Biosphere-atmosphere interactions in high-latitude regions

Abstract:

The impact of interactive vegetation phenology on land-atmosphere interactions in high-latitude regions is assessed by comparing two pan-arctic simulations of the fifth generation Canadian Regional Climate Model (CRCM5) – one with interactive phenology and the other with prescribed phenology, both driven by ECMWF reanalysis data. Both simulations include soil organic matter and use a deep soil configuration for better representation of permafrost. Interactive phenology is represented in CRCM5 by means of the Canadian Terrestrial Ecosystem Model (CTEM), which is coupled to the Canadian Land Surface Scheme (CLASS). Previous offline simulations of CTEM coupled to CLASS, driven by reanalysis data, show that these models have significant skill in simulating carbon pools and fluxes, as well as permafrost extent and active layer thickness.

The performance of the CRCM5 simulations is first assessed by comparing simulated fields, e.g. 2m temperature, precipitation, snow water equivalent, leaf area index, primary productivity, soil carbon and permafrost, to observation-based datasets. The impact of interactive phenology on the simulated land surface and climate is then assessed by focusing on the biophysical feedbacks. The differences in the representation of interannual variability are also analyzed in order to quantify the added value of interactive phenology.