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

Ma, S.; Pitman, A. J.; Hart, Mary; Evans, Jason P.; Haghdadi, Navid; MacGill, Iain

doi:10.1002/joc.5001

Cited by 62 publications

(33 citation statements)

References 53 publications

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“…Anthropogenic heat fluxes can increase turbulence fluxes, including both sensible and the latent heat fluxes (Oke 1988). Moreover, anthropogenic heat fluxes influence surface meteorological conditions, particularly air temperature and water vapor pressure; the vertical motion of urban air flow, which in turn affects urban heat island circulation (UHIC) and dynamics and thermal dynamics of the boundary layer; and air pollutants within the urban canopy layer (Oke 1987, 1988, Ichinose et al 1999, Kikegawa et al 2003, Sailor and Lu 2004, Feng et al 2012, Salamanca et al 2014, Xie et al 2016, Ma et al 2017.…”

Section: Introductionmentioning

confidence: 99%

Effects of anthropogenic heat due to air-conditioning systems on an extreme high temperature event in Hong Kong

Wang

Sabatino

et al. 2018

Environ. Res. Lett.

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Anthropogenic heat flux is the heat generated by human activities in the urban canopy layer, which is considered the main contributor to the urban heat island (UHI). The UHI can in turn increase the use and energy consumption of air-conditioning systems. In this study, two effective methods for water-cooling air-conditioning systems in non-domestic areas, including the direct cooling system and central piped cooling towers (CPCTs), are physically based, parameterized, and implemented in a weather research and forecasting model at the city scale of Hong Kong. An extreme high temperature event (June 23-28, 2016) in the urban areas was examined, and we assessed the effects on the surface thermal environment, the interaction of sea-land breeze circulation and urban heat island circulation, boundary layer dynamics, and a possible reduction of energy consumption. The results showed that both water-cooled air-conditioning systems could reduce the 2 m air temperature by around 0.5 • C-0.8 • C during the daytime, and around 1.5 • C around 7:00-8:00 pm when the planetary boundary layer (PBL) height was confined to a few hundred meters. The CPCT contributed around 80%-90% latent heat flux and significantly increased the water vapor mixing ratio in the atmosphere by around 0.29 g kg −1 on average. The implementation of the two alternative air-conditioning systems could modify the heat and momentum of turbulence, which inhibited the evolution of the PBL height (a reduction of 100-150 m), reduced the vertical mixing, presented lower horizontal wind speed and buoyant production of turbulent kinetic energy, and reduced the strength of sea breeze and UHI circulation, which in turn affected the removal of air pollutants. Moreover, the two alternative air-conditioning systems could significantly reduce the energy consumption by around 30% during extreme high temperature events. The results of this study suggest potential UHI mitigation strategies and can be extended to other megacities to enable them to be more resilient to UHI effects. NomenclatureCOP Coefficient of performance [−] C p Specific heat of air [J K −1 kg −1 ] C w Specific heat of water at constant pressure [J K −1 kg −1 ] C sw Specific heat of sea water at constant pressure [J K −1 kg −1 ] d ai Water vapor mixing ratio of the inlet air [g kg −1 ] d ao Water vapor mixing ratio of the outlet air [g kg −1 ] e Water vapor pressure [hPa] h ai Enthalpy of the inlet air [J kg −1 ] h ao Enthalpy of the outlet air [J kg −1 ] H i out Sensible heat fluxes at each vertical level [W]

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Section: Introductionmentioning

confidence: 99%

Effects of anthropogenic heat due to air-conditioning systems on an extreme high temperature event in Hong Kong

Wang

Sabatino

et al. 2018

Environ. Res. Lett.

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“…Действие этих факторов в городах приводит, как правило, к увеличению поглощенной солнечной радиации и уменьшению уходящей тепловой, уменьшению доли скрытого и увеличению доли явного турбулентного тепла, увеличению потока теплового накопления [22,26]. В совокупности действие перечисленных факторов в литературе называют эффектами урбанизации [31] или эффектами покрытия [82].…”

Section: термический отклик городского покрывающего слоя на внешние иunclassified

“…Дополнительно к экспериментам по термической реакции UCL на эффекты городского покрытия [62,83,96] на ММ-моделях проведено большое количество экспериментов по оцениванию термического отклика на изменения AHF -слагаемого Q F в (6) [31-33, 82, 98, 103-107]. Эксперименты показали, что AHF приводит к росту T UHI , в отличие от действия городского покрова, который иногда приводит к «острову охлаждения» в дневные часы [82,107]. Для условий г. Сидней вклад AHF в T UHI в зимний период ночью может достигать 80%.…”

Section: термический отклик городского покрывающего слоя на внешние иunclassified

“…Для условий г. Сидней вклад AHF в T UHI в зимний период ночью может достигать 80%. В это время в среднем наблюдаются и максимальные значения интенсивности острова тепла [82]. Для типичного арктического города (г. Аппатиты, Россия), вклад AHF в T UHI в зимний период оценивается в 50% [106].…”

Section: термический отклик городского покрывающего слоя на внешние иunclassified

“…Эксперименты по чувствительности показали, что совместный эффект действия городского покрова и AHF не складывается из суммы действий, зависит от условий для отдельных мегаполисов, времени суток и сезона [44,82,105].…”

Section: термический отклик городского покрывающего слоя на внешние иunclassified

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Anthropogenic meso-meteorological feedbacks: a review of recent research

Гинзбург

Demchenko

2019

Известия Российской академии наук. Физика атмосферы и океана

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The anthropogenic impact on the Earths climate system is currently one of the main factors determining climate change on all spatial scales, from local to global. A lot of scientific research is devoted to the direct and indirect influence of various types of human activity on the state of the Earths climate system. Using different climate models, feedbacks that enhance or weaken anthropogenic effects in the process of global warming have been studied in enough detail. Developed in recent years regional models of climatic and meteorological processes are allowing to describe in detail the climate features in urban agglomerations and the role of feedback in the development of mesoscale atmospheric processes. This review is devoted to the description and analysis of mesoscale feedbacks in the climate system, including the energy consumption of an urban economy that depends on climatic and weather conditions, and the role of these feedbacks in the formation and dynamics of urban climate and the needs of the urban economy in energy supply.

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A building energy demand and urban land surface model

Lipson

Thatcher

Hart

et al. 2018

Quart J Royal Meteoro Soc

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Cities are unique environments where anthropogenic waste heat from energy consumption changes the dynamics of the boundary layer, affecting temperatures, pollution dispersion and buoyancy-driven flows. Although urban environments are important for societal wellbeing, there are relatively few models that link predictions of waste heat variability with urban climate interactions. This study presents the Urban Climate and Energy Model (UCLEM): a new physically based model representing important heat transfer processes between the atmosphere, external and internal urban environments, combined with a statistical model of human behaviours relating to energy use. The aim of UCLEM is to efficiently predict the climatology of different urban areas, as well as the energy used to maintain comfortable temperatures within buildings. The model is designed to be easily adaptable to a wide range of urban settings with adjustable parameters including building height, density, material thermal and radiative characteristics and vegetation fractions. We assess UCLEM's ability to predict energy consumption for a neighbourhood of Melbourne, Australia, forced by local flux tower observations and evaluated at half-hourly intervals over 12 months. Results are presented in four development stages to assess various levels of physical and behavioural model complexity. We show that more complete physical representations can improve average daily energy consumption predictions; however, sub-daily patterns of energy use are improved only by combining the physics-based model with a statistical model of human behaviour. At the final stage, as well as predicting surface-atmosphere radiant and turbulent fluxes, UCLEM estimates neighbourhood energy demand with a normalised mean error of 11.5% and a computation time on a single processor of about 1 s per simulation year. KEYWORDS anthropogenic waste heat, building energy demand, urban meteorology 1 Q J R Meteorol Soc. 2018;144:1572-1590.wileyonlinelibrary.com/journal/qj

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

Cited by 62 publications

References 53 publications

Effects of anthropogenic heat due to air-conditioning systems on an extreme high temperature event in Hong Kong

Effects of anthropogenic heat due to air-conditioning systems on an extreme high temperature event in Hong Kong

Anthropogenic meso-meteorological feedbacks: a review of recent research

A building energy demand and urban land surface model

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