Articles | Volume 10, issue 1
Research article
01 Mar 2016
Research article |  | 01 Mar 2016

The importance of a surface organic layer in simulating permafrost thermal and carbon dynamics

Elchin Jafarov and Kevin Schaefer

Abstract. Permafrost-affected soils contain twice as much carbon as currently exists in the atmosphere. Studies show that warming of the perennially frozen ground could initiate significant release of the frozen soil carbon into the atmosphere. Initializing the frozen permafrost carbon with the observed soil carbon distribution from the Northern Circumpolar Soil Carbon Database reduces the uncertainty associated with the modeling of the permafrost carbon feedback. To improve permafrost thermal and carbon dynamics we implemented a dynamic surface organic layer with vertical carbon redistribution, and introduced dynamic root growth controlled by active layer thickness, which improved soil carbon exchange between frozen and thawed pools. These changes increased the initial amount of simulated frozen carbon from 313 to 560 Gt C, consistent with observed frozen carbon stocks, and increased the spatial correlation of the simulated and observed distribution of frozen carbon from 0.12 to 0.63.

Short summary
To improve the uncertainty in modeling of the permafrost carbon emission associated with the predicted climate warming, it is important to improve the simulation of the current permafrost carbon stock. This work shows how simulation of the frozen carbon in land system models can be improved by better addressing the coupling between plant photosynthesis, soil biogeochemistry, and soil thermodynamics.