1736年以来西安气候变化与农业收成的相关分析

Climate Change and Harvest in Xi'an since 1736: The High-resolution Data Derived from the Archives in the Qing Dynasty

基于清代雨雪与农业收成等档案记载及现代气象观测记录,根据西安冬季降雪与平均气温之间的统计关系、降水入渗与水量平衡模型,分别重建了西安1736～2000年冬季平均气温与4季降水序列,并分析了该地区气候变化特征及其对1736～2000年农业收成的影响.主要结论如下:(1)西安的冷暖变化存在明显的百年际波动:其中18世纪相对温暖,19世纪寒冷,20世纪又转为温暖,且增暖趋势极为明显.(2)西安的降水变化存在明显的年代际波动.自1736年以来,共经历了6个多雨期与7个少雨期,其中多雨期的平均雨量比少雨期多16%.(3)气候变化对农业收成的影响极为明显.其中夏季降水量与秋收关系显著,而夏收又与前一年秋～当年春季的降水明显相关,且大多数严重歉收年均由降水明显偏少而致.虽然温度的年际变化与收成没有显著的联系,但温度年代际变化,即气候的冷暖阶段变化却与收成的阶段性变化关系密切.

Based on snow, rainfall and harvest archives records in the Qing Dynasty (1644-1911 AD), the modern meteorological observation data, the annual winter mean temperature and seasonal precipitation series from 1736 to 2000 and the series of harvest in summer and autumn from 1736 to 1910 are reconstructed. Meanwhile, the characteristics of climate change and the relationship between climate change and harvest are analyzed by using the high-resolution data. The results show: (1) Warm and cold changes in Xi'an have obvious inter-centennial fluctuation. Climate is relatively warm in the 18th century and cold in the 19th century, but turns warm with a rapid warming trend in the 20th century. (2) Precipitation changes have obvious inter-decadal fluctuation, experiencing six rainy periods and seven drought periods in Xi'an since 1736, in which the mean precipitation in the rainy periods is 16% more than that in drought periods. (3) The coefficients between the precipitation from June to August and the harvest in autumn are well correlated, and the precipitation during the period from September to May and the harvest in summer are remarkable.