Preprints
https://doi.org/10.5194/egusphere-2022-151
https://doi.org/10.5194/egusphere-2022-151
 
26 Apr 2022
26 Apr 2022

The modelled climatic response to the 18.6-year lunar nodal cycle and its role in decadal temperature trends

Manoj Joshi1,2, Robert Hall1, David Stevens3, and Ed Hawkins4 Manoj Joshi et al.
  • 1School of Environmental Sciences, University of East Anglia, Norwich NR4 7SQ, United Kingdom
  • 2Climatic Research Unit, University of East Anglia, Norwich NR4 7SQ, United Kingdom
  • 3School of Mathematics, University of East Anglia, Norwich NR4 7SQ, United Kingdom
  • 4National Centre for Atmospheric Science, Department of Meteorology, University of Reading, Reading RG6 6BB, United Kingdom

Abstract. The 18.6-year lunar nodal cycle arises from variations in the angle of the Moon’s orbital plane. Previous work has linked the nodal cycle to climate but has been limited, either by the length of observations analysed, or geographical regions considered in model simulations of the pre-industrial period. Here we examine the global effect of the lunar nodal cycle in multi-centennial climate model simulations of the pre-industrial period. We find cyclic signals in global and regional surface air temperature having amplitudes of O (0.1 K), ocean heat uptake and ocean heat content. The timing of anomalies of global surface air temperature and heat uptake are consistent with the so-called slowdown in global warming in the first decade of the 21st century, also displaying warmer than average Arctic surface temperatures at the same time. The lunar nodal cycle causes variations in mean sea level pressure exceeding 0.5 hPa in the Nordic seas region, thus affecting the North Atlantic Oscillation Index during boreal winter. Our results suggest that the contribution of the lunar nodal cycle to global temperature should be negative in the mid-2020s before becoming positive again in the early-2030s, reducing the uncertainty in time at which projected global temperature reaches 1.5 C above pre-industrial levels.

Manoj Joshi et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • AC1: 'Comment on egusphere-2022-151', Manoj Joshi, 03 May 2022
  • CC1: 'Comment on egusphere-2022-151', Michael Wallace, 05 May 2022
  • CC2: 'Comment on egusphere-2022-151', Paul PUKITE, 12 May 2022
  • RC1: 'Comment on egusphere-2022-151', Anonymous Referee #1, 20 May 2022
    • CC3: 'Reply on RC1', Paul PUKITE, 23 May 2022
  • CC4: 'Comment on egusphere-2022-151', Mikh Kova, 05 Jul 2022
    • EC1: 'Reply on CC4', Axel Kleidon, 26 Aug 2022
  • CC5: 'Comment on egusphere-2022-151', Adam Blaker, 18 Aug 2022
    • RC3: 'Reply on CC5', Adam Blaker, 23 Aug 2022
  • RC2: 'Comment on egusphere-2022-151', Adam Blaker, 23 Aug 2022
  • RC4: 'Comment on egusphere-2022-151', Anonymous Referee #3, 24 Aug 2022

Manoj Joshi et al.

Data sets

Lunar nodal cycle forcing data M. Joshi, R. Hall, D. Stevens, E. Hawkins https://research-portal.uea.ac.uk/en/datasets/lunar-nodal-cycle-amplitude-modulation-map

Manoj Joshi et al.

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Short summary
The 18.6-year lunar nodal cycle arises from variations in the angle of the Moon’s orbital plane and affects ocean tides. In this work we use a climate model to examine the effect of this cycle on the ocean, surface and atmosphere. The timing of anomalies is consistent with the so-called slowdown in global warming, and have implications for when global temperatures will exceed 1.5 C above pre-industrial levels. Regional anomalies have implications for seasonal climate over Europe especially.