Sensitivity of an ecosystem model to hydrology and temperature

Byline: Annett Wolf (1,2,5), Eleanor Blyth (3), Richard Harding (3), Daniela Jacob (4), Elke Keup-Thiel (4), Holger Goettel (4), Terry Callaghan (5,6) Abstract: We tested the sensitivity of a dynamic ecosystem model (LPJ-GUESS) to the representation of soil moisture and soil temperature and to uncertainties in the prediction of precipitation and air temperature. We linked the ecosystem model with an advanced hydrological model (JULES) and used its soil moisture and soil temperature as input into the ecosystem model. We analysed these sensitivities along a latitudinal gradient in northern Russia. Differences in soil temperature and soil moisture had only little influence on the vegetation carbon fluxes, whereas the soil carbon fluxes were very sensitive to the JULES soil estimations. The sensitivity changed with latitude, showing stronger influence in the more northern grid cell. The sensitivity of modelled responses of both soil carbon fluxes and vegetation carbon fluxes to uncertainties in soil temperature were high, as both soil and vegetation carbon fluxes were strongly impacted. In contrast, uncertainties in the estimation of the amount of precipitation had little influence on the soil or vegetation carbon fluxes. The high sensitivity of soil respiration to soil temperature and moisture suggests that we should strive for a better understanding and representation of soil processes in ecosystem models to improve the reliability of predictions of future ecosystem changes. Author Affiliation: (1) Department of Physical Geography and Ecosystem Analyses, Lund University, Lund, Sweden (2) Department of Environmental Science, Universitatsstr. 22, CH-8092, Zurich, Switzerland (3) Centre for Ecology and Hydrology, Wallingford, UK (4) Max-Planck-Institut fur Meteorologie (MPI-M), Hamburg, Germany (5) Abisko Scientific Research Station, Abisko, Sweden (6) Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK Article History: Registration Date: 04/10/2007 Received Date: 06/07/2006 Accepted Date: 03/10/2007 Online Date: 27/11/2007