Whether hydroclimatic extremes cause yield losses or failures not only depends on their intensity but also on local environmental conditions. These conditions shape the capacity to buffer climatic shocks and thus necessitate a regionally specific impact assessment and adaptation planning. However, the degree to which different environmental conditions affect climate impacts on yields and its spatiotemporal variability across Germany is relatively unknown. In this study, we use a regression-based crop-climate modelling approach for 71 regions, classified according to soil and climate characteristics and investigate region-specific vulnerabilities of winter wheat yields to hydroclimatic extremes for the period 1991–2019. We account for the co-occurrence of temperature and moisture impacts (i.e. compound effects) as well as for local soil-climate conditions. On average, our models can explain approx. 67 % of past winter wheat yield variations. Despite the rather homogeneous climate in Germany, the results reveal clear geographic differences across different soil-climate regions. While the north-eastern regions show a clear dominance of drought impacts, southern regions show stress due to moisture excess. Heat impacts can clearly be linked to the warm regions along the western part of the country. Overall, compound dry-hot extremes pose the strongest and most widespread risk for winter wheat yields in Germany, being responsible for approx. 38 % and in some regions for up to 50 % of past yield variations. Based on the identified regional differences in hydroclimate susceptibility, we can define four geographic risk clusters, which exhibit vulnerability to climatic extremes such as summer droughts, winter droughts, summer heat waves, and winter moisture excess. The identified risk clusters of heat and moisture stresses could inform regional-specific adaptation planning.

中文翻译：

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德国冬小麦对气温、降水或复合极端天气的脆弱性是由土壤气候带决定的


极端水文气候是否会导致产量损失或失败，不仅取决于其强度，还取决于当地的环境条件。这些条件塑造了缓冲气候冲击的能力，因此需要针对特定区域的影响评估和适应规划。然而，不同环境条件对气候对产量的影响程度及其时空变率在德国相对未知。在这项研究中，我们对 71 个地区使用基于回归的作物气候建模方法，根据土壤和气候特征进行分类，并调查了 1991-2019 年期间冬小麦产量对极端水文气候的特定地区脆弱性。我们考虑了温度和湿度影响（即复合效应）的共存以及当地的土壤气候条件。平均而言，我们的模型可以解释大约 67% 的过去冬小麦产量变化。尽管德国的气候相当均匀，但结果揭示了不同土壤气候区域之间的明显地理差异。虽然东北地区在干旱影响方面明显占主导地位，但南部地区由于水分过剩而表现出压力。高温影响显然与该国西部的温暖地区有关。总体而言，复合干热极端天气对德国冬小麦产量构成最强和最广泛的风险，约占过去产量变化的 38%，在某些地区高达 50%。根据已确定的水文气候易感性区域差异，我们可以定义四个地理风险集群，它们表现出对极端气候的脆弱性，例如夏季干旱、冬季干旱、夏季热浪和冬季水分过剩。 确定的热湿胁迫风险集群可以为区域特定的适应计划提供信息。