Surface Urban Energy and Water Balance Scheme (SUEWS) (Järvi et al. 2011) is able to simulate the urban radiation, energy and water balances using only commonly measured meteorological variables and information about the surface cover. SUEWS utilizes an evaporation-interception approach (Grimmond et al. 1991), similar to that used in forests, to model evaporation from urban surfaces.
The model uses seven surface types: paved, buildings, evergreen trees/shrubs, deciduous trees/shrubs, grass, bare soil and water. The surface state for each surface type at each time step is calculated from the running water balance of the canopy where the evaporation is calculated from the Penman-Monteith equation. The soil moisture below each surface type (excluding water) is taken into account.
Horizontal movement of water above and below ground level is allowed. The user can specify the model timestep, but 5 min is strongly recommended. The main output file is provided at a resolution of 60 min by default. Timestamps refer to the end of the averaging period. The model provides the radiation and energy balance components, surface and soil wetness, surface and soil runoff and the drainage for each surface (see section 5).
The following sub-models are used within SUEWS: 1. NARP (Net All-wave Radiation Parameterization, Offerle et al. 2003, Loridan et al. 2010) radiation scheme. 2. OHM (Objective Hysteresis Model, Grimmond et al. 1991, Grimmond & Oke 1999a, 2002) for the storage heat flux. 3. LUMPS (Local-scale Urban Meteorological Parameterization Scheme, Grimmond & Oke 2002) does the initial turbulent sensible and latent heat fluxes calculation for stability (Appendix D gives the differences between SUEWS and LUMPS). Note both models’ outputs are provided in all runs. 4. Two simple anthropogenic heat flux models (Järvi et al. 2011). 5. A simple urban water-use model (Grimmond and Oke 1991). 6. A convective boundary layer (CBL) slab model (Cleugh and Grimmond 2001) calculates the CBL height, temperature and humidity during daytime (Onomura et al. 2015) 7. A snowmelt model (Järvi et al. 2014). 8. SOLWEIG: The solar and longwave environmental irradiance geometry model (Lindberg et al. 2008, Lindberg and Grimmond 2011), a 2D radiation model to estimate mean radiant temperature. 9. ESTM (Element Surface Temperature Method, Offerle et al., 2005) for the storage heat flux. This submodel could be switched to OHM or AhOHM.
The model distributed with this manual can be run in two standard ways: 1) for an individual area 2) for multiple areas that are contiguous There is no requirement for the areas to be of any particular shape but here we refer to them as ‘grids’.
Model applicability: Local scale – so forcing data should be above the height of the roughness elements (trees, buildings).