Urban surface model (USM)

Main page of the urban surface model under construction. Click here for first information about capabilities and model steering. Also available, the related article PALM-USM v1.0: A new urban surface model integrated into the PALM large-eddy simulation model (Resler et al., Geosci. Model Dev., 10, 3635–3659, ​10.5194/gmd-10-3635-2017 ​10.5194/gmd-10-3635-2017)

Urban surfaces (building surfaces) are simulated using a tile approach. Each surface element consists of a fraction of bare wall/ roof, window and green elements (green roofs/ facades) with underlying soil layers (green roofs only) and a bare wall/ roof structure.

The wall heat and green heat model consist of prognostic equations for the bare, window and soil temperature and the volumetric soil moisture which are solved for multiple layers. The models only take transport into account that is orthogonal to the urban surface layer orientation and no ice phase is considered. By default, the wall heat model and the green heat soil model consists of four layers each (see Fig. 1 below), in which the orthogonal heat and water transport inside the soil is modelled.

Figure 1: urban surfaces (bare, window, green) in PALM-4U