Larger Sensitivity of Precipitation Extremes to Aerosol Than Greenhouse Gas Forcing in CMIP5 Models
Larger Sensitivity of Precipitation Extremes to Aerosol Than Greenhouse Gas Forcing in CMIP5 Models
复制标题
CMIP5 模型中极端降水对气溶胶的响应比温室气体强迫的敏感性更大
DOI：
10.1029/2018jd028821
复制
发表时间：
2018-08-16
影响因子：
4.4
通讯作者：
Dong, Wenjie
中科院分区：
文献类型：
--
作者：
Lin, Lei;Wang, Zhili;Dong, Wenjie
使用耦合模型比较计划第 5 阶段 (CMIP5) 的二十世纪历史多模式集合模拟来检查极端降水量（PE；即全球平均表面温度每变化一度 PE 的变化）对气溶胶和温室气体 (GHG) 强迫的敏感性。我们发现，在所有可用模型中，PE 对气溶胶的敏感性远高于 GHG。多模式集合中全球平均月最大连续 5 天降水量 (RX5day) 和最大 1 天降水量 (RX1day) 的气溶胶/温室气体引起的敏感度比分别为 1.6 和 1.4。在陆地上，RX5day 和 RX1day 的相应比率分别为 2.3 和 1.8。特别是，在西非、中国东部、南亚和东南亚、南美洲西北部和东欧，气溶胶强迫的敏感性比温室气体强迫高几倍。大气能量平衡、动力调节和强迫的垂直结构都导致PE对两种强迫的敏感度存在差异。结果表明，对于平均降水量而言，快速响应主要导致 PE 敏感性的气溶胶与温室气体比率大于 1。这是因为温室气体大气强迫引起了更强的降水抑制作用。我们还发现，PE 敏感性的气溶胶与温室气体之比取决于定义的极端降水指数。对于更宽松定义的 PE，气溶胶与温室气体的敏感性比更大，对于更严格定义的 PE，它逐渐收敛到 1。我们的结果进一步强调了在预测 PE 变化时考虑人为气溶胶减少的重要性。
The sensitivity of precipitation extremes (PEs; i.e., the change in PE per degree of change in global mean surface temperature) to aerosol and greenhouse gas (GHG) forcings is examined using the twentieth century historical multimodel ensemble simulations from the Coupled Model Intercomparison Program phase 5 (CMIP5). We find a robustly larger sensitivity of PE to aerosols than GHGs across all available models. The aerosol/GHG‐induced sensitivity ratios for globe‐averaged monthly maximum consecutive 5‐day precipitation (RX5day) and maximum 1‐day precipitation (RX1day) in the multimodel ensemble are 1.6 and 1.4, respectively. Over land, the corresponding ratios for RX5day and RX1day are 2.3 and 1.8, respectively. In particular, the aerosol forcing leads to several times greater sensitivity than GHG forcing in West Africa, eastern China, South and Southeast Asia, northwestern South America, and Eastern Europe. The atmospheric energy balance, dynamical adjustment, and vertical structure of forcing, all contribute to the difference in the PE sensitivity to the two forcings. It is shown that the fast response primarily contributes to the greater‐than‐one aerosol‐to‐GHG ratios of the PE sensitivities, as for the mean precipitation. This is because of a stronger rainfall suppression effect induced by the GHG atmospheric forcing. We also find that the aerosol‐to‐GHG ratios of the PE sensitivities depend on the defined extreme precipitation indices. The aerosol‐to‐GHG sensitivity ratio is larger for more loosely defined PE, and it gradually converges to one for more severely defined PE. Our results further highlight the importance of considering the anthropogenic aerosol reduction in projecting the change in PE.