长江中下游地区1620年的极端冷冬研究

The extreme cold winter of 1620 in the middle and lower reaches of the Yangtze River

根据历史文献记载,分析了长江中下游地区1620年冬季的积雪特征与寒冷程度;估算了1620年长江中下游地区及9个地点相对于1961-1990年的冬季气温距平。结果表明:①1620年长江中下游地区冬季积雪期在30~100日之间,其中荆州积雪期最长,可能达百日之久;合肥、霍山、南京、巢湖等地积雪平均达70日左右;安庆、武汉、常德、长沙、景德镇等地积雪40~60日不等;苏南、上海等地积雪日数相对较少,也达30日左右。②1620年长江中下游地区极端寒冷,冬季的区域平均气温较现代(1961-1990年)低约4.4℃;其中景德镇的冬季气温负距平最大,较现代平均低约5.7℃;其次为霍山、合肥、常德、武汉和上海,其冬季气温距平在-5^-4℃之间;长沙冬季气温负距平虽相对最小(低约3.6℃),但仍远低于器测时期的极端最低值。

Climate extremes have become a hot topic in the field of climate change research.In this study,the snow-cover days over the middle and lower reaches of the Yangtze River(MLRYR) in the winter of 1620 were extracted from Chinese historical documents and archives.Using these records,the winter temperature anomalies(with respect to the 1961-1990 mean) of 9 stations were estimated based on the relationship between winter temperature and snow-cover days during the period with available instrumental observations.The regional winter temperature anomaly over the MLRYR was also estimated through stepwise regression.The results show that:(1) The regional mean snow-cover days for the middle and lower reaches of the Yangtze River were about50 days,with high spatial variability.Snow-cover days ranged from 30 in Shanghai to 100 in Jingzhou,and the average snow-cover days were approximately 70 days in Hefei,Huoshan,Nanjing,Chaohu,among others in the region.Snow-cover days in Anqing,Wuhan,Changde,Changsha and Jingdezhen were 40 to 60,while the least snow-cover days of about 30 were found in Shanghai and southern Jiangsu Province.(2) It was extremely cold in the winter of 1620,and the regional mean winter temperature was estimated to be lower by approximately4.4℃ than that in the period of 1961-1990.The maximum(coldest) winter temperature anomaly occurred in Jingdezhen,with winter temperature anomaly of about 5.7℃ lower than the reference period.The next were Huoshan,Hefei,Changde,Wuhan and Shanghai,with the winter temperature anomalies ranging between-5 and-4℃.Nanjing,Anqing and Changsha experienced smaller negative anomalies,ranging from-4 to-3℃.The minimum(warmest) winter temperature anomaly was detected in Changsha,but it was still much lower than the coldest record during the observational period.