Vector model for calculation of solar radiation intensity and sums incident on tilted surfaces. Identification for the three sky condition in Warsaw

Owczarek, Stefan

doi:10.1016/s0960-1481(96)00117-6

Cited by 12 publications

(7 citation statements)

References 7 publications

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“…Standard solar geometry schemes are used to determine the facet-averaged direct solar fluxes (e.g. Owczarek 1997). The impact of geometry on the long-wave and diffuse solar fluxes, including multiple reflections, is accounted for using the matrix method for grey-body radiative transfer (e.g.…”

Section: (B) Energy Balance Of the Roughness Sublayermentioning

confidence: 99%

The surface energy balance and boundary layer over urban street canyons

Harman¹,

Belcher²

2006

Quart J Royal Meteoro Soc

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SUMMARYA model is developed for the energy balance of an urban area, represented as a sequence of two-dimensional street canyons. The model incorporates a novel formulation for the sensible-heat flux, that has previously been validated against wind tunnel models, and a formulation for radiation that includes multiple reflections and shadowing. This energy balance model is coupled to a model for the atmospheric boundary layer. Results are analysed to establish how the physical processes combine to produce the observed features of urban climate, and to establish the roles of building form and fabric on the urban modification to climate.Over a diurnal cycle there are morning and evening transition periods when the net flux of radiation is largely balanced by the flux of heat into the surface. The urban surface has a large surface area in contact with the air, and hence a large active heat capacity, and so the urban area needs to absorb a larger amount of heat than a rural area to change the surface temperature. The morning and evening transitions are therefore prolonged over urban areas, delaying the onset of convective or stable boundary layers after sunrise and sunset. The model shows that the energy balance of the roof behaves very differently from the combined energy balance of the street canyon system of walls and street. The sensible-heat flux from the street canyon into the boundary layer is increased by the increased surface area, but is decreased by the buildings reducing the local flow speeds. The net result is that, for the two-dimensional geometry investigated here, the sensible-heat flux from the canyon is not strongly sensitive to canyon geometry. The sensible-heat flux from the roof is larger than from the street, and so the total sensible-heat flux into the boundary layer, and hence also the air temperature, is strongly dependent on the fraction of plan area occupied by roofs. The radiation budget of the street canyon, which largely drives the temperatures of the canyon surfaces, is significantly changed by the limited sky view and multiple reflections caused by the local building form. The canyon surface temperatures thus depend strongly on local building morphology.Finally, two mechanisms are suggested for how urban areas might maintain a positive sensible-heat flux at night. Firstly, if the roof material has much lower heat capacity than the street canyon surfaces, then the roof can cool the boundary-layer air faster than the street canyon surfaces cool, leading to a positive heat flux out of the street canyon. Secondly, advection decouples the boundary layer from the local surface energy balance. In this way, cool air, perhaps from a rural area, advected on to an urban surface can lead to a positive sensible-heat flux which then tends to neutralize any stable stratification in the boundary layer.

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Section: (B) Energy Balance Of the Roughness Sublayermentioning

confidence: 99%

The surface energy balance and boundary layer over urban street canyons

Harman¹,

Belcher²

2006

Quart J Royal Meteoro Soc

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“…2(a). The two modes in the distribution of C are produced by cloudy times, when radiation is indirect, and cloud-free times, when radiation is direct (Owczarek, 1997). For illustration, Fig.…”

Section: Introductionmentioning

confidence: 99%

Non-Linear Autoregressive Time Series with Multivariate Gaussian Mixtures as Marginal Distributions

Glasbey

2001

Journal of the Royal Statistical Society Series C: Applied Statistics

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“…appropriate values for Warsaw and Belsk were calculated using the formula described by Duffie and Beckmann (2013). this method for calculating extra-terrestrial (potential) solar radiation was also used by Robaa (2009) and Kejna et al (2014a), and the results are convergent with the values determined by other methods (Owczarek 1993(Owczarek , 1997(Owczarek , 2002Bzowska & Kossecka 1993). On the basis of the measured values of the gSR and sunshine duration in Warsaw and Belsk, and the values of potential gSR and potential sunshine duration, the values of relative gSR and relative sunshine duration in percentages were calculated for both locations.…”

Section: Methodsmentioning

confidence: 91%

The seasonal variability of the amount of global solar radiation reaching the ground in urban and rural areas on the example of Warsaw and Belsk

Nelken

Leziak

2016

Miscellanea Geographica

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The aim of this paper is to determine the contemporary differences in the inflow of global solar radiation in Warsaw (urban station) and Belsk (rural station). The meteorological data used comprised daily sums of global solar radiation (in MJ•m−2) and the duration of sunshine (in hours) for the period 2008 2014. On clear days in spring and summer, the rural area receives more solar radiation in comparison to the urban area, whereas in autumn a reverse relationship occurs. On cloudy days in all seasons, the rural area receives more solar radiation than the urban area, and the relationship is the strongest in winter. Differences between urban and rural areas on cloudy days are smaller than those observed on clear days.

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Vector model for calculation of solar radiation intensity and sums incident on tilted surfaces. Identification for the three sky condition in Warsaw

Cited by 12 publications

References 7 publications

The surface energy balance and boundary layer over urban street canyons

The surface energy balance and boundary layer over urban street canyons

Non-Linear Autoregressive Time Series with Multivariate Gaussian Mixtures as Marginal Distributions

The seasonal variability of the amount of global solar radiation reaching the ground in urban and rural areas on the example of Warsaw and Belsk

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