宋元时期中国西北东部的冷暖变化

TEMPERATURE VARIATIONS DURING THE SONG AND YUAN DYNASTIES (960～1368A. D. )IN THE EASTERN PART OF NORTH WEST CHINA

根据历史文献中的作物种植界线、种植制度变化、植物及异常气象水文物候等记载,并辅以树轮、湖泊沉积等自然证据指示的冷暖变化状况,分析了宋元时期(960～1368A.D.)我国西北地区东部的冷暖变化特征。主要结论是:960A.D.前后,西北东部地区冷暖程度与今(即1951～1980年)基本一致;960s～1040s,气候逐渐增暖;1040s～1110s,气候较今暖;1110s以后,气候转冷;12世纪末,气候又再次明显转暖;1260A.D.之后,温度下降,自13世纪末进入寒冷期。西北东部的这一冷暖变化过程不但与毗邻地区湖泊、特别是树轮等所指示的冷暖变化过程较为一致,而且与中国东部地区的冷暖变化也基本一致,但13世纪后期的降温幅度较中国东部更为明显。

The eastern part of North West China includes the middle and north part of Shaanxi Province and Ningxia Autonomous Region, the southeast part of Gansu Province and the west part of Henan Province. Temperature variations during the Song and Yuan Dynasties（960-1368A. D.） in this region were estimated in terms of historical records and natural evidence such as north winter wheat planting limit boundaries, farming systems, extreme weather,phenological change,tree rings, and lake sediments. As a result, such a picture of climate variations was revealed： the climate around 960A. D. was similar to that during 1951 - 1980; the climate during 960s - 1010s became gradually warm; the temperature during 1040s - 1110s was at least 0.5℃ higher than that of 1951 - 1980; the climate after 1110s became cold; the temperature during the middle of 12^th century,especially in the period of 1170s - 1180s was 0.8-1.2℃ lower than that of 1951-1980 ; the climate in the end of 12^th century became again warm and the temperature was 1.4℃ higher than 1951 - 1980; and the climate after 1260A. D. began becoming cold and by he end of 13^th century there was a cold time. The climate picture can be correlated not only with cold-warm changes, but also with those in East China. The difference is only that the temperature decrease in this region was more significant than that in East China. It could be related to the geographical location of the eastern part of North West China. Perhaps, this region is very sensitive to global climatic change. In addition, because of very limited records,temperature reconstruction series has large uncertainty and time resolution was varies from 10 to 50-years.