Ecotron facilities allow accurate control of many environmental variables coupled with extensive monitoring of ecosystem processes. They therefore require multivariate perturbation of climate variables, close to what is observed in the field and projections for the future. Here, we present a new method for creating realistic climate forcing for manipulation experiments and apply it to the UHasselt Ecotron experiment. The new methodology uses data derived from the best available regional climate model projection and consists of generating climate forcing along a gradient representative of increasingly high global mean air temperature anomalies. We first identified the best-performing regional climate model simulation for the ecotron site from the Coordinated Regional Downscaling Experiment in the European domain (EURO-CORDEX) ensemble based on two criteria: (i) highest skill compared to observations from a nearby weather station and (ii) representativeness of the multi-model mean in future projections. The time window is subsequently selected from the model projection for each ecotron unit based on the global mean air temperature of the driving global climate model. The ecotron units are forced with 3-hourly output from the projections of the 5-year period in which the global mean air temperature crosses the predefined values. With the new approach, Ecotron facilities become able to assess ecosystem responses on changing climatic conditions, while accounting for the co-variation between climatic variables and their projection in variability, well representing possible compound events. The presented methodology can also be applied to other manipulation experiments, aiming at investigating ecosystem responses to realistic future climate change.

中文翻译：

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一种在 Ecotron 实验中评估气候变化影响的新方法

Ecotron 设施可以准确控制许多环境变量，同时对生态系统过程进行广泛监测。因此，它们需要对气候变量进行多变量扰动，接近现场观察到的情况和对未来的预测。在这里，我们提出了一种为操作实验创建逼真气候强迫的新方法，并将其应用于 UHasselt Ecotron 实验。新方法使用来自最佳可用区域气候模型预测的数据，包括沿代表越来越高的全球平均气温异常的梯度产生气候强迫。我们首先根据两个标准从欧洲域协调区域降尺度实验 (EURO-CORDEX) 集合中确定了 Ecotron 站点的最佳区域气候模型模拟：(i) 与附近气象站的观测相比的最高技能和(ii) 多模型平均值在未来预测中的代表性。随后根据驱动全球气候模型的全球平均气温，从每个ecotron 单元的模型投影中选择时间窗口。根据全球平均气温超过预定义值的 5 年期间的预测，ecotron 装置被迫每 3 小时输出一次。通过新方法，Ecotron 设施能够评估生态系统对不断变化的气候条件的反应，同时考虑到气候变量之间的协变及其变化预测，很好地代表了可能的复合事件。所提出的方法也可以应用于其他操纵实验，旨在研究生态系统对现实未来气候变化的反应。