Climate in China during the four special periods in Holocene

Characteristics of temperature over China during the four special periods in the Holocene, i.e. the Megathermal, the Medieval Warm Period, the Little Ice Age and the Modern Warm Period, are analyzed. The Megath-ermal period was 8.5-3.0 kaBP,the maximum temperature appeared at about 5.5-6.0 ka and 7.0 kaBP, while the temperatures were about 2t above the average of the latest one hundred years. During the Medieval Warm Period, from the late 9th century to the 13th century, the temperatures were warmer over eastern China. Some maximum temperatures were close to the mean value in 1880s-1970s. However, the climate in the 12th century was cold. Over the west part of China, temperatures did not show the same features as that over the east except the moderate warmth appeared during the second half of the 9th century. There were five cold spells in China during the last millennium; in the early 12th, 14th and 16th centuries, the late of 15th century, the 17th and 19th centuries. In these cold periods, the last three spells can be considered as the Little Ice Age of China, the minimum of temperature anomaly was below - 1.0℃ and - 0.5℃ for the 10 years' and 30-50 years' mean respectively. The 20th century was the wannest in the last 12 centuries, and was 0.5t wanner than the last 1200 year's mean. During the last one hundred years, the warmest period appeared in 1920s-1940s, but the highest annual temperature occurred in 1998 in which the temperature anomaly was +1.38℃ with respect to the mean temperaure of 1961s-1990s.