Impact of urbanization patterns on the local climate of a tropical city, Singapore: An ensemble study

Li, Xian‐Xiang; Koh, Tieh‐Yong; Panda, Jagabandhu; Norford, Leslie K.

doi:10.1002/2015jd024452

Cited by 98 publications

(55 citation statements)

References 54 publications

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“…They reported warming at night of >2 °C and a cooling about 1 °C during day (Georgescu et al , ), which is broadly comparable with finding of this study. A similar warming and cooling effect of urbanization of UHI effects was also found in Singapore (Li et al , ) who attributed it mainly to the greater heat storage of urban infrastructure. The proportion of heat storage relative to Rnet in urban areas ranges from 17 to 58% while this proportion reduces to 4–24% in rural areas (Cleugh and Grimmond, ).…”

Section: Discussionmentioning

confidence: 99%

The impact of an urban canopy and anthropogenic heat fluxes on Sydney's climate

Pitman

Hart

et al. 2017

Intl Journal of Climatology

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We use the Weather Research and Forecast model and estimate anthropogenic heat (AH) fluxes based on fine‐scale energy consumption data for Sydney, Australia, to investigate the effects of urbanization on temperature. We examine both the impact of urban canopy effects (UCE) and AH which in combination causes the urban heat island effect. Sydney's urban heat island (UHI) varies from −1 to >3.4 °C between day and night and between seasons. UHI intensity is highest at night and an urban cool island is often experienced during the day. UCE contributes 80% of the UHI during summer nights because of the release of stored heat from urban infrastructure that has been absorbed during the day. During the day for UCE, the reduced net radiation and greater heat storage by urban infrastructure combine to slightly cool. In contrast, AH contributes 90% of the UHI during winter nights because it does not dissipate into the higher levels of the boundary layer efficiently. The opposite applies during summer nights and during daytime in both summer and winter where heat mixes effectively into the atmosphere. Our results show contrasting impacts of UCE and AH by time of day and time of year and point to major simulation biases if only one of these phenomena is represented, or if their seasonal contributions are not accounted for separately.

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Section: Discussionmentioning

confidence: 99%

The impact of an urban canopy and anthropogenic heat fluxes on Sydney's climate

Pitman

Hart

et al. 2017

Intl Journal of Climatology

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“…The sea breeze is a meteorological phenomenon that has been extensively studied by theoretical and numerical methods in many coastal areas [ Chen et al , ; Li et al , ; Tong et al , ]. Because of Hong Kong's complex urban environment and topography, it is still crucial to accurately capture the onset and propagation of sea breeze fronts.…”

Section: Wrf‐bep‐bem Simulation Evaluationmentioning

confidence: 99%

Impact of land surface heterogeneity on urban heat island circulation and sea‐land breeze circulation in Hong Kong

et al. 2017

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Hong Kong is one of the most high‐rise and highly compact cities in the world. The urban land surface is highly heterogeneous, which creates low‐level convergence zones in urban areas, particularly the Kowloon Peninsula. The low‐level convergence zone is due to the combined effect of urban heat island circulation (UHIC) and sea‐land breeze circulation (SLBC) under weak northeasterly synoptic flow. To study the impacts of anthropogenic fluxes and built‐up areas on the local circulation, the Weather Research and Forecasting (WRF) mesoscale model is combined with the multilayer urban canopy building effect parameterization/building energy model (BEP/BEM) parameterization to produce a 3 day simulation of an air pollution episode in Hong Kong in September 2012. To better represent the city land surface features, building information is assimilated in the central part of the Kowloon Peninsula. The WRF‐BEP‐BEM model captures the 2 m temperature distribution and local wind rotation reasonably well but overestimates the 10 m wind speed with a mean bias error of 0.70 m/s. A dome‐shaped feature with a high level of moisture is captured in the convergence zones due to intensified UHIC and inflowing SLBC. The anthropogenic heat increases the air temperature by around 0.3°C up to 250 m, which in turn modifies the SLBC. A new drag coefficient based on λP, plan area per unit ground area, is tested. Besides the basic physical characteristics captured by the WRF‐BEP‐BEM model, the stagnation of wind in the lower level convergence zone is better captured by this approach than by the traditional constant value coefficient.

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“…Masson et al ., ; Lemonsu et al ., ; Bohnenstengel et al ., ; 2014; Salamanca et al ., a; b), only a few have been carried out for (sub)tropical cities (e.g. González et al ., ; Comarazamy et al ., ; Murphy et al ., ) or specifically for Singapore (Li et al ., ; ; Demuzere et al ., ; Harshan et al ., ; Liu et al ., ). Some of the studies done in Singapore were performed in uncoupled mode (Demuzere et al ., ; Harshan et al ., ; Liu et al ., ), not allowing for the assessment of potential impacts of the city feedback on the atmosphere above.…”

Section: Introductionmentioning

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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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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Impact of urbanization patterns on the local climate of a tropical city, Singapore: An ensemble study

Cited by 98 publications

References 54 publications

The impact of an urban canopy and anthropogenic heat fluxes on Sydney's climate

The impact of an urban canopy and anthropogenic heat fluxes on Sydney's climate

Impact of land surface heterogeneity on urban heat island circulation and sea‐land breeze circulation in Hong Kong

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

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