Articles | Volume 15, issue 12
© Author(s) 2022. This work is distributed underthe Creative Commons Attribution 4.0 License.
Soil Cycles of Elements simulator for Predicting TERrestrial regulation of greenhouse gases: SCEPTER v0.9
- Final revised paper (published on 29 Jun 2022)
- Preprint (discussion started on 10 Feb 2022)
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
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RC1: 'Comment on gmd-2022-8', Anonymous Referee #1, 10 Mar 2022
- AC1: 'Reply on RC1', Yoshiki Kanzaki, 16 May 2022
RC2: 'Comment on gmd-2022-8', Anonymous Referee #2, 14 Mar 2022
- AC2: 'Reply on RC2', Yoshiki Kanzaki, 16 May 2022
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision
AR by Yoshiki Kanzaki on behalf of the Authors (17 May 2022)  Author's response Author's tracked changes Manuscript
ED: Publish as is (31 May 2022) by Andrea Stenke
The present contribution details a new numerical model designed for simulation of the potential effeciency of the enhanced weathering techniques. Spreading crushed minerals over agricultural fields has been proposed as a technique able to mitigate the atmospheric CO2 rise due to human activities. But the question of the faith of the spread mineral particles has been simulated with very simple methods, and the present contribution aims at improving this description.
The authors describes a mechanistically-based numerical model built to improve the prediction of the amount of CO2 that will be consumed by enhanced weathering. This model is in the ligneage of the CrunchFlow model, which was implemented by Carl Steefle. The new model (Specter) includes a description of the water-mineral interactions based on kinetic laws, the precipitation of secondary phases, the gas diffusion in soils, and the mixing in the upper layer related to the biological activity. All this seems to me correct, and more accurate than parametric methods. I only have a few comments, which can be easily included in a slightly revised version of this ms.
1. Similar models have been implemented since about 30 years. I think that the authors forgot a few references. For examples, ref to the SAFE and PROFILE box-models should appear in the text, because these are the first to apply laboratory kinetic laws to the field. The WITCH model has been also developped to simulate weathering reactions mechanistically, and a version of it includes the CO2 diffusion (check Goddéris et al., 2006, in GCA; Roland et al., 2013 in Biogeosciences; Beaulieu et al. 2012 in Nature Climate Change; Goddéris et al. , 2013 in Biogeosciences). Although not dealing with enhanced weathering, these simpler box-models demonstrate their ability to simulate weathering processes in the field based on a more mechanistic formulation.
2. I found a bit strange to talk about uplift. Is the model really accounting for uplift ? If I understand it correctly, it seems to me that the model is using a referential in which fresh primary minerals are going upwards as weathering proceeds. In the real world, it is the regolith which progressively penetrates the bedrock and thus goes downward. This has nothing to do with uplift ?