历史寒冬极端气候事件的复原研究——1670/1671年冬季严寒事件

A Study of the Severest Winter of 1670/1671 over China as an Extreme Climatic Event in History

1670/1671年冬季中国东部地区异常严寒。本文依据历史文献记载复原该寒冬实况,绘制了雪、冰、冻雨和动植物冻害的地域分布图,连续降雪日数分布图和最大积雪深度分布图,可见河流封冻南界达27?N,是小冰期我国河流封冻的最南位置。依据各地寒冷记录和江河封冻、树木冻死的临界温度条件定量推断各地极端最低温度值,指出1671年1月湖南衡山县的最低气温低至-15℃,比现代(1951—2000年)极端最低气温记录低7℃。1670/1671年寒冬之后华北、长江中下游地区夏季高温酷暑。这是小冰期寒冷阶段的典型寒冬之一,又是冬季严寒、夏季异常炎热的罕见个例。

The winter of 1670/1671 was abnormal severe cold over eastern China. In this study the coldness situation of the winter was reproduced by means of historical literature records using our historical climate data system. A map of coldness records distribution including heavy snow, frost, trees and bamboo freeze injuries, and the maps of the depth of snow cover and of the snow days were plotted. It is shown that the south boundary of river freeze-up reached south to 27?N, which is the most southern location of river freeze-up in historical records of China, and days with snow lying in South China were never seen in the modern times. Based upon the coldness records of places and the critical temperatures necessary for river freeze-up and tree winterkill, the extreme minimum temperatures were deduced quantitatively. It indicateded that the deduced minimum temperature in Hengshan county of Hunan province in January 1671 was ?15 ℃ , which is 7 ℃ lower than the absolute minimum temperature record in the modern times (1951-2000). Following the severe winter, there was a large range of severe drought, which is different from the usual climate (a large range of rain in summer), and a hot summer in northern China and middle-lower reach of the Yangtze River. So that a rare great amplitude of temperature occured in that year. 1670/1671 winter was in the Maunder minimum solar activity period. There were few large volcano activities in the world ahead of the severe winter. As for the sea temperature, there was a very strong El Ni?o event in 1671, and 1670 was a non-El Ni?o year before the El Ni?o events. This severe winter corresponded to the warmest phase of sea temperature in the equatorial east Pacific Ocean. So, the winter of 1670/1671 is a typical severe winter in the Little Ice Age of China. It is a rare case of severe cold winter with abnormal hot summer, and also a special case of a wide range of severe drought following a severe cold winter.