Urban surface cover determined with airborne lidar at 2m resolution – Implications for surface energy balance modelling

Urban Climate ◽  
2015 ◽  
Vol 13 ◽  
pp. 52-72 ◽  
Author(s):  
Annika Nordbo ◽  
Petteri Karsisto ◽  
Leena Matikainen ◽  
Curtis R. Wood ◽  
Leena Järvi
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Airborne Lidar ◽  
Urban Surface ◽  
Surface Cover

scholarly journals A New Single-Layer Urban Canopy Model for Use in Mesoscale Atmospheric Models

2011 ◽  
Vol 50 (9) ◽  
pp. 1773-1794 ◽  
Author(s):  
Young-Hee Ryu ◽  
Jong-Jin Baik ◽  
Sang-Hyun Lee
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Single Layer ◽  
Urban Canopy ◽  
Heat Fluxes ◽  
Urban Surface ◽  
Urban Canopy Model ◽  
Canopy Model ◽  
Urban Surface Energy Balance

AbstractA new single-layer urban canopy model for use in mesoscale atmospheric models is developed and validated. The urban canopy model represents a built-up area as a street canyon, two facing buildings, and a road. In this model, the two facing walls are divided into sunlit and shaded walls on the basis of solar azimuth angle and canyon orientation, and individual surface temperature and energy budget are calculated for each wall. In addition, for better estimation of turbulent energy exchange within the canyon, a computational fluid dynamics model is employed to incorporate the effects of canyon aspect ratio (height-to-width ratio) and reference wind direction on canyon wind speed. The model contains the essential physical processes occurring in an urban canopy: absorption and reflection of shortwave and longwave radiation, exchanges of turbulent energy and water between surfaces (roof, two facing walls, and road) and adjacent air, and heat transfer by conduction through substrates. The developed urban canopy model is validated using datasets obtained at two urban sites: Marseille, France, and Basel, Switzerland. The model satisfactorily reproduces canyon air temperatures, surface temperatures, net radiation, sensible heat fluxes, latent heat fluxes, and storage heat fluxes for both sites. Extensive experiments are conducted to examine the sensitivities of the urban surface energy balance to meteorological factors and urban surface parameters. The reference wind speed is found to be a more crucial meteorological factor than the reference air temperature in altering urban surface energy balance, especially for weak winds. The urban surface energy balance is most sensitive to the roof albedo among urban surface parameters. The roof fraction, canyon aspect ratio, and ratio of roughness length for momentum to that for heat for the roof play important roles in altering urban surface energy balance.

scholarly journals Parametrisation of the variety of human behaviour related to building energy consumption in the Town Energy Balance (SURFEX-TEB v. 8.2)

2017 ◽  
Vol 10 (7) ◽  
pp. 2801-2831 ◽  
Author(s):  
Robert Schoetter ◽  
Valéry Masson ◽  
Alexis Bourgeois ◽  
Margot Pellegrino ◽  
Jean-Pierre Lévy
Keyword(s):  
Energy Consumption ◽  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Urban Climate ◽  
Building Energy ◽  
Human Behaviour ◽  
Urban Surface ◽  
Building Energy Consumption ◽  
The Town

Abstract. The anthropogenic heat flux can be an important part of the urban surface energy balance. Some of it is due to energy consumption inside buildings, which depends on building use and human behaviour, both of which are very heterogeneous in most urban areas. Urban canopy parametrisations (UCP), such as the Town Energy Balance (TEB), parametrise the effect of the buildings on the urban surface energy balance. They contain a simple building energy model. However, the variety of building use and human behaviour at grid point scale has not yet been represented in state of the art UCPs. In this study, we describe how we enhance the Town Energy Balance in order to take fractional building use and human behaviour into account. We describe how we parametrise different behaviours and initialise the model for applications in France. We evaluate the spatio-temporal variability of the simulated building energy consumption for the city of Toulouse. We show that a more detailed description of building use and human behaviour enhances the simulation results. The model developments lay the groundwork for simulations of coupled urban climate and building energy consumption which are relevant for both the urban climate and the climate change mitigation and adaptation communities.

scholarly journals Parametrisation of the variety of human behaviour related to building energy consumption in TEB (SURFEX v. 8.2)

2017 ◽  
Author(s):  
Robert Schoetter ◽  
Valéry Masson ◽  
Alexis Bourgeois ◽  
Margot Pellegrino ◽  
Jean-Pierre Lévy
Keyword(s):  
Energy Consumption ◽  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Urban Climate ◽  
Building Energy ◽  
Human Behaviour ◽  
Urban Surface ◽  
Building Energy Consumption ◽  
The Town

Abstract. The anthropogenic heat flux can be an important part of the urban surface energy balance. Some of it is due to energy consumption inside buildings, which depends on building use and human behaviour, both of which are very heterogeneous in most urban areas. Urban Canopy Parametrisations (UCP), such as the Town Energy Balance (TEB), parametrise the effect of the buildings on the urban surface energy balance. They contain a simple building energy model. However, the variety of building use and human behaviour at grid point scale has not yet been represented in state of the art UCPs. In this study, we describe how we enhance the Town Energy Balance in order to take fractional building use and human behaviour into account. We describe how we parametrise different behaviours and initialise the model for applications in France. We evaluate the spatio-temporal variability of the simulated building energy consumption for the city of Toulouse. We show that a more detailed description of building use and human behaviour enhances the simulation results. The model developments lay the groundwork for simulations of coupled urban climate and building energy consumption which are relevant for both the urban climate and the climate change mitigation and adaptation communities.

Analysis of observations on the urban surface energy balance in Beijing

2012 ◽  
Vol 55 (11) ◽  
pp. 1881-1890 ◽  
Author(s):  
ShiGuang Miao ◽  
JunXia Dou ◽  
Fei Chen ◽  
Ju Li ◽  
AiGuo Li
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Urban Surface ◽  
Urban Surface Energy Balance

scholarly journals Using climate reanalysis data in conjunction with multi-temporal satellite thermal imagery to derive supraglacial debris thickness changes from energy-balance modelling

2021 ◽  
pp. 1-19
Author(s):  
Rebecca L. Stewart ◽  
Matthew Westoby ◽  
Francesca Pellicciotti ◽  
Ann Rowan ◽  
Darrel Swift ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Current Knowledge ◽  
Meteorological Data ◽  
Reanalysis Data ◽  
Balance Model ◽  
Thermal Imagery ◽  
Thickness Estimation ◽  
Miage Glacier

Abstract Surface energy-balance models are commonly used in conjunction with satellite thermal imagery to estimate supraglacial debris thickness. Removing the need for local meteorological data in the debris thickness estimation workflow could improve the versatility and spatiotemporal application of debris thickness estimation. We evaluate the use of regional reanalysis data to derive debris thickness for two mountain glaciers using a surface energy-balance model. Results forced using ERA-5 agree with AWS-derived estimates to within 0.01 ± 0.05 m for Miage Glacier, Italy, and 0.01 ± 0.02 m for Khumbu Glacier, Nepal. ERA-5 data were then used to estimate spatiotemporal changes in debris thickness over a ~20-year period for Miage Glacier, Khumbu Glacier and Haut Glacier d'Arolla, Switzerland. We observe significant increases in debris thickness at the terminus for Haut Glacier d'Arolla and at the margins of the expanding debris cover at all glaciers. While simulated debris thickness was underestimated compared to point measurements in areas of thick debris, our approach can reconstruct glacier-scale debris thickness distribution and its temporal evolution over multiple decades. We find significant changes in debris thickness over areas of thin debris, areas susceptible to high ablation rates, where current knowledge of debris evolution is limited.

scholarly journals Application of an improved surface energy balance model to two large valley glaciers in the St. Elias Mountains, Yukon

2020 ◽  
pp. 1-16
Author(s):  
Tim Hill ◽  
Christine F. Dow ◽  
Eleanor A. Bash ◽  
Luke Copland
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Shortwave Radiation ◽  
Balance Model ◽  
Landsat 8 ◽  
Glacier Surface ◽  
Ice Dynamics ◽  
Surface Melt

Abstract Glacier surficial melt rates are commonly modelled using surface energy balance (SEB) models, with outputs applied to extend point-based mass-balance measurements to regional scales, assess water resource availability, examine supraglacial hydrology and to investigate the relationship between surface melt and ice dynamics. We present an improved SEB model that addresses the primary limitations of existing models by: (1) deriving high-resolution (30 m) surface albedo from Landsat 8 imagery, (2) calculating shadows cast onto the glacier surface by high-relief topography to model incident shortwave radiation, (3) developing an algorithm to map debris sufficiently thick to insulate the glacier surface and (4) presenting a formulation of the SEB model coupled to a subsurface heat conduction model. We drive the model with 6 years of in situ meteorological data from Kaskawulsh Glacier and Nàłùdäy (Lowell) Glacier in the St. Elias Mountains, Yukon, Canada, and validate outputs against in situ measurements. Modelled seasonal melt agrees with observations within 9% across a range of elevations on both glaciers in years with high-quality in situ observations. We recommend applying the model to investigate the impacts of surface melt for individual glaciers when sufficient input data are available.

scholarly journals A Semiempirical Microscale Model of the Surface Energy Balance and Its Application to Two Urban Rooftops

2008 ◽  
Vol 47 (3) ◽  
pp. 819-834 ◽  
Author(s):  
Timothy M. Barzyk ◽  
John E. Frederick
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Balance Model ◽  
Site Specific ◽  
City Hall ◽  
Microscale Model ◽  
Dry Conditions ◽  
Stone Concrete ◽  
The City

Abstract Individual structures within the same local-scale (102–104 m) environment may experience different microscale (<103 m) climates. Urban microclimate variations are often a result of site-specific features, including spatial and material characteristics of surfaces and surrounding structures. A semiempirical surface energy balance model is presented that incorporates radiative and meteorological measurements to statistically parameterize energy fluxes that are not measured directly, including sensible heat transport, storage heat flux through conduction, and evaporation (assumed to be negligible under dry conditions). Two Chicago rooftops were chosen for detailed study. The City Hall site was located in an intensely developed urban area characterized by close-set high-rise buildings. The University rooftop was in a highly developed area characterized by three- to seven-story buildings of stone, concrete, and brick construction. Two identical sets of instruments recorded measurements contemporaneously from these rooftops during summer 2005, and results from the week of 29 July to 5 August are presented here. The model explains 83.7% and 96% of the variance for the City Hall and University sites, respectively. Results apply to a surface area of approximately 1260 m2, at length scales similar to the dimensions of built structures and other urban elements. A site intercomparison revealed variations in surface energy balance components caused by site-specific features and demonstrated the relevance of the model to urban applications.

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