基于1873年以来器测气温的二十四节气气候变化

2000多年来二十四节气已广泛用于指导人们生产和生活。然而传统二十四节气的应用意义在当前全球变暖背景下正在发生变化。气候学二十四节气的提出赋予了二十四节气动态变化的内涵，有利于更好地发挥其现实指导作用。本文利用北京观象台1940~2017年和上海徐家汇站1873~2017年均一化的逐日气温观测序列，分析了近百余年二十四节气气候变化特征。结果显示，北京1941~2016年和上海1874~2016年的年平均气温和二十四节气气温都呈现变暖趋势，导致早春到初夏阶段的气候学节气呈现提前的趋势，而夏末到初冬阶段的节气呈现推迟的趋势；这些趋势大部分是统计显著的。北京和上海的极端冷事件（以大寒标准定义）均呈现显著的减少趋势，上海的极端热事件（以大暑标准定义）呈现显著的增多趋势。除了长期趋势之外，上海极端热事件频数和夏季平均气温演变中都存在明显的60~80年周期的多年代际变率，和大西洋多年代际振荡相关。相比以往基于1960年以来的观测所做的二十四节气气候趋势分析，本文揭示了更完善的长期气候变化特征，有助于从精细化的季节循环演变角度丰富关于近代中国气候变暖的认识，为适应气候变化提供科学基础。

Climatic Changes in the Twenty-Four Solar Terms Based on Temperature Observations Back to 1873

Twenty-four Solar Terms (24STs) have been widely used for guiding human activities in China over more than 2000 years. However, the implication of the conventional 24STs has been changing under global warming. The climatic 24STs proposed recently impose a time-varying characteristic on the conventional 24STs, thus they can better serve as guidance for people under current situation. Previous studies only focused on linear trend of the 24STs since 1960. In this study, climatic changes in the 24STs back to 1873 are analyzed based on homogenized daily temperature series at Beijing station for the period 1940-2017 and at Shanghai station for the period 1873-2017. The results show that the annual mean temperature as well as temperatures of the 24STs at Beijing station for the period 1941-2016 and at Shanghai station for the period 1874-2016 all show warming trends, thus resulting in advancing trends during the warming stage (around spring) and delaying trends during the cooling stage (around autumn) in the timings of the climatic Solar Terms in the seasonal cycle. Most of these trends are statistically significant. The occurrence of extreme cold days shows a significant decreasing trend at both stations of Beijing and Shanghai, whereas the occurrence of extreme hot days at Shanghai station shows a significant increasing trend. In addition to the long-term trend, there exists apparent multi-decadal variability with a period of 60-80 years in both the occurrence of extreme hot days and summer temperature at Shanghai station, which is correlated with the Atlantic Multi-decadal Oscillation. These results can provide an important scientific base for climate change adaptation and benefit the understanding of modern climatic warming in China from a perspective of fine evolution of the seasonal cycle.