Reconstruction of weather processes in eastern China in winter of 1742—1743: A study of historical extreme cold winter events in a relatively warm background

The study of extreme climate events in historical periods can provide valuable long-term comparisons and references for the study of modern extreme climate events. The winter of 1742—1743 was an extreme cold winter event under a relatively warm background during the LIA (Little Ice Age), with both its climatic context and cold intensity more comparable to modern extreme cold winter events. Using high-resolution historical documents as primary proxy data, including Qing dynasty archival reports and local chronicles, the daily-to-subdaily weather processes of the winter of 1742—1743 across eastern China were reconstructed in detail. There were at least 13 recognizable cold air processes recorded in this winter, including 10 cold wave processes. This number exceeds modern recorded extremes, characterizing the winter of 1742—1743 as a typical multi-cold-wave winter. In terms of intensity, individual cold waves this year were generally weaker than those during the coldest phases of the LIA but closer in strength to modern extreme cold outbreaks. Climatic background analysis suggests the influence of reduced Barents—Kara Sea ice, a moderate positive NAO phase, and a contemporaneous La Niña event—a combination resembling the setting of the 2007—2008 winter. Comparatively, the winter of 1742—1743 aligns closely with 2007—2008 in terms of synoptic progression and snowfall patterns, while its frequency of cold waves and seasonal cold severity show similarities to 1968—1969, and the intensity of individual cold air events echoes that of January 2016. The reconstruction method used in this article can also be extended to the reconstruction of other winter weather processes during the pre-measurement period, which can be compared with modern cases or simulation results at a more detailed level.