过去2000年冷暖变化的基本特征与主要暖期

根据近年国内外相关研究结果,分析了北半球与中国过去2000 年冷暖变化的阶段性,辨识了百年尺度暖期的起讫年代及其与20 世纪温暖程度的差别。结果表明:(1) 最近新建的多数北半球温度变化序列显示公元1-270 年温暖;271-840 年冷暖相间,但总体偏冷;841-1290年温暖;1291-1910 年寒冷;1911 年以后再次转为温暖;这些冷暖阶段虽分别与Lamb 指出的罗马暖期(约公元前1 世纪-4 世纪中期)、黑暗时代冷期(约4 世纪末-10 世纪前期)、中世纪暖期(约10 世纪中期-13 世纪末)、小冰期(约15-19 世纪) 以及20 世纪增暖大致对应,但各阶段的起讫时间与Lamb确定的时段存在一定差别。(2) 尽管过去2000 年冷暖变化过程及其变幅大小在中国境内各个区域间并不完全一致,但从全国平均看,中国与北半球百年尺度的冷暖波动阶段基本一致,仅起讫年代存在一定差异;其中公元1-200 年、551-760 年、941-1300 年及20世纪气候相对温暖,其他时段则相对寒冷。(3) 多数序列显示中世纪期间北半球的温暖程度至少与20 世纪相当。中国941-1300 年间的最暖百年和最暖30 年(暖峰) 的温度也略高于20 世纪,551-760 年间的最暖百年与20 世纪基本相当,但1-200 年间最暖百年的温暖程度则较20 世纪略低。

General characteristics of temperature change and centennial warm periods during the past 2000 years

The characteristics of warm/cold fluctuation for Northern Hemisphere (NH) and China during the past 2000 years were analyzed using the proxy-based temperature change series published recently. The duration of centennial warm periods before the 20th century and the difference between the warmth of the 20th century and the centennial warm periods that occurred prior to the 20th century were also investigated. The conclusions are summarized as follows: (1) Most of proxy-based NH temperature series show that the warm climate occurred in the periods of AD 1-270, 841-1290 and 1911-2000. In general, it was cool with multi-decadal temperature fluctuations from 271 to 840, and cold from 1291 to 1910. These centennial periods of warm/cold fluctuation over NH are corresponding to the Roman Warm Period (the 1st century BC to the mid-4th century AD), Dark Age Cold Period (the end of 4th century to the early of 10th century AD), Medieval Warm Period (the mid-10th century to the end of 13th century AD), Little Ice Age (the 15th to 19th century) and Warming Period in the 20th century illustrated by Lamb respectively. But they have different durations between the NH centennial warm/cold periods and those Warm/Cold Periods identified by Lamb. (2) The duration and amplitude of regional centennial phases of warm/cold fluctuation are different in China, but the timing of centennial periods of warm/cold over whole China, i.e. warm in AD 1-200, 551-760, 941-1300, 1901-2000 and cold in the others, which are consistent with that observed in NH approximately. (3) Most of proxy-based NH temperature change series show that the warmth in Medieval Warm Period is at least comparable to that during the Warming Period in the 20th century. The warmest 100-year and 30-year (i.e., warm peak duration) for whole China occurred in the periods of 941-1300 during the past 2000 years, which are slightly higher than in the 20th century respectively. Moreover, the temperature anomalies in the warmest 100-year and 30-year for whole China that occurred in the periods of 571-760 and 1-200 are comparable to and a little lower in the 20th century respectively.