Sensitivity of an ecosystem model to hydrology and temperature

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.

Influence of changed vegetations fields on regional climate simulations in the Barents Sea Region

“…The models require absolute values and need the present day climate conditions as accurately as possible in order to examine the impact of climate change. For instance, a temperature bias results in a significant impact on vegetation carbon uptake (Wolf et al 2007). Therefore the meteorological data of near surface temperature and precipitation for the future climate were corrected with a method similar to the "delta change approach" (e.g.…”

“…The forest distribution of Hagemann (2002) can be considered as quasi-observed dataset (satellite data product). The forest distribution of LPJ-GUESS is a state of equilibrium derived after a 1,000-year spin-up period, driven by the meteorological quantities from the CRU timeseries from 1901 to 1930 repeatedly to provide the climate input for the spin-up (Wolf et al 2007). LPJ-GUESS provides a "present-potential" vegetation, without human influence, e. g. deforestation and additional simulation biases.…”

“…These models, which are often referred to as dynamic vegetation models, are IBIS (Foley et al 1996) and LPJ (Sitch et al 2003). The BALANCE project investigates both the effect of changed vegetation on climate change (biogeography) and changes in the carbon cycle (biogeochemistry) by Wolf et al (2007). Therefore we used a dynamic vegetation model in our study.…”

Five years of land surface phenology in a large-scale flooding and draining manipulation in a coastal Arctic ecosystem

“…LSP is a key indicator of ecosystem dynamics that are susceptible to environmental change (Myneni et al, 1997). Detecting biotic responses such as phenology to a changing environment is essential for understanding the consequences of global change including impacts to ecosystem carbon balance (Merbold et al, 2009), (Wolf et al, 2008) energy balance (Euskirchen et al, 2007), (Chapin et al, 2005), and biodiversity (Foster et al 2010). This study aimed to monitor seasonal and interannual trends in LSP and understand how LSP responds to altered surface hydrology and interannual climatic and other environmental variability using reflectance data from the robotic tram system.…”

Assessing climate change impacts in the European north

“…The LPJ-GUESS vegetation model was also utilized to investigate possible changes in insect herbivory and its impact on vegetation growth and productivity as a result of increasing temperatures (Wolf et al 2008b). The results suggest that the predicted temperature variation in the Barents Sea Region may lead to a potential impact that will be strongest in the eastern (Russian) part of our study region.…”