Energy and water balances in boreal forest with discontinuous permafrost: Implementation of a physically-based hydrological model at sites with varying disturbance histories

In warming Alaskan boreal forests, changing disturbance regimes are altering permafrost, carbon and vegetation dynamics. Accurately modeling energy and water fluxes is a critical component of understanding and predicting changes to these high-latitude ecosystems. Here, we present the implementation of the physically-based Simultaneous Heat and Water (SHAW) model at the Bonanza Creek Long Term Ecological Research station. At four upland sites in the discontinuous permafrost zone with varying fire histories, vegetation structure, and permafrost presence/absence, SHAW was tested using 7 years of meteorological, vegetation, soil moisture, and soil temperature data. We will present results of model validation against depth profiles of soil moisture and temperature at three boreal forest sites, and depth to permafrost at one site. We will also present a sensitivity analysis to quantify the importance of key site parameters, and how the relative importance of these parameters differs between permafrost and non-permafrost sites. Results of this model implementation will inform the integration of SHAW with a forest simulation (LANDIS-II) and permafrost (Geophysical Institute Permafrost Laboratory (GIPL) model to improve our understanding of the effects of changing fire regimes on permafrost and carbon dynamics across the boreal forests of interior Alaska.