Comparison between winter and summer sky-luminance distribution in Central Europe and in the Eastern Mediterranean

Bartzokas, A.; Kambezidis, H. D.; Darula, Stanislav; Kittler, Richard

doi:10.1016/j.jastp.2004.12.008

Cited by 35 publications

(14 citation statements)

References 13 publications

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“…This finding is in agreement with the results of Bartzokas et al (2005) who concluded that the prevailing Sky Standard for Athens, in both seasons, is V.5, namely, a cloudless polluted atmosphere-CIE Standard Clear Sky (CIE, 2003). It is apparent that for the cases classified into Cluster 1, Sky Standard V.5 dominates during the whole day.…”

Section: Discussionsupporting

confidence: 92%

“…Bartzokas et al (2005) found that the prevailing overcast Sky Standard in Athens is II.2 (overcast, moderately gradated and slight brightening towards the Sun) for winter and II.1 (overcast, moderately gradated with azimuthal uniformity) for summer. As the diurnal curves of the illuminance for the above clusters are smooth, it is inferred that during most part of the days Sky Standards II.2 or II.1 prevail.…”

Section: Discussionmentioning

confidence: 97%

“…Skyluminance modelling has attracted the interest of many researchers who have developed or improved models for clear, overcast or partly cloudy skies (Kittler et al 1997;1998;Igawa et al, 1999). Due to the limitations in the database availability, most of the daylight studies refer to local sky conditions mainly in Europe (Muneer and Angus, 1993;Fontoynont et al, 1999;Bartzokas et al, 2005), USA (Perez et al, 1993) and the Far East (Li et al, 2006;Wittkopf and Soon, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Daylight climatology in Athens, Greece: types of diurnal variation of illuminance levels

Markou

Bartzokas

Kambezidis

2009

Intl Journal of Climatology

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ABSTRACT:In the present work, the diurnal variation of illuminance levels in Athens, Greece, is studied during winter and summer. The database consists of 5-minute values of global horizontal illuminance for the period 1992-1996 recorded at the National Observatory of Athens (NOA). For each season, two sets of data are determined (sunrise to noon and noon to sunset) consisting of the semi-diurnal courses of illuminance anomalies from the mean semi-diurnal course of each day of the year. By using the multivariate statistical methods Factor Analysis and Cluster Analysis, the identification of the most characteristic modes of diurnal variation of global illuminance is attempted. It is found that six types of semi-diurnal courses (sunrise to noon and noon to sunset) of global illuminance are the most characteristic for winter, while for summer, six types of courses are found for sunrise to noon and five for noon to sunset. Some of these courses present the almost smooth ascending/descending intra-daily variation of illuminance, while others show significant disturbances during various daytime periods due to development of clouds.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Daylight climatology in Athens, Greece: types of diurnal variation of illuminance levels

Markou

Bartzokas

Kambezidis

2009

Intl Journal of Climatology

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“…In order to determine why the March and July data differ, we compared the CIE standard sky model number with the sky clearness by the Perez model and the sky index by the Igawa model [46]. The comparison is shown in the graph in Figure 18.…”

Section: Analysis Of Sky Luminance Distribution Calculation Methodsmentioning

confidence: 99%

Sky Luminance Measurements Using CCD Camera and Comparisons with Calculation Models for Predicting Indoor Illuminance

Yun

Kim

2018

Sustainability

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Abstract:In this study, we address the algorithm of the calculation formula from sky luminance distribution to vertical illuminance and indoor illuminance. To predict daylight, studies about sky luminance distributions and the DeLight daylight model were investigated. This paper compared three well-known sky distribution models (Perez model, Igawa model, and CIE standard sky model) with measured data. The charge coupled device (CCD) camera was used as a measurement method for sky luminance distribution. Indoor illuminance values calculated with those well-known sky distribution models are compared with measured indoor illuminance data. The following conclusions were obtained: (1) In the results of R 2 , mean bias error (MBE), and Cv(RMSE) analysis, the CIE standard sky model showed the lowest error rate with measured data. Between the Perez model and Igawa model, the Igawa model showed a lower error rate; (2) When we compared the sky classification of the Perez model and the Igawa model, both models classified the sky similarly to the CIE standard sky model in March. However, the classification of the sky in the CIE standard sky model, the Perez model, and the Igawa model differed in some of the July data because of high solar elevation; (3) The illuminance of the center point of the room was calculated using the well-known sky luminance distribution model, the Igawa model has a lower error rate than the Perez model in Korea.

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“…Using L z /D v for a place where high solar altitude dominates can lead to ambiguous results [11]. Bartzokas et al [12,13] modified the L z /D v sky classification method to study the daylight climate at two cities in Central Europe but a certain amount of luminance data were excluded for analysis. There are a number of climatic parameters appropriate to identify the daylight climates [14].…”

Section: Introductionmentioning

confidence: 99%

Classification of Hong Kong Prevailing Standard Skies

Li¹,

Tang²

2008

TOBCTJ

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Abstract:In 2003, the International Commission on Illumination (CIE) adopted a range of 15 standard skies covering the whole probable spectrum of usual skies in the world. A good understanding of the sky luminance distribution is essential to daylighting developments and energy-efficient building designs. This paper studies the work on the identification of Hong Kong prevailing standard skies. Ten-minute data recorded between 1999 and 2005 in Hong Kong were used for the analysis. An approach to identify a subset of 6 sky standards including overcast, partly cloudy and clear sky types was proposed. The performance of the proposed approach was evaluated against the measured data in terms of root-meansquare error (RMSE). The statistical analysis showed that the proposed method produced acceptable agreements with the measured data and the overall RMSE was computed of 30%

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Comparison between winter and summer sky-luminance distribution in Central Europe and in the Eastern Mediterranean

Cited by 35 publications

References 13 publications

Daylight climatology in Athens, Greece: types of diurnal variation of illuminance levels

Daylight climatology in Athens, Greece: types of diurnal variation of illuminance levels

Sky Luminance Measurements Using CCD Camera and Comparisons with Calculation Models for Predicting Indoor Illuminance

Classification of Hong Kong Prevailing Standard Skies

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