CMIP5 model selection for ISMIP6 ice sheet model forcing: Greenland and Antarctica
CMIP5 model selection for ISMIP6 ice sheet model forcing: Greenland and Antarctica
复制标题
DOI：
10.5194/tc-14-855-2020
复制
发表时间：
2020-03-06
期刊：
影响因子：
5.2
通讯作者：
Bracegirdle, Thomas J.
中科院分区：
文献类型：
--
作者：
Barthel, Alice;Agosta, Cecile;Bracegirdle, Thomas J.
CMIP6的冰盖模型比较项目（ISMIP6）将冰盖和气候建模领域的研究人员汇聚在一起，以了解冰盖对海平面上升的影响。ISMIP6开展独立的冰盖实验，这些实验使用源自大气 - 海洋耦合全球气候模型（AOGCMs）的时空变化强迫，以反映气候预测的合理轨迹。本研究的目标是推荐一组CMIP5的AOGCMs（三个核心模型和三个目标模型），为ISMIP6独立冰盖模拟生成强迫，其依据是：（i）它们相对于观测值对南极洲和格陵兰岛附近当前气候的呈现情况；（ii）它们对21世纪预测的大气和海洋变化多样性进行采样的能力。针对格陵兰岛和南极洲分别进行选择。历史时期的模型评估侧重于用于生成冰盖强迫的变量。对于阶段（i），我们将大气和表层海洋状态的度量指标（大空间区域的年平均和季节平均变量）与大陆架区域平均的时间平均次表层海洋温度偏差度量指标相结合。对于阶段（ii），我们在表现最佳的模型中使气候预测的多样性最大化。模型选择还受到技术限制的约束，例如RCP2.6和RCP8.5预测所需数据的可用性。所选的排名前三的CMIP5气候模型，针对南极洲是CCSM4、MIROC - ESM - CHEM和NorESM1 - M，针对格陵兰岛是HadGEM2 - ES、MIROC5和NorESM1 - M。这种模型选择是专门为ISMIP6设计的，但也可适用于其他应用。
The ice sheet model intercomparison project for CMIP6 (ISMIP6) effort brings together the ice sheet and climate modeling communities to gain understanding of the ice sheet contribution to sea level rise. ISMIP6 conducts stand-alone ice sheet experiments that use space- and time-varying forcing derived from atmosphere-ocean coupled global climate models (AOGCMs) to reflect plausible trajectories for climate projections. The goal of this study is to recommend a subset of CMIP5 AOGCMs (three core and three targeted) to produce forcing for ISMIP6 stand-alone ice sheet simulations, based on (i) their representation of current climate near Antarctica and Greenland relative to observations and (ii) their ability to sample a diversity of projected atmosphere and ocean changes over the 21st century. The selection is performed separately for Greenland and Antarctica. Model evaluation over the historical period focuses on variables used to generate ice sheet forcing. For stage (i), we combine metrics of atmosphere and surface ocean state (annual- and seasonal-mean variables over large spatial domains) with metrics of time-mean subsurface ocean temperature biases averaged over sectors of the continental shelf. For stage (ii), we maximize the diversity of climate projections among the best-performing models. Model selection is also constrained by technical limitations, such as availability of required data from RCP2.6 and RCP8.5 projections. The selected top three CMIP5 climate models are CCSM4, MIROC-ESM-CHEM, and NorESM1-M for Antarctica and HadGEM2-ES, MIROC5, and NorESM1-M for Greenland. This model selection was designed specifically for ISMIP6 but can be adapted for other applications.