Implementation of a new urban energy budget scheme in the MetUM. Part I: Description and idealized simulations

Porson, Aurore; Clark, Peter A.; Harman, Ian N.; Best, Martin; Belcher, Stephen E.

doi:10.1002/qj.668

Cited by 79 publications

(122 citation statements)

References 43 publications

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“…The underestimation of albedo is responsible for the underestimation of K ↑ and could be because the radiation sensor footprint consists of short grass and light roofs producing an observed albedo which is slightly larger than that of the flux footprint (Roth et al ., ). This is supported by the difference in albedo being maximum around solar noon, when modelled canyon contribution to the grid albedo is dominated by the small road albedo (0.08) (Porson et al ., ), while observations are biased towards grass or roofs with a higher albedo. This bias is implicitly related to the tile approach, which does not consider the location of each tile in the grid cell.…”

Section: Resultsmentioning

confidence: 99%

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Application of MORUSES single‐layer urban canopy model in a tropical city: Results from Singapore

Simón-Moral

Dipankar

Roth

et al. 2019

Quart J Royal Meteoro Soc

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A tropical version of the high‐resolution (300 m) UK Met Office forecast model (UM) using the MORUSES urban canopy parametrization (UCP) is adapted for Singapore. High‐resolution urban surface parameters are determined using a methodology based on Voronoi polygons applied to a 3D building database. The model is evaluated for clear sky and calm conditions at the neighbourhood scale by comparing its predictions with two sources of observations: energy balance data from an eddy covariance flux tower located in a low‐rise residential area, and a network of sensors measuring screen‐level temperature across the city. The model is able to reproduce the diurnal cycle of the surface energy balance fluxes. Net radiation is overestimated which likely follows from an underestimation in cloud cover and effective surface albedo. This overestimation partly explains the overestimation of the sensible‐ and latent‐heat fluxes. The higher model sensible‐heat flux is further hypothesised to be related to the overestimation of modelled canyon sensible‐heat flux. Its peak exhibits a 1 h delay, similar to simulated roof and canyon surface temperature. The model captures the diurnal cycle of temperature at a height of 20.5 m above ground and at screen level. A night‐time cold bias of 0.1–1.1 K and an overestimation of the daytime peak value are observed at both heights. These deviations are smaller than those predicted by other UCPs reported in the literature. A simple method to estimate the capability of an urban model to qualitatively distinguish screen‐level temperature differences across different urban morphologies is developed which shows that MORUSES is clearly able to represent the impacts of different neighbourhoods on the thermal environment.

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Section: Resultsmentioning

confidence: 99%

“…This parametrization is based on Harman et al . (), rewriting the equations in order to make the resistances independent of canyon orientation (Porson et al ., ).…”

Section: Urban Modelling Systemmentioning

confidence: 99%

Application of MORUSES single‐layer urban canopy model in a tropical city: Results from Singapore

Simón-Moral

Dipankar

Roth

et al. 2019

Quart J Royal Meteoro Soc

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“…These urban canopy models are integrated into global or mesoscale models. Examples include Community Land Model-Urban (CLM-U) in Community Atmospheric Model (Oleson et al 2008;Ching 2013), Met Office Reading Urban Surface Exchange Scheme (MORUSES) in Met Office Unified Model (Porson et al 2010), Town Energy Balance (TEB) in MesoNH model (Masson 2000), and the one which has been used in present study, the single-layer urban canopy model coupled with Weather Research and Forecasting (WRF) model (Chen et al 2011a). …”

Section: Introductionmentioning

confidence: 99%

WRF model evaluation for the urban heat island assessment under varying land use/land cover and reference site conditions

Bhati

Mohan

2015

Theor Appl Climatol

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Urban heat island effect in Delhi has been assessed using Weather Research and Forecasting (WRF v3.5) coupled with urban canopy model (UCM) focusing on air temperature and surface skin temperature. The estimated heat island intensities for different land use/land cover (LULC) have been compared with those derived from in situ and satellite observations. The model performs reasonably well for urban heat island intensity (UHI) estimation and is able to reproduce trend of UHI for urban areas. There is a significant improvement in model performance with inclusion of UCM which results in reduction in root mean-squared errors (RMSE) for temperatures from 1.63°C (2.89°C) to 1.13°C (2.75°C) for urban (non-urban) areas. Modification of LULC also improves performance for non-urban areas. High UHI zones and top 3 hotspots are captured well by the model. The relevance of selecting a reference point at the periphery of the city away from populated and built-up areas for UHI estimation is examined in the context of rapidly growing cities where rural areas are transforming fast into built-up areas, and reference site may not be appropriate for future years. UHI estimated by WRF model (with and without UCM) with respect to reference rural site compares well with the UHI based on observed in situ data. An alternative methodology is explored using a green area with minimum temperature within the city as a reference site. This alternative methodology works well with observed UHIs and WRF-UCM-simulated UHIs but has poor performance for WRF-simulated UHIs. It is concluded that WRF model can be applied for UHI estimation with classical methodology based on rural reference site. In general, many times WRF model performs satisfactorily, though WRF-UCM always shows a better performance. Hence, inclusion of appropriate representation of urban canopies and land use-land cover is important for improving predictive capabilities of the mesoscale models.

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“…Recently, mesoscale meteorological and environmental models have undergone rapid development by the inclusion of urban canopy models (e.g., Masson, 2000;Kusaka et al, 2001;Martilli et al, 2002;Lee and Park, 2008;Oleson et al, 2008;Porson et al, 2010;Lee, 2011;Ryu et al, 2011) for better representation of urban land-surface processes (e.g., . Along with numerical model development, quantitative validation of surface-layer turbulent fluxes modeled by 3D mesoscale meteorological models is very important to improving forecast skill, as well as understanding boundary layer structures.…”

Section: Discussionmentioning

confidence: 99%

Estimation of turbulent sensible heat and momentum fluxes over a heterogeneous urban area using a large aperture scintillometer

Lee

Kim

2015

Adv. Atmos. Sci.

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The accurate determination of surface-layer turbulent fluxes over urban areas is critical to understanding urban boundary layer (UBL) evolution. In this study, a remote-sensing technique using a large aperture scintillometer (LAS) was investigated to estimate surface-layer turbulent fluxes over a highly heterogeneous urban area. The LAS system, with an optical path length of 2.1 km, was deployed in an urban area characterized by a complicated land-use mix (residential houses, water body, bare ground, etc.). The turbulent sensible heat (Q H ) and momentum fluxes (τ) were estimated from the scintillation measurements obtained from the LAS system during the cold season. Three-dimensional LAS footprint modeling was introduced to identify the source areas ("footprint") of the estimated turbulent fluxes. The analysis results showed that the LAS-derived turbulent fluxes for the highly heterogeneous urban area revealed reasonable temporal variation during daytime on clear days, in comparison to the land-surface process-resolving numerical modeling. A series of sensitivity tests indicated that the overall uncertainty in the LAS-derived daytime Q H was within 20%-30% in terms of the influence of input parameters and the nondimensional similarity function for the temperature structure function parameter, while the estimation errors in τ were less sensitive to the factors of influence, except aerodynamic roughness length. The 3D LAS footprint modeling characterized the source areas of the LAS-derived turbulent fluxes in the heterogeneous urban area, revealing that the representative spatial scales of the LAS system deployed with the 2.1 km optical path distance ranged from 0.2 to 2 km 2 (a "micro-α scale"), depending on local meteorological conditions. Citation: Lee, S.-H., J.-H. Lee, and B.-Y. Kim, 2015: Estimation of turbulent sensible heat and momentum fluxes over a heterogeneous urban area using a large aperture scintillometer.

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Implementation of a new urban energy budget scheme in the MetUM. Part I: Description and idealized simulations

Cited by 79 publications

References 43 publications

Application of MORUSES single‐layer urban canopy model in a tropical city: Results from Singapore

Application of MORUSES single‐layer urban canopy model in a tropical city: Results from Singapore

WRF model evaluation for the urban heat island assessment under varying land use/land cover and reference site conditions

Estimation of turbulent sensible heat and momentum fluxes over a heterogeneous urban area using a large aperture scintillometer

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