- 1Transport, Health and Urban Systems (THUS) research lab, Faculty of Architecture, Building and Planning, University of Melbourne, Melbourne, Australia (kerry.nice@unimelb.edu.au)
- 2Institute for Water and Environment, Karlsruhe Institute of Technology, Karlsruhe, Germany (harro.jongen@kit.edu)
- 3Institute of Ecology and Landscape, Department of Landscape Architecture, Hochschule Weihenstephan-Triesdorf, Freising, Germany (kristian.foerster@hswt.de)
Growing adoption of integrated water management and urban greening strategies provide an opportunity for urban heat amelioration. Planning the use of and optimizing the benefits from these techniques, under present day and future climate conditions, requires suitable modelling tools. However, the Urban-PLUMBER project found that most land surface models fail to properly represent urban water processes (Jongen et al., 2024), including water balance closure, evapotranspiration, water storage, and surface runoff, leading to lower modelling performance. These shortcomings may be overcome by implementing a soil water balance model component into existing land surface models. Here, we adapted the soil water balance model, SIMPEL (Hörmann et al., 2007) for integration into land surface models. SIMPEL's stand-alone performance was evaluated against observations of turf grass irrigation trials conducted in 2021 and 2022 (Cheung et al., 2024) and showed good skill in predicting infiltration and soil moisture storage levels under a variety of precipitation and irrigation scenarios.
After the initial integration of the SIMPEL module into the TARGET local scaled model (Broadbent et al., 2019), TARGET shows increased accuracy compared to Phase 1 of the Urban-PLUMBER project (Lipson et al., 2023), using the Coutts et al. (2007) AU-Preston dataset.
As a standalone and computationally efficient model component, SIMPEL is suitable to be added as a module to a wide range of models to overcome the shortcomings found around water balance representation, ensuring water balance closure and internal water storage consistency. Future work is planned to improve the coupling with TARGET and to add SIMPEL to the VTUF-3D micro-scale model. Work is also planned to improve performance in urban sub-surface runoff representations.
References
Broadbent et al. (2019) 10.5194/gmd-2018-177
Cheung et al. (2024) 10.1016/j.uclim.2024.101914
Coutts et al. (2007) 10.1175/JAM2462.1
Hörmann et al. (2007) 10.1016/j.ecolmodel.2007.07.019
Jongen et al. (2024) 10.1029/2024MS004231
Lipson et al. (2023) 10.1002/qj.4589
