How Unexpected Was the 2021 Pacific Northwest Heatwave?
How Unexpected Was the 2021 Pacific Northwest Heatwave?
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DOI：
10.1029/2022gl100380
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发表时间：
2022-09-28
影响因子：
5.2
通讯作者：
Simpson, Isla R.
中科院分区：
文献类型：
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作者：
McKinnon, Karen A.;Simpson, Isla R.
2021年太平洋西北部的热浪以破纪录的高温为特征，引发了人们对极端天气变化速度是否快于平均水平的质疑，并挑战了我们估计事件发生概率的能力。在这里，我们识别并利用温度的气候学高阶统计量(偏度和峰度)与极端事件的规模之间的强烈关系，以使用大型气候模型集合(共同体地球系统模型版本2大型集合[CESM2-LE])来量化可比事件的可能性。一般来说，CESM2可以模拟像2021年观测到的那样极端的温度异常，但这种情况很少见：超过4.5西格玛的温度异常发生的频率大约是十万年一次。历史数据没有表明温度的上尾部变暖的速度快于平均值；然而，未来对气候时刻与太平洋西北部相似的地点的预测确实显示出发生最极端事件的概率出现了显著的积极趋势。
The 2021 Pacific Northwest heatwave featured record-smashing high temperatures, raising questions about whether extremes are changing faster than the mean, and challenging our ability to estimate the probability of the event. Here, we identify and draw on the strong relationship between the climatological higher-order statistics of temperature (skewness and kurtosis) and the magnitude of extreme events to quantify the likelihood of comparable events using a large climate model ensemble (Community Earth System Model version 2 Large Ensemble [CESM2-LE]). In general, CESM2 can simulate temperature anomalies as extreme as those observed in 2021, but they are rare: temperature anomalies that exceed 4.5 sigma occur with an approximate frequency of one in a hundred thousand years. The historical data does not indicate that the upper tail of temperature is warming faster than the mean; however, future projections for locations with similar climatological moments to the Pacific Northwest do show significant positive trends in the probability of the most extreme events.