Soil Subgrid Heterogeneity Important for Representing High-latitude Processes in a Land Surface Model

Abstract:

Since decades, land surface modeling follows the paradigm of representing ecosystem processes only in the vertical dimension. As a consequence, ecosystem structure is assumed to be mainly controlled by these vertical processes. In particular in permafrost-dominated high-latitude landscapes, several lateral processes such as thermoerosion or cryoturbation equally dominate ecosystem structure and hence ecosystem functions. In order to be able to represent such lateral processes in a land surface model, fine-scale subgrid heterogeneity of soil and vegetation properties need to be represented. Based on data from the Harmonized World Soil Database, several 0.5-degree grids will be setup for the land surface model JSBACH in order to study the effect of subgrid soil properties heterogeneity on the spatial variation of physical state variables such as soil temperature, moisture and ice content. Effects on grid cell-level energy-water-carbon coupling in high latitude ecosystems will be discussed.