Permafrost sub-grid heterogeneity of soil properties key for 3-D soil processes and future climate projections

• Published in: Frontiers in Earth Science
• Main Author: Christian Beer
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2016
• Subjects: Carbon Cycle; Permafrost; soil heterogeneity; soil temperature; Cryoturbation; Climate projection; Science; Q; Arctic; Active layer thickness; permafrost; Siberia
• Online Access: https://doi.org/10.3389/feart.2016.00081; https://doaj.org/article/e431b4efc0054f77b9a975a5b61ff6b3

There are massive carbon stocks stored in permafrost-affected soils due to the 3-D soil movement process called cryoturbation. For a reliable projection of the past, recent and future Arctic carbon balance, and hence climate, a reliable concept for representing cryoturbation in a land surface model (LSM) is required. The basis of the underlying transport processes is pedon-scale heterogeneity of soil hydrological and thermal properties as well as insulating layers, such as snow and vegetation. Today we still lack a concept of how to reliably represent pedon-scale properties and processes in a LSM. One possibility could be a statistical approach. This perspective paper demonstrates the importance of sub-grid heterogeneity in permafrost soils as a pre-requisite to implement any lateral transport parametrization. Representing such heterogeneity at the sub-pixel size of a LSM is the next logical step of model advancements. As a result of a theoretical experiment, heterogeneity of thermal and hydrological soil properties alone lead to a remarkable initial sub-grid range of subsoil temperature of 2 deg C, and active-layer thickness of 150 cm in East Siberia. These results show the way forward in representing combined lateral and vertical transport of water and soil in LSMs.