Detecting natural influence on surface air temperature change in the early twentieth century
Detecting natural influence on surface air temperature change in the early twentieth century
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DOI：
10.1029/2005gl023540
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发表时间：
2005-10-29
影响因子：
5.2
通讯作者：
Crooks, SA
中科院分区：
文献类型：
--
作者：
Nozawa, T;Nagashima, T;Crooks, SA
我们分析了由不同外部强迫的耦合气候模式模拟的地表气温数据集，以诊断这些强迫对20世纪初观测到的变暖的相对重要性。在仅受自然因素（火山喷发和太阳变率）影响的模拟中，线性温度趋势的地理分布与观测到的趋势比仅受混合良好的温室气体影响的模拟更吻合。利用最优的指纹技术，我们强有力地发现了20世纪初变暖的重要自然贡献。此外，我们模拟的自然信号的幅值与观测值一致。然而，在同一时期，在存在外部自然强迫的情况下，我们无法在观测到的地表温度中探测到温室气体信号。因此，我们的分析表明，在20世纪初，外部自然因素比人为因素造成的变暖更多。
We analyze surface air temperature datasets simulated by a coupled climate model forced with different external forcings, to diagnose the relative importance of these forcings to the observed warming in the early 20th century. The geographical distribution of linear temperature trends in the simulations forced only by natural contributions (volcanic eruptions and solar variability) shows better agreement with observed trends than that does the simulations forced only by well-mixed greenhouse gases. Using an optimal fingerprinting technique we robustly detect a significant natural contribution to the early 20th century warming. In addition, the amplitude of our simulated natural signal is consistent with the observations. Over the same period, however, we could not detect a greenhouse gas signal in the observed surface temperature in the presence of the external natural forcings. Hence our analysis suggests that external natural factors caused more warming in the early 20th century than anthropogenic factors.