发表机构
Hankuk University of Foreign Studies; Jeju National University（韩国外国语大学; 济州国立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究基于韩国道路气象站数据，发现道路结冰前无一致临界减速信号，但结合前期气象条件可提升预警准确性，表明结冰主要由外部强迫驱动。
AI 中文摘要
临界减速（CSD）是指系统接近临界转变时，从扰动中恢复的速度减慢，该现象被广泛用于早期预警，但在快速变化的外部强迫作用下，环境转变中是否出现此类信号，很少通过观测数据进行检验。本研究利用韩国121个道路气象站的1分钟观测数据中的2427次结冰起始事件，发现此类信号并非一致地先于道路结冰出现。结冰从不同的前期地表状态开始，但起始时的条件连续变化，各路径之间的区分度较弱。起始时的冷剂量、沉积剂量和冻融累积量均超过非结冰对照时段，其中冷剂量的判别能力在30分钟或更短的衰减时间尺度上最高。然而，在CSD预期下方差和滞后1自相关的增加并不能区分结冰与对照时段；相同的方法在合成序列中恢复了这些增加（该合成序列具有下降的恢复率），并且这一零结果在127个独立站点的3091个事件中得到了重复验证。尽管如此，预测信息仍然存在：将近期变化和累积前期条件添加到当前条件中可提高判别能力，周围气象场使1至12小时预报窗口的ROC曲线下面积增加了0.030-0.032，并在3小时和6小时时减少了62-67%的误报。这些结果表明，道路结冰更符合近期气象强迫将路面推向结冰有利条件，而非内部稳定性逐渐下降，并指出了在外部强迫转变时早期预警应关注的方向。
英文摘要
Critical slowing down (CSD), the slowing of recovery from perturbations as a system approaches a critical transition, is widely used for early warning, but whether such signals appear in environmental transitions subject to rapidly changing external forcing has rarely been tested with observations. Here we show, using 2,427 icing-onset events in 1-min observations from 121 South Korean road weather stations, that such signals do not consistently precede road icing. Icing began from different prior surface states, but conditions at onset varied continuously with weak separation among pathways. Cold dose, deposition dose and freeze-thaw accumulation at onset exceeded those at non-icing control times, with cold-dose discrimination highest at decay timescales of 30 min or less. However, the increases in variance and lag-1 autocorrelation expected under CSD did not distinguish icing from control times; the same procedure recovered these increases in synthetic series with a declining recovery rate, and the null result was replicated for 3,091 events at 127 independent stations. Predictive information was nevertheless present: adding recent changes and cumulative antecedent conditions to current conditions improved discrimination, and surrounding meteorological fields increased the area under the ROC curve by 0.030-0.032 for forecast windows of 1 to 12 h and reduced false alarms by 62-67% at 3 and 6 h. These results suggest that road icing is more consistent with recent meteorological forcing moving the road surface into icing-favourable conditions than with a progressive decline in internal stability, and they indicate where early warning should look when a transition is externally forced.
Comments63 pages including Supplementary Information
