孢粉记录的岱海盆地1 500年以来气候变化

根据岱海盆地99A孔1.84m以上地层较高分辨率的孢粉资料,运用中国北方部分科属花粉-气候响应面定量恢复了岱海盆地1500aB.P.以来的七月平均气温和年均降水量。研究结果表明,岱海盆地的气候变化表现出明显的过渡带特征,1500aB.P.以来,七月平均气温除1500～1300aB.P.时段外,多低于现在;1500～980aB.P.岱海盆地的气候变化为温干-冷湿交替,980～400aB.P.以凉干-冷湿交替为特征,400aB.P.以来变为凉干-温湿的交替。980aB.P.以来,伴人植物草、荨麻花粉增加,表明人类活动加剧。是否是人类活动的加剧导致了400aB.P.以后岱海盆地气候变化格局的改变,值得进一步研究。

CLIMATE CHANGES OF DAIHAI BASIN DURING THE PAST 1 500 FROM APOLLEN RECORD

A higher resolution pollen record from core 99A reveals the variation of mean July temperatures and annual precipitations of Daihai basin during the past 1 500 by using pollen-climate response surfaces conducted by Sun Xiangjun et al. The result shows that the climate changed from warm and dry to cold and humid during the period of 1 500～980 aB.P. , from cool and dry to cold and humid during the period of 980～400aB.P., then from cool and dry to warm and humid since 400aB.P. The changes of climate pattern were different from that of East part of China and West part of China, and it showed the clear transitional situation. The mean July temperatures, except for 1 500～1 300aB.P., were lower than those of the present. Both Medieval Warm Period and Little Ice Period were present in the Daihai area, but the mean July temperatures were lower than those of the present during the Medieval Warm Period, and the mean July temperatures weren't the lowest period during the past 1 500aB.P. There is a clear increasing of Humulus and Urticaceae pollen percentages since 980aB.P., that probably referred to the intensity of human action. Whether the intensity of human actions could cause the changes of climate pattern should be further studied.