With global climate change, compound extreme weather events are occurring more frequently in many parts of the world. Air temperature and precipitation are the most important weather elements that influence maize growth and yield formation, especially under rainfed cultivation. A consensus has developed that combined temperature and precipitation stresses cause more serious damage to crops than a single stress. However, differences in the effects of varying compound extreme temperature (hot or cold) and precipitation (dry or wet) events on maize yield remain unclear. Daily observations during the period 1991–2020 from 141 meteorological stations in North China were used to identify compound hot–dry, cold–dry, hot–wet, and cold–wet events during the summer maize growing season based on the standardized precipitation index (SPI) and standardized temperature index (STI). Three-dimensional joint cumulative probability distribution functions were constructed using vine copulas to assess the probability of yield loss rate (YLR) limited by different compound events. The results showed that the frequency and spatial extent of heat-related compound events in the 2010s were much higher than in previous decades, while those for compound cold-wet events were much lower. In contrast, there was no marked difference in the occurrence of cold–dry events among the different decades. Summer maize in North China has a higher probability of yield reduction with increases in temperature and precipitation stress, mainly because of increases in moderate and severe yield losses. Compared with heat or cold during the growing season, an increase in the severity of the dry or wet will lead to a more significant increase in the YLR, especially for compound cold–dry and cold–wet events. The occurrence of cold–wet and hot–dry events has a higher probability of being linked to severe yield loss than cold–dry and hot–wet events in North China. Our findings can assist decision-makers and growers in better understanding compound event occurrence characteristics and their potential effects on maize yield in North China, which is valuable for minimizing production risks.

中文翻译：

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不同复合极端温度和降水事件对华北夏玉米产量的影响差异


随着全球气候变化，复合极端天气事件在世界许多地方发生的频率越来越高。气温和降水是影响玉米生长和产量形成的最重要天气因素，尤其是在雨养耕作下。已经形成共识，温度和降水胁迫相结合对作物造成的损害比单一胁迫更严重。然而，不同的复合极端温度（热或冷）和降水（干或湿）事件对玉米产量的影响差异仍不清楚。利用华北地区 141 个气象站 1991—2020 年期间的逐日观测数据，基于标准化降水指数 （SPI） 和标准化温度指数 （STI） 确定夏玉米生长季的复合热-干、冷-干、热-湿和冷-湿事件。使用 vine copulas 构建三维联合累积概率分布函数，以评估受不同化合物事件限制的产量损失率 （YLR） 概率。结果表明，2010 年代与热相关的复合事件的频率和空间范围远高于前几十年，而复合冷湿事件的频率和空间范围远低于前几十年。相比之下，不同年代的干寒事件发生率没有显著差异。华北地区夏玉米随着温度和降水胁迫的增加而减产的可能性更高，主要是由于中度和重度产量损失的增加。与生长季的高温或低温相比，干旱或潮湿严重程度的增加将导致 YLR 更显着地增加，尤其是对于复合冷-干和冷-湿事件。 与华北地区寒-干和热-湿事件相比，寒-湿-热事件的发生与严重产量损失有关的可能性更高。我们的研究结果可以帮助决策者和种植者更好地了解复合事件发生特征及其对华北玉米产量的潜在影响，这对于最大限度地降低生产风险很有价值。