Global reanalyzes are widely used for investigations of Antarctic climate variability and change. The European Centre for Medium-Range Weather Forecasts 5th generation reanalysis (ERA5) is well regarded and spans 1940 to today. We investigate whether ERA5 reliably represents the 2-m air temperature trends across the 1940–2022 (83 years) period at seasonal and annual time scales. We compare ERA5 temperatures with an observation-based temperature reconstruction for Antarctica (RECON) that has monthly resolution for 1958–2022, the period of reliable observational availability. Results for individual stations are also examined. ERA5 anomalously warms Antarctica in relation RECON especially for the period prior to 1979 when satellite observations over the Southern Ocean were sparse. Trend hotspots that are shown to be artifacts are found at three locations and are present until today. The results demonstrate that ERA5 temperature trends can be questionable even today, but variability is well captured after 1979.

中文翻译：

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ERA5 中的主要伪影 现代卫星时代之前和期间南极洲 2 米气温趋势


全球再分析广泛用于南极气候变率和变化的研究。欧洲中期天气预报中心第 5 代再分析 （ERA5） 广受好评，时间跨度从 1940 年至今。我们研究了 ERA5 是否可靠地代表了 1940-2022 年（83 年）期间在季节和年度时间尺度上的 2 m 气温趋势。我们将 ERA5 温度与基于观测的南极洲温度重建 （RECON） 进行了比较，后者在 1958-2022 年（可靠观测可用性的时期）具有月度分辨率。此外，还会检查各个站点的结果。ERA5 与 RECON 相关异常地使南极洲变暖，尤其是在 1979 年之前，当时南大洋的卫星观测很少。在三个位置发现了显示为伪影的趋势热点，并且一直存在到今天。结果表明，即使在今天，ERA5 温度趋势也可能值得怀疑，但在 1979 年之后可以很好地捕捉到可变性。