Long term climate data are key in assessing water related hazards in order to adapt and mitigate climate change. Reanalysis has been developed as a surrogate for local observations, but there is a lack of studies about the suitability at different parts of the world. In this study, our primary goal of this study was to identify the applicability of the ECMWF 20th century atmospheric model ensemble (ERA-20cm) in South Korea. Thus, we have evaluated the ensemble for precipitation and temperature by assessing the correlation coefficients, the long-term trend by the Mann-Kendall test, the skill score based on the probability density functions (PDFs) and the goodness of the ensemble spread. The relationship between the spread and the El Niño-Southern Oscillation (ENSO) has also been explored. ERA-20cm ensemble has difficulty in providing useful information on the long term trend as well as the temporal variability in South Korea, but, for the pdf-based comparison, all ensemble predictions represent significant agreements. It is found that the ensemble mean can misrepresent ten individual members, especially for statistical estimates, in regional-scale analyses. The ensemble does not spread well enough to cover the observation and there is no relationship between the spread and ENSO. This paper shows that the applicability of ERA-20cm may vary by region, hence these findings help to fill in the knowledge gaps about the applicability of the reanalysis in regional scale study including South Korea.

长期气候数据对于评估与水有关的危害以适应和缓解气候变化至关重要。重新分析已被开发出来作为当地观测的替代品，但是缺乏关于世界不同地区的适用性的研究。在这项研究中，我们的主要目标是确定ECMWF 20世纪大气模型集合（ERA-20cm）在韩国的适用性。因此，我们通过评估相关系数，Mann-Kendall检验的长期趋势，基于概率密度函数（PDF）的技能得分以及整体传播的优劣来评估降水和温度的整体。还研究了传播与厄尔尼诺-南方涛动（ENSO）之间的关系。ERA-20cm合奏很难提供有关韩国长期趋势以及时间变异性的有用信息，但是对于基于pdf的比较，所有合奏的预测都代表了重要的共识。结果发现，在区域规模分析中，总体平均值可能会误代表十个成员，尤其是对于统计估计而言。该集合的传播范围不足以覆盖观测值，并且传播与ENSO之间没有关系。本文表明，ERA-20cm的适用性可能因地区而异，因此，这些发现有助于弥补在包括韩国在内的区域规模研究中有关再分析适用性的知识空白。所有整体预测都代表重要的共识。发现在区域规模分析中，总体平均值可能会错误地代表十个人，特别是对于统计估计而言。该集合的传播范围不足以覆盖观测值，并且传播与ENSO之间没有关系。本文表明ERA-20cm的适用性可能因地区而异，因此，这些发现有助于填补包括韩国在内的区域规模研究中有关再分析的适用性的知识空白。所有整体预测都代表重要的共识。发现在区域规模分析中，总体平均值可能会错误地代表十个人，特别是对于统计估计而言。该集合的传播范围不足以覆盖观测值，并且传播与ENSO之间没有关系。本文表明ERA-20cm的适用性可能因地区而异，因此，这些发现有助于填补包括韩国在内的区域规模研究中有关再分析的适用性的知识空白。