Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
doi:10.5194/bg-2016-549
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
12 Jan 2017
Review status
This discussion paper has been under review for the journal Biogeosciences (BG). The manuscript was not accepted for further review after discussion.
Improvement of Soil Respiration Parameterization in a Dynamic Global Vegetation Model and Its Impact on the Simulation of Terrestrial Carbon Fluxes
Dongmin Kim, Myong-In Lee, and Eunkyo Seo School of Urban and Environmental Engineering, UNIST, Ulsan, Korea
Abstract. Soil decomposition is one of the critical processes for maintaining a terrestrial ecosystem and the global carbon cycle. The sensitivity of soil respiration (Rs) to temperature, the so-called Q10 value, is required for parameterizing the soil decomposition process and is assumed to be a constant in conventional numerical models, while realistically it is not in cases of spatiotemporal heterogeneity. This study develops a new parameterization method for determining Q10 by considering the soil respiration dependence on soil temperature and moisture obtained by multiple regression. This study further investigates the impacts of the new parameterization on the global terrestrial carbon flux. Our results show that non-uniform spatial distribution of Q10 tends to represent the dependence of the soil respiration process on heterogeneous surface vegetation type compared with the control simulation using a uniform Q10. Moreover, it tends to improve the simulation of the observed relationship between soil respiration and soil temperature and moisture, particularly over cold and dry regions. The new parameterization improves the simulation of gross primary production (GPP). It leads to a more realistic spatial distribution of GPP, particularly over high latitudes (60–80 N) where the original model has a significant underestimation bias. In addition, overestimation bias of GPP in the tropics and the midlatitudes is significantly reduced. Improvement in the spatial distribution of GPP leads to a substantial reduction of global mean bias of GPP from +9.11 to +1.68 GtC yr−1 compared with the FLUXNET-MTE observation data.

Citation: Kim, D., Lee, M.-I., and Seo, E.: Improvement of Soil Respiration Parameterization in a Dynamic Global Vegetation Model and Its Impact on the Simulation of Terrestrial Carbon Fluxes, Biogeosciences Discuss., doi:10.5194/bg-2016-549, 2017.
Dongmin Kim et al.
Dongmin Kim et al.

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Short summary
This study investigates the impacts of temperature sensitivity of soil respiration (Q10) on the terrestrial carbon cycle using CLM4 off-line simulation. This study develops a new parameterization for determining Q10 by considering the soil respiration dependence on soil temperature and moisture obtained by multiple regression. The results show that distribution of heterogenous Q10 induces to overcome the soil respiration and GPP distribution comparing with original Q10 parameterization.
This study investigates the impacts of temperature sensitivity of soil respiration (Q10) on the...
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