Скачать или смотреть Characterizing carbon and water fluxes in the Arctic forest using plant hydraulics parameterization.

Stomatal conductance in terrestrial biosphere models (TBMs) plays a critical role in accurately simulating carbon and water fluxes, and for evaluating the impacts of climate change on land surface-atmosphere interactions. Climate change impacts such as more frequent heat waves and drought conditions challenge TBMs and need to be investigated thoroughly, especially in the rapidly changing arctic boreal forest. Terrestrial biosphere models such as the Canadian Land Surface Scheme Including Biogeochemical Cycles (CLASSIC) often employ empirical formulations that link soil moisture to stomatal conductance. These soil moisture-based empirical approaches typically perform poorly under drought conditions.

Our study implemented an explicit plant hydraulics parameterization in CLASSIC to connect the soil-plant-atmosphere continuum through plant hydraulic traits, i.e., stomatal optimization based on xylem hydraulics (SOX), resulting in CLASSICSOX. Model performance was evaluated at eight arctic boreal forest sites; three are permafrost-free, four are in the discontinuous permafrost zone, and one is in the continuous permafrost zone. Compared to the default CLASSIC, simulated gross primary production (GPP) improved at all eight sites with CLASSICSOX. Drought conditions at the eight sites were identified using the Palmer Drought Severity Index, and the results showed improvement in simulated GPP during drought conditions. Overall, the SOX parameterization achieved improved results compared to CLASSIC by-default at all sites, specifically for the sites located at the continuous and discontinuous permafrost zone.