JSBACH

JSBACH is the land component of the MPI Earth System Models MPI-ESM and ICON-ESM. As integral part of the respective atmospheric component (ECHAM, ICON-A), it provides the lower atmospheric boundary conditions over land. In addition, it adds the biogeochemical and biogeophysical degrees of freedom to the Earth system dynamics that arise from terrestrial processes.

JSBACH has originally been derived by isolating the land components from ECHAM5 (Roeckner et al., 2003), in particular the soil hydrology, the soil heat transport, and the land surface energy balance. To represent the dynamics of land carbon uptake and release, the core system has subsequently been extended by incorporating the photosynthesis and canopy radiation components from the BETHY model (Knorr, 1998), by adding a prognostic phenology scheme, and by developing suitable components for uptake, storage, and release of carbon from vegetation and soils. Natural changes in the geographic extent of landcover is simulated prognostically by a dynamic vegetation module (including wind and fire damage) whereas anthropogenic land cover change is prescribed either by sequences of maps, or by forcing JSBACH with the transition matrices of the Opens external link in current windowNew Hampshire Harmonized Protocol.

The most recent version JSBACH 4 is part of ICON-ESM. This is a major re-write of the standard land component JSBACH 3 of MPI-ESM. Development of this latter version has stopped, but its maintenance will be continued until it is superseded by JSBACH 4.  

Accessing the JSBACH source code 

Publications with JSBACH

Configurations

JSBACH can be run online, i.e. as part of its atmospheric host model ECHAM6 or ICON-A, or offline ("JSBALONE") forced by climate data. The resolution of the online version is determined by the hosting model, whereas the resolution of the offline version follows the resolution of the climate forcing data. In a third configuration ("CBALONE"), the land biochemical cycles (carbon, nitrogen) as well as the sub-models for land cover change can be run separately such that, when forced by simulation data from online runs, land cover and biochemical tracers can be reproduced to numerical accuracy.

Documentation

A full documentation is under development. Particular aspects of the model are described in:

Land physics and coupling to atmosphere: Roeckner, E., G. Bäuml, L. Bonaventura, R. Brokopf, M. Esch, M. Giorgetta, S. Hagemann, I. Kirchner, L. Kornblueh, E. Manzini, A. Rhodin, U. Schlese, U. Schulzweida, A. Tompkins: The atmospheric general circulation model ECHAM 5. PART I: Model description, MPI Report 349 (2003)

Land biochemical cycles: Goll, D., Winkler, A., Raddatz, T., Dong, N., Prentice, I., Ciais, P. & Brovkin, V. (2017). Carbon-nitrogen interactions in idealized simulations with JSBACH (version 3.10). Geoscientific Model Development, 10, 2009-2030.

Photosynthesis and canopy radiation: Knorr, W.: Satellite Remote Sensing and Modelling of the global CO2 exchange of land vegetation: A synthesis study, Examensarbeiten Nr. 49, MPI for Meteorology (1998)

Land cover change: Reick, C., Raddatz, T., Brovkin, V. & Gayler, V. (2013). Representation of natural and anthropogenic land cover change in MPI-ESM. Journal of Advances in Modeling Earth Systems, 5, 459-482 , doi:10.1002/jame.20022.

Albedo scheme: Vamborg, F. S. E., V. Brovkin, and M. Claussen: The effect of a dynamic background albedo scheme on Sahel/Sahara precipitation during the mid-Holocene, Climate of the Past, 7, 117-131 (2011). doi:10.5194/cp-7-117-2011.

Wildfires: Lasslop, G., Brovkin, V., Reick, C., Bathiany, S. & Kloster, S. (2016). Multiple stable states of tree cover in a global land surface model due to a fire-vegetation feedback. Geophysical Research Letters, 43, 6324-6331.