981~1040年开封牡丹观赏记录及其对北宋气候冷暖变化的指示

丰富的历史文献是我国过去全球变化研究的优势条件，然在"中世纪暖期"前期，中国东部地区此类别资料中客观而具有高置信度的物候信息仍有深入挖掘的余地。为弥补这一缺憾，根据5种历史文献记载的河南开封、洛阳地区981~1040年的38条赏花日期记录，重建了这60年间开封牡丹盛花期的变化，并将其与其他文献证据、温度重建序列所反映的气候冷暖变化特征进行了对比，检验了资料的准确性。结果显示：1）开封981~1040年的气候可能略暖于现今，牡丹盛花期的均值4月21日比现今早1.0天；2）当时开封牡丹盛花期的变幅（4月11~30日）基本上未超过现代；3）牡丹盛花期呈现出0.4天/10年的微弱提前趋势，说明当时气候虽然总体上偏暖，但增温趋势不明显；4）牡丹盛花期的年代际变化可划分为平均比现今晚1.6天的981~994年、早2.8天的995~1016年、晚2.9天的1017~1030年和早6.0天的1031~1040年这4个阶段，说明当时总体上略比现今温暖的气候并不是持续温暖的；5）序列与夏秋税征收日期、水稻种植范围、柑橘分布北界、植物二次开花与再实、冬雷等其他文献证据所指示的期内各阶段气候状况比较吻合，也与中国东部及邻近地区的其他温度重建序列在冷暖变化过程上异同互现。该结果有助于更为准确地诊断中国东部"中世纪暖期"的阶段性气候变化特征，为下一步集成重建中国东部地区在"中世纪暖期"时段更长、结果不确定性更小的温度序列以及定量分析当时气候变化与社会经济兴衰之间的关系提供重要依据。

Peony-appreciating dates recorded in historical documents around Kaifeng in Henan Province and their indications to climate variations during 981~1040 A.D.

Abundant historical references are great advantage in the research field of past global changes in China. However, in the early period of the Medieval Warm Period, there is still room for further exploration of objective and high confidence phenological information in Eastern China. In order to fill in this gap, we extracted 38 peony(Paeonia suffruticosa) flower appreciation dates from five kind of historical documents, during 981~1040 A.D., around Kaifeng(34.80°N, 114.32°E) and Luoyang(34.68°N, 112.44°E) in Henan Province. On the basis of the panel data model reflecting the quantitative relationship between spring temperatures and peony full-bloom dates, full-bloom-date variations of peony in Kaifeng at that time were reconstructed. This reconstructed sequence was analyzed by use of the Shapiro-Wilk normality test, Theil-Sen estimator, Mann-Kendall trend test, and the FFT low-pass filter smoothing. The sequence was also compared with other literature evidences and temperature reconstruction series in China.