Classification of Cold Air Outbreaks in East Asia and Potential Stratospheric Harbingers

Abstract Cold air outbreaks (CAOs) enormously influence agriculture, environment, industry, and other socioeconomic activities in East Asia. This study objectively identifies and categorizes CAOs in East Asia by employing 3‐dimensional CAO detection algorithm and k‐means clustering method. The analysis identifies a total of 106 CAOs from 1979 to 2017, which are classified into three distinct types based on core cold anomaly positions: South, Mixed, and North types. The South type, with the fewest occurrences and shortest lifetime, exhibits a weak warm lobe over Europe and northern Asian coast with the coldest anomalies over southern China. The Mixed type, most frequent and longest‐lived, features the most extensive and coldest anomalies across Eurasia uniformly distributed over East Asia. The North type shows the coldest anomalies in northeast Asia with weaker effects in southern East As…