Modelling of climate response to increased forest cover in Southern Norway
Boreal forest is a key player in the climate of northern latitudes. Surveys of tree- and forest-lines in southern Norway since 1910s have revealed that the forest- and treelines have risen to higher elevations, and that forests has expanded into previous mountain regions (e.g. the top two in the figure). The density of the forest has also increased, causing an increase in the standing volume of about 200%. Changes in vegetation cover affect the local surface energy balance through changes in albedo and turbulent fluxes of energy and humidity. The darker color of the forest and the protrusion of the snow cover increase absorption of solar radiation. The change in vegetation influence the surface roughness with implications for the mechanical generation of turbulent eddies, and thus the sensible and latent heat fluxes. Forest expansion will also change the evapotranspiration and the interception of rainfall further affecting the latent heat flux.
Detailed maps based on new data from historical forest surveys (at the bottom of the figure) will be used as input to NoahMP, the land module of the WRF model (a numerical weather prediction model). NoahMP calculates the surface energy fluxes consistent with the meteorological variables in the boundary layer of the atmosphere. In the project, the student will implement the vegetation changes (areal extent and physical parameters) in NoahMP and in a first phase perform off-line simulations to quantify the changes in the surface energy balance. In a second phase, the NoahMP will be run coupled in WRF enabling a more complete quantification of the impact on local climate.
The calculated impacts will be evaluated and compared relative to the climate impacts calculated from the long-term changes in CO2 and other climate forcers as part of the CMIP6 project.
The student will work together with a master student at the Natural History Museum (NHM) who will work with the ecology of forest dynamics, generate detailed maps/models and characteristics of the forest expansion.