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Abstract. The warmer early Pliocene climate featured changes to global sea surface temperature (SST) patterns, namely a reduction in the Equator–pole gradient and the east–west SST gradient in the tropical Pacific, the so-called “permanent El Niño”. Here we investigate the consequences of the SST changes to silicate weathering and thus to atmospheric CO2 on geological timescales. Different SST patterns than today imply regional modifications of the hydrological cycle that directly affect continental silicate weathering in particular over tropical “hotspots” of weathering, such as the Maritime Continent, thus leading to a “weatherability pattern effect”. We explore the impact of Pliocene-like SST changes on weathering using climate model and silicate weathering model simulations, and we deduce CO2 and temperature at carbon cycle equilibrium between solid Earth degassing and silicate weathering. In general, we find large regional increases and decreases in weathering fluxes, and the net effect depends on the extent to which they cancel. Permanent El Niño conditions lead to a small amplification of warming relative to the present day by 0.4 ∘C, suggesting that the demise of the permanent El Niño could have had a small amplifying effect on cooling from the early Pliocene into the Pleistocene. For the reducedEquator–pole gradient, the weathering increases and decreases largely cancel, leading to no detectable difference in global temperature at carbon cycle equilibrium. A robust SST reconstruction of the Pliocene is needed for a quantitative evaluation of the weatherability pattern effect.
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Data for: The effect of Pliocene regional climate changes on silicate weathering
This dataset stores the data of the article The effect of Pliocene regional climate changes on silicate weathering: a potential amplifier of Pliocene-Pleistocene cooling P. Maffre, J. Chiang & N. Swanson-Hysell, Climate of the Past). This study uses a climate model (GCM) to reproduce an estimate of Pliocene Sea Surface Temperature (SST). The main GCM outputs of this modeling (with a slab ocean model) are stored in "GCM_outputs_for_GEOCLIM/", as well as the climatologies from ERA5 reanalysis. The other GCM outputs that were used in intermediary steps (coupled ocean-atmosphere, and fixed SST simulations) are stored in "other_GCM_outputs/". The forcing files (Q-flux) and other boundary conditions to run the "main" GCM simulations can be found in "other_GCM_outputs/Q-flux_derivation/", as well as the scripts used to generate them. Secondly, the mentioned study uses the GCM outputs in "GCM_outputs_for_GEOCLIM/" as inputs for the silicate weathering model GEOCLIM-DynSoil-Steady-State (https://github.com/piermafrost/GEOCLIM-dynsoil-steady-state/tree/PEN), to investigate weathering and equilibrium CO2 changes due to Pliocene SST conditions. The results of these simulations are stored in "GEOCLIM-DynSoil-Steady-State_outputs/". The purpose of this dataset is to provide the raw outputs used to draw the conclusions of Maffre et al. (2023), and to allow the experiments to be reproduced, by providing the scripts to generate the boundary conditions.
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- Award ID(s):
- 1925990
- PAR ID:
- 10560776
- Publisher / Repository:
- Dryad
- Date Published:
- Subject(s) / Keyword(s):
- FOS: Earth and related environmental sciences FOS: Earth and related environmental sciences
- Format(s):
- Medium: X Size: 35410021289 bytes
- Size(s):
- 35410021289 bytes
- Right(s):
- Creative Commons Zero v1.0 Universal
- Sponsoring Org:
- National Science Foundation
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This dataset contains the output files of numerical simulations of the model GEOCLIM-DynSoil-steady-state, that were conducted for the study "The rise of New Guinea and the fall of Neogene global temperatures". Those outputs are modeled fields of erosion rate, silicate weathering flux, regolith thickness and primary phases depletion, on the island of New Guinea, at 30 minutes resolution, and for 19 time slices from 15 Ma to present-day. This dataset also contains additional Python scripts for generating inputs of the model (namely, slope field) and for projecting the 2D New Guinea erosion field on the 1D transect highlighted in the above-mentioned study. files description The 19 files "gdss_output_NG_slope_X.X-X.X.nc" are output files from the model GEOCLIM-DynSoil-steady-state. "X.X-X.X" indicates the time slice targeted by the simulation (e.g., "14.4-13.2" is "14.4 Ma -- 13.2 Ma). Metadata in each file (netCDF format) describes the fields computed by the model and outputted in the files. Instruction to reproduce those outputs are given in the corresponding branch of the model's Github repository (https://doi.org/10.5281/zenodo.8245945) "Total_erosion.csv" is a 3-column table indicating, for each time interval targeted by the modeling study, the beginning and ending of the time interval, and the total eroded material during that interval, as computed by the model MOVE2D, on the New Guinea 1D transect (see "Transect_locations" files) Because the transect is 1D, the "total eroded material" during a time interval is a 2D value, and its units is km^2. "make_slope_inputs.py" is the Python script that generates the slope field for each time interval, accordingly to the erosion rate during that interval. It uses, as input, a modern (0.5-0Ma) slope field, that can be found in the model's Github repository https://doi.org/10.5281/zenodo.8245945. "erosion_projection.py": script to project the erosion field computed by GEOCLIM-DynSoil-steady-state on the 1D transect, and generate the 2 figures (already present in the current repertory): "erosion_transect_map.png": map the New Guinea erosion with the transect location. "transect_erosion.pdf": plot of the erosion rate along the transect. "geoclim.py": Python script storing the erosion function taken from the GEOCLIM model. This function may be used by "erosion_projection.py", as an alternative way to recompute erosion "from scratch". "Transect_location.*": shapefile indicating the location of 1D New Guinea transect (line).more » « less
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