Climate and stratospheric ozone during the mid-Holocene and Last Interglacial simulated by MRI-ESM2.0

Abstract. The climates of the mid-Holocene (MH) and Last Interglacial (LIG) are characterised by warm periods caused by astronomical forcing and climate feedback. One potential feedback is variation in the stratospheric ozone, the influence of which would extend down to the troposphere, potentially affecting the climate. However, understanding the role of changes in the stratospheric ozone during past warm interglacial periods is limited to MH conditions. Here, we employ MRI-ESM2.0, an Earth system model with an iterative ozone model, and simulate the climate and atmospheric ozone during the MH and LIG. We show that the vertical and seasonal changes of stratospheric ozone in the LIG exhibited a stronger variation in the stratospheric ozone near the South Pole compared to that in the MH, indicating that both obliquity and precession forcings affect the stratospheric ozone distributions. We further show that its impact on the zonal mean surface air temperature is small, while it may affect surface air temperature regionally. These results advance the understanding of the dynamics of atmospheric ozone to astronomical forcing during the warm interglacials.