This study suggests a methodology for probabilistic forecasts of the extreme heat events in East Asia based on an operational global ensemble prediction used by the Korea Meteorological Administration (KMA). It focuses on the medium range of up to 11 days, providing probabilities of heatwave and tropical night occurrence each day. Forecast validation in the summer from 2016 to 2021 shows that the deterministic heatwave forecast provides 5 days of optimal forecast range, while the probabilistic forecast can extend the practically predictable range up to 10 days in the Korean Peninsula and 7 days in Japan, respectively. Comparing prediction skills for heatwave and tropical night, the skills for tropical night tend to be inferior, presumably due to complex mechanisms of the tropical night and large uncertainty in the numerical model, such as microphysics and radiation. In addition, the coarse resolution of the operational system does not seem to resolve temperature variability at night. As a case study, this study also examines the forecast of the onset and offset of the 2018 South Korean heatwave event. The temporal evolution of the heatwave matches well with the changes in the upper-level atmospheric circulation pattern, which can be used for useful forecast guidance. This probabilistic forecast based on the global ensemble forecasting system is expected to provide reliable prediction information for heatwaves in advance, reducing exposure to extreme events.

中文翻译：

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基于全球集合预报系统的东亚极端高温事件概率中期预报


这项研究提出了一种基于韩国气象局（KMA）使用的全球集合预测的东亚极端高温事件概率预测的方法。它侧重于长达 11 天的中等范围，提供每天热浪和热带夜间发生的概率。 2016年至2021年夏季的预报验证表明，确定性热浪预报提供了5天的最佳预报范围，而概率预报则可以将实际可预报范围分别延长到朝鲜半岛10天和日本7天。比较热浪和热带夜间的预报技术，热带夜间的预报技术往往较差，这可能是由于热带夜间的机制复杂以及数值模型（如微物理和辐射）的不确定性较大。此外，操作系统的粗分辨率似乎并不能解决夜间的温度变化问题。作为案例研究，本研究还研究了 2018 年韩国热浪事件的爆发和抵消的预测。热浪的时间演变与高层大气环流模式的变化吻合良好，可以为预报提供有用的指导。这种基于全球集合预报系统的概率预报有望提前为热浪提供可靠的预报信息，减少极端事件的发生。