Evaluation of snow conditions modelling for various LCZ types

Snow conditions in cities have received little attention, while they were extensively studied on natural surfaces with several model intercomparison projects. This short article explores how improvements in snow parameterisations lead to a better simulation of the energy balance for various LCZ types. Thanks to urban sites instrumented by tower fluxes gathered by the Urban-PLUMBER intercomparison, we have been able to test the Town Energy Balance (TEB) urban canopy model behaviour, consistency, and performance on 9 cold winter climate urban sites located on America, Europe and Asia. TEB has recently been upgraded with a multilayer snow model on the road surface. This, associated with a new a simple snow removal parameterisation improves the model simulations, especially on the overall town albedo and the subsequent net radiation and energy fluxes. This comparison on 9 urban sites of various densities also suggests that in dense neighbourhoods (LCZ2), the extension and duration of the snow mantel on roofs are too large. It would be necessary to take into account the impact of pitched roofs on snow shedding. Other effects as snow darkening and or improved parameterisation of the snow removal may also be studied to help to overcome the current model limitations. • Winter cold cities simulations are improved thanks to the Urban-PLUMBER project. • Snow removal parameterisation improve the simulated the winter town albedo. • In winter, anthropogenic impacts limit the town albedo.