Response of convective systems to the orbital forcing of the last interglacial in a global nonhydrostatic atmospheric model with and without a convective parameterization
Response of convective systems to the orbital forcing of the last interglacial in a global nonhydrostatic atmospheric model with and without a convective parameterization
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DOI：
10.1007/s00382-021-06056-5
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发表时间：
2022-01-01
期刊：
影响因子：
4.6
通讯作者：
Satoh, Masaki
中科院分区：
文献类型：
--
作者：
Chikira, Minoru;Yamada, Yohei;Satoh, Masaki
首次将非流体静力二十面体大气模式（NICAM）与平板海洋模式耦合应用于古气候研究。考虑到最后一次间冰期（距今12.7万年）的轨道参数，该模型在56公里的水平分辨率上运行，有和没有对流参数化。在我们的分析中，对对流耦合扰动给予了特别的关注。模拟结果表明，麦登-朱利安振荡信号增强，湿开尔文波减弱。虽然该模式在当前模拟中对北方夏季季内振荡的表现并不令人满意，但在末次间冰期的对应过程中发现其信号显著增强。北太平洋西部、北大西洋热带气旋密度减小，南印度洋和南大西洋热带气旋密度增大。当对流参数化时，模型的性能一般较好，而不进行对流参数化时，模型的性能较好。
Nonhydrostatic Icosahedral Atmospheric Model (NICAM) coupled with a slab ocean model was applied to a paleoclimate research for the first time. The model was run at a horizontal resolution of 56 km with and without a convective parameterization, given the orbital parameters of the last interglacial (127,000 years before present). The simulated climatological mean-states are qualitatively similar to those in previous studies reinforcing their robustness, however, the resolution of this model enables to represent the narrow precipitation band along the southern edge of the Tibetan Plateau. A particular focus was given to convectively coupled disturbances in our analysis. The simulated results show a greater signal of the Madden-Julian Oscillation and weakening of the moist Kelvin waves. Although the model's representation of the boreal summer intraseasonal oscillation in the present-day simulations is not satisfactory, a significant enhancement of its signal is found in the counterpart of the last interglacial. The density of the tropical cyclones decreases over the western north Pacific, north Atlantic and increases over the south Indian Ocean and south Atlantic. The model's performance is generally better when the convective parameterization is used, but the tropical cyclones are better represented without the convective parameterization. Additional simulations using the low-resolution topography reveals that the better representation of the Tibetan Plateau enhances the boreal summer Asian monsoon and its impact is similar and comparable to that of the orbital parameters over the south Asia and the Indian Ocean.