In this study, we explore the conditions that led to the unprecedented wildfire that occurred in the Chernobyl Exclusion Zone in April 2020 and the effect of this fire on ¹³⁷Cs dispersal, as wildfires are important drivers of ¹³⁷Cs resuspension, with potentially harmful consequences for the receiving ecosystems. We characterised the historical wildfire record between 2000 and 2020 using the MCD64A1.006 MODIS Burned Area Monthly Global 500 m dataset and assessed the climatic conditions associated with these wildfire events using ERA5-Land reanalysis data. We also examined fire danger indices at the time of these wildfires. We then explored the widespread effects of the April 2020 wildfire on ¹³⁷Cs resuspension and subsequent deposition using the NOAA-HYSPLIT model, concluding that the impacts of such resuspension on areas further afield were minimal. Results show that climatic conditions leading to severe wildfires are increasing, especially during March and April. High soil moisture, relative humidity and extreme temperature anomalies are associated with the largest wildfires on record, and fire risk indices at the time of the April 2020 fire were higher than for other large fires on record. We have estimated that 3854 GBq of ¹³⁷Cs resuspended during the CPPF, with atmospheric transport dominant over Russia, Ukraine, Moldova and Kazakhstan. The observed increase in large wildfires will have implications for wildfire-driven soil erosion processes, which will further exacerbate the effects of atmospheric-driven ¹³⁷Cs redistribution.

在这项研究中，我们探讨了导致 2020 年 4 月切尔诺贝利禁区发生史无前例的野火的条件以及这场火灾对¹³⁷ Cs 扩散的影响，因为野火是¹³⁷ Cs 再悬浮的重要驱动因素，对¹³⁷ Cs 具有潜在的有害后果接收生态系统。我们使用 MCD64A1.006 MODIS Burned Area Monthly Global 500 m 数据集描述了 2000 年至 2020 年间的历史野火记录，并使用 ERA5-Land 再分析数据评估了与这些野火事件相关的气候条件。我们还检查了这些野火发生时的火灾危险指数。然后，我们探讨了 2020 年 4 月野火对¹³⁷使用 NOAA-HYSPLIT 模型进行 Cs 再悬浮和随后的沉积，得出的结论是这种再悬浮对更远地区的影响很小。结果表明，导致严重野火的气候条件正在增加，尤其是在 3 月和 4 月期间。高土壤湿度、相对湿度和极端温度异常与有记录以来最大的野火有关，2020 年 4 月火灾发生时的火灾风险指数高于有记录的其他大型火灾。我们估计 3854 GBq 的¹³⁷Cs 在 CPPF 期间重新悬浮，大气传输在俄罗斯、乌克兰、摩尔多瓦和哈萨克斯坦占主导地位。观察到的大型野火的增加将对野火驱动的土壤侵蚀过程产生影响，这将进一步加剧大气驱动的¹³⁷ Cs 重新分布的影响。