Tightly linked zonal and meridional sea surface temperature gradients over the past five million years

Climatologies for the climate model simulations performed by Fedorov et al., Nature Geoscience, https://www.nature.com/articles/ngeo2577. This table shows how the names of the simulation files provided in this dataset relate to the experiment names provided in Table S2 of Fedorov et al., (2015, Nature Geoscience). Note that experiments 1-26 are from Burls and Fedorov (2014) and published in https://doi.org/10.5281/zenodo.6762450

Experiment # in Article (Table S2)
Name of Files

27

abrupt2xCO2_T31_gx3v7*.nc

28

abrupt4xCO2_T31_gx3v7*.nc

29

abrupt8xCO2_T31_gx3v7*.nc

30

abrupt16xCO2_T31_gx3v7*.nc

Extended Exp 11
40p_ILWP_1590deg_tropx2_T31_gx3v7*.nc

Extended Exp 16
60p_ILWP_1590deg_tropx4_T31_gx3v7*.nc

Article abstract:

The climate of the tropics and surrounding regions is defined by pronounced zonal (east–west) and meridional (equator to mid-latitudes) gradients in sea surface temperature. These gradients control zonal and meridional atmospheric circulations, and thus the Earth’s climate. Global cooling over the past five million years, since the early Pliocene epoch, was accompanied by the gradual strengthening of these temperature gradients. Here we use records from the Atlantic and Pacific oceans, including a new alkenone palaeotemperature record from the South Pacific, to reconstruct changes in zonal and meridional sea surface temperature gradients since the Pliocene, and assess their connection using a comprehensive climate model. We find that the reconstructed zonal and meridional temperature gradients vary coherently over this time frame, showing a one-to-one relationship between their changes. In our model simulations, we systematically reduce the meridional sea surface temperature gradient by modifying the latitudinal distribution of cloud albedo or atmospheric CO2 concentration. The simulated zonal temperature gradient in the equatorial Pacific adjusts proportionally. These experiments and idealized modelling indicate that the meridional temperature gradient controls upper-ocean stratification in the tropics, which in turn controls the zonal gradient along the equator, as well as heat export from the tropical oceans. We conclude that this tight linkage between the two sea surface temperature gradients posits a fundamental constraint on both past and future climates.