标题： ERA5地表温度时间序列中的变化点检测 显示英文标题

标题： Change point detection in ERA5 ground temperature time series

摘要： 我们分析了ERA5再分析数据中所有陆地网格点的2米温度时间序列，使用变化点分析。我们将两个线性斜率拟合到数据上，约束它们在斜率变化的时间点合并。我们通过两种方式将这些拟合与标准线性回归进行比较：我们使用Akaike信息准则和贝叶斯信息准则进行模型选择，并对无趋势值变化的原假设进行检验。对于双线性拟合更优的网格点，我们构建了趋势变化的时间图以及两个时间段内的变暖趋势图。在此过程中，我们识别出变暖加速的区域，同时也发现了一些变暖减缓的区域。我们因此对气候变化局部效应的描述做出了贡献。我们发现许多网格点在1980年代左右表现出更强的变暖趋势。这引发了关于气候系统是否已经通过某些临界点的问题。 显示英文摘要

摘要： We analyze the ERA5 reanalysis 2-meter temperature time series on all land grid points using change point analysis. We fit two linear slopes to the data with the constraint that they merge at the point in time where the slope changes. We compare such fits to a standard linear regression in two ways: We use Akaike's and the Bayesian information criteria for model selection, and we test against the null hypothesis of no change of the trend value. For those grid points where the dual linear fit is superior, we construct maps of the time when the trend changes, and of the warming trends in both time intervals. In doing so, we indentify areas where warming speeds up, but find as well areas where warming slows down. We thereby contribute to the characterization of local effects of climate change. We find that many grid points exhibit a change to a much stronger warming trend around the 1980s. This raises the question of whether the climate system has already passed some tipping point.