Earth Science Frontiers ›› 2024, Vol. 31 ›› Issue (1): 486-499.DOI: 10.13745/j.esf.sf.2024.1.5

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Transient and time-slice simulations of global climate change during the Last Interglacial: Model-model and model-data comparisons

JIANG Nanxuan1,2(), YAN Qing1,3, WANG Huijun1,3,*()   

  1. 1. Nansen-Zhu International Research Centre, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
    3. Key Laboratory of Meteorological Disaster, Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China
  • Received:2023-11-02 Revised:2023-12-28 Online:2024-01-25 Published:2024-01-25

Abstract:

Performing transient simulation during 129-124 ka (TGCS-LIG) at high temporal and spatial resolutions (~1° × 1°, without orbital acceleration) and time-slice experiment at 127 ka (127ka-LIG) can advance our knowledge on the role of experimental setup in the simulation of climate change during the Last Interglacial (LIG). Here, we quantitatively estimate the impact of the experimental setup on the simulated global climate change during the LIG, which may shed light on the potential reasons for model-data discrepancies during the LIG. According to TGCS-LIG/127ka-LIG experiments, the global annual mean surface temperatures decreased by 0.4 ℃/0.2 ℃ during LIG relative to the preindustrial era, with the summer surface temperature over the Northern (Southern) Hemisphere increased (decreased) by 1.2 ℃/1.5 ℃ (0.9 ℃/0.7 ℃). During LIG, the annual mean monsoonal precipitation increased (decreased) over the Northern (Southern) Hemisphere, with large discrepancies across sub-regions. The hit rates (i.e., percentage agreement between model and reconstructed data) and root mean square errors were comparable between the two experiments. For global annual (summer) sea surface temperatures, the hit rates between TGCS-LIG and reconstructions were 34.9%-44.7% (36.8%-42.5%), biased by ~2%-4% (~5%-7%) compared with that of 127ka-LIG; root mean square errors between TGCS-LIG and reconstructions were 2.9-3.2 ℃ (2.9-3.4 ℃), which were ~0.1 ℃ biased compared with 127ka-LIG (generally consistent with 127ka-LIG). For global annual precipitation, the hit rate between TGCS-LIG and multi-proxies was 63.8%, higher by 0.7% relative to 127ka-LIG. The above results indicated that model-model differences were relatively small compared with model-data discrepancies. It is worth noting that TGCS-LIG suggested that the interannual variability of the ENSO showed an increasing trend, whereas the interannual variability of the Northern Hemisphere Annular Mode and Southern Hemisphere Annular Mode fluctuated. These characteristics of varied interannual variability revealed by TGCS-LIG were hardly deciphered in 127ka-LIG. Overall, we suggest that the differences in experimental setup for LIG climate simulations ((i.e. using the time-slice experiment or the transient simulation) may have limited impact on reconciling model-data discrepancies during the LIG, nevertheless, we still highlight the importance of performing transient simulation at high resolution in the investigation of climate variability during the LIG.

Key words: Last Interglacial, model-data comparisons, transient simulation, time-slice experiment

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