Particle filter HadCM3 simulation

Numerical climate output from the HadCM3 climate model simulation runs produced for the ERC funded TITAN project covering the time period 1780-2009 using a particle-filter data-assimilation approach. These data were produced by Andrew Schurer, using the HadCM3 climate model on the EDDIE supercomputer at the University of Edinburgh and the forcings follow the CMIP5 convention. These simulations investigate the role of three modes of climate variability, the North Atlantic Oscillation, El-Niño Southern Oscillation and the Southern Annular Mode, as pacemakers of climate variability since 1781, evaluating where their evolution masks or enhances forced climate trends. We use particle filter data assimilation to constrain the observed variability in a global climate model without nudging, producing a near free running model simulation with the time-evolution of these modes similar to those observed. Since the climate model also contains external forcings, these simulations, in combination with model experiments with identical forcing but no assimilation, can be used to compare the forced response to the effect of the three modes assimilated, and evaluate to what extent these are confounded with the forced response. A description of this dataset can be found in: Schurer, A.P., Hegerl, G.C., Goosse, Bollasina, M.A., England, M.H., Mineter, M.J., Smith, D.M., and Tett, S.F.B. (2022). Quantifying the contribution of forcing and three prominent modes of variability on historical climate. Climate of the Past Discussions, 1-25 - doi.org/10.5194/cp-2022-55.

本数据集为欧洲研究理事会（European Research Council, ERC）资助的TITAN项目所开展的HadCM3气候模型（HadCM3 climate model）模拟试验的数值气候输出结果，模拟时段覆盖1780年至2009年，采用粒子滤波数据同化（particle-filter data-assimilation）方法生成。该数据集由Andrew Schurer基于爱丁堡大学EDDIE超级计算机上的HadCM3气候模型运行生成，所用外强迫场遵循CMIP5（Coupled Model Intercomparison Project Phase 5）规范。本模拟试验旨在探究1781年以来三种气候变率模态——北大西洋涛动（North Atlantic Oscillation, NAO）、厄尔尼诺-南方涛动（El-Niño Southern Oscillation, ENSO）与南方环状模（Southern Annular Mode, SAM）——作为气候变率起搏因子的作用，并评估其演变如何掩盖或增强受迫气候趋势。本研究采用粒子滤波数据同化方法，在不施加松弛同化（nudging）的前提下约束全球气候模型中的观测变率，得到与观测到的三种模态时间演变特征高度相似的准自由运行模型模拟结果。由于该气候模型同时包含外强迫信号，本模拟试验可与强迫场一致但未进行数据同化的模型试验相结合，用于对比受迫气候响应与同化的三种变率模态的影响，并评估二者的混淆程度。本数据集的详细说明可参见：Schurer, A.P.、Hegerl, G.C.、Goosse、Bollasina, M.A.、England, M.H.、Mineter, M.J.、Smith, D.M.、Tett, S.F.B.（2022）。《量化强迫与三种主要变率模态对历史气候的贡献》，《古气候讨论》（Climate of the Past Discussions），1-25页，doi.org/10.5194/cp-2022-55。