Wintertime warm extremes in the high Arctic, primarily associated with intrusions of moist airmasses from the midlatitudes, have occurred with an ostensibly high frequency in recent years. Here, we compute the temperature anomaly return values associated with such events for long return times. Our approach, which we term space‐time maxima–exposure (STM–E), improves on conventional extreme value estimates performed on a single‐location basis by explicitly taking into account the spatial structure of the moisture intrusions driving the temperature extremes. We specifically show that the STM–E approach provides spatially smoother return value estimates, a lower uncertainty in the parameters of the extreme value distribution fits and mitigates the single‐location underestimation of the magnitude of return values of temperature extremes.

中文翻译：

---

高北极地区温暖极端返回值的空间模型

近年来，北极高海拔地区冬季的温暖极端现象的发生频率很高，这主要与中纬度地区的潮湿气团侵入有关。在这里，我们计算与此类事件相关的温度异常返回值的返回时间较长。我们的方法被称为时空最大暴露（STM-E），它通过明确考虑驱动极端温度的水分入侵的空间结构，改进了在单个位置进行的常规极值估计。我们具体表明，STM-E方法提供了空间上更平滑的返回值估计，极值分布的参数的不确定性较低，并且减轻了温度极值返回值幅度的单位置低估。