EGU21-9158
https://doi.org/10.5194/egusphere-egu21-9158
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Calibrating SoilGen2 for interglacial soil evolution in the Chinese Loess Plateau considering soil parameters, and the effect of uncertain forcings’

Keerthika Nirmani Ranathunga1,2, Peter Finke1, Qiuzhen Yin2, and Yanyan Yu3
Keerthika Nirmani Ranathunga et al.
  • 1Department of Environment, Research group of soilscape genesis, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
  • 2Earth and Life Institute, Georges Lemaitre Center for Earth and Climate Research, Université Catholique de Louvain, Place Louis Pasteur 3, B-1348 Louvain-la-Neuve, Belgium
  • 3Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS), 19, Beitucheng Xilu, Chaoyang District, 100029, Beijing, China

To better understand interglacial paleosol formation by quantifying the paleosol formation processes on the Chinese Loess Plateau (CLP), we need a soil genesis model calibrated for long timescales.  Here, we calibrate a process-based soil genesis model, SoilGen2, by confronting simulated and measured soil properties for interglacial soils formed in the CLP for various parameter settings. After the calibration of the intrinsic soil process parameters, the effect of uncertainty of external forcings (e.g. dust deposition) on calibration results was assessed.

This calibration comprises three major soil process formulations, represented by various process parameters. Sequentially : [1]. decalcification by tuning (i) the dissolution constant of calcite (ii) the interception evaporation fraction [2]. clay migration by tuning (iii) the volume of clay in-contact with macropores (iv) the filter coefficient (v) physical weathering (vi) the ectorganic layer thickness [3]. soil organic carbon by tuning the decay rates of (vii) humus and (viii) resistant plant material, and (ix) the ratio of ectorganic/endorganic litter (natural vegetations) (x) the ratio of carbon mineralized (CO2) over that still in the food web (biomass and humus) during decomposition. The order of the tuned parameters was based on sensitivity analyses on parameters for modelling (de-)calcification and clay migration done for West European leaching climates, and on C-cycling parameters done for both West European and Chinese circumstances. These parameters, [1 and 3] and [2] were successfully calibrated to the Holocene and the Marine Isotope Stage (MIS) 13 climate evolution of the CLP, respectively. After calibration, soil properties show a strong response to 10 reconstructed dust deposition scenarios reflecting the propagation of uncertainty in dust deposition.

Our results emphasize the equal importance of calibrating soil process parameters and defining correct external forcings in the future use of soil models. Nevertheless, this calibrated model permits interglacial soil simulation in the CLP over long timescales.

How to cite: Ranathunga, K. N., Finke, P., Yin, Q., and Yu, Y.: Calibrating SoilGen2 for interglacial soil evolution in the Chinese Loess Plateau considering soil parameters, and the effect of uncertain forcings’, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9158, https://doi.org/10.5194/egusphere-egu21-9158, 2021.

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