Yi, S., Saito, Y., Chen, Z. and Yang, D.Y. 2006. Palynological study on vegetation and climatic change in the subaqueous Changjian (Yangtze River) delta, China, during the past about 1600 years. Geosciences Journal 10: 17-22.
The authors analyzed arboreal pollen, non-arboreal pollen and spores contained in a sediment core retrieved from the Changjiang prodelta (31°01.1'N, 122°47.0'E). This effort revealed, in their words, "relatively warm/wet conditions comparable to [the] Medieval Warm Period (AD 910-1085) with a strengthen[ed] summer monsoon." Based on the findings of others, they further state that "the mean temperature during this period was 1-2°C warmer than that of today." Since Yi et al.'s own work does not resolve actual temperature values, however, we classify this particular analysis as a Level 3 Study.