are larger for precipitation than for SAT as a whole.