Simulation of a Scandinavian basin using the diffusion transfer version of ISBA

A brief description of the two-layer frozen soil scheme and the three-layer explicit snow model used by ISBA for the PILPS(2e) experiment is presented, as well as the new soil diffusion scheme of ISBA. This new version of ISBA has a more physical description of the frozen soil processes, and it has been applied in the Torne–Kalix basins where these processes are important. The simulations of the force restore and diffusion version of ISBA (ISBA-FR and ISBA-DF, respectively) are compared to in situ observations of snow height and soil temperature at the Abisko research station, as well as to the observed riverflow at five locations. In terms of riverflow, the ISBA-DF scheme obtained results comparable to the ISBA-FR scheme, with a weakness to simulate the Abisko basin, but a good ability to simulate the Lansjaarv streamflow. However, ISBA-DF compares better than ISBA-FR to the soil temperature observed at the Abisko research station.