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上新世中期,过去约3.29～2.97Ma之间,是地质历史上距今最近的一个持续性暖期.它与模式预测的21世纪末地球系统最有可能达到的气候态具有一定的可比性.因此,研究该时期气候变化对于理解全球变暖背景下的气候变化趋势具有重要的参考作用.采用最新的PRISM3重建数据集,利用FOAM耦合模式开展了上新世中期的全球气候模拟,并对上新世中期次极地北大西洋剧烈增暖和“永久的ElNio”两个热点问题进行了讨论.模拟结果表明:与工业革命前相比,上新世中期年平均海洋表面温度(SST)升高了2.3℃,中高纬度海洋的增温幅度大于低纬度海洋,赤道太平洋SST东西梯度减小以及大西洋经向翻转环流减弱.在SST变化的空间格局上,模拟结果与重建结果基本一致.FOAM也能较好地模拟出北大西洋、北太平洋以及南美西海岸的显著增暖,但模拟的次极地北大西洋和赤道太平洋SST的变化与重建数据仍有差别.上述重建与模拟的差异是由古气候数据重建的不确定性、上新世中期模拟的困难以及模式本身的不完善共同造成的.
The Middle Pliocene, between 3.29 and 2.97 Ma in the past, is the most recent persistent warm period in geologic history and is comparable to the most probable climatological state predicted by the model in the late 21st century. Therefore, it is important to study the climate change in this period to understand the trend of climate change in the context of global warming.Using the latest PRISM3 reconstruction dataset, the global mid-Pliocene climate simulation was carried out using FOAM coupling model, In the mid-Pliocene, the polar North Atlantic warming and the “permanent El Niño” are discussed. The simulation results show that compared with the pre-industrial revolution, the annual average ocean surface temperature (SST) The temperature increase in the middle and high latitudes was greater than that in the low latitudes, and the gradient of the SST in the equatorial Pacific decreased and the circulation of the Atlantic tumbledown was weakened.With the spatial pattern of the SST changes, the simulation results were basically the same as the reconstruction results. FOAM can also simulate the significant warming of the North Atlantic, the North Pacific and the west coast of South America. However, the simulated SST changes in the northern and eastern equatorial Pacific Built difference data is still above differences and rebuild simulated by the uncertainty of paleoclimate data reconstruction, the mid-Pliocene simulation model as well as difficulties caused by imperfect itself together.