1、StandardSpatial Distribution of Daylight -CIE Standard General SkyRpartition spatiale de la lumire du jour - Ciel gnral normalis CIERumliche Verteilung des Tageslichts - Allgemeiner Himmel nach CIE genormtCIE Standards are copyrighted and shall not be reproduced in any form, entirely or partly, with
2、outthe explicit agreement of the CIE.CIE Central Bureau, Vienna S 011/E:2003Kegelgasse 27, A-1030 Vienna, AustriaUDC: 628.9.02 Descriptor: Light from celestial bodies and the skyCIE S 011/E:2003CIE S 011/E:2003II g211 CIE, 2003 - All rights reservedg211 CIE 2003All rights reserved. Unless otherwise
3、specified, no part of this publication may be reproducedor utilized in any form or by any means, electronic or mechanical, including photocopying andmicrofilm, without permission in writing from CIE Central Bureau at the address below.CIE Central BureauKegelgasse 27A-1030 ViennaAustriaTel.: +43 1 71
4、4 3187 0Fax: +43 1 713 0838 18e-mail: ciecbping.atWeb: www.cie.co.at/cieCIE S 011/E:2003g211 CIE, 2003 All rights reserved IIIFOREWORDStandards produced by the Commission Internationale de lEclairage (CIE) are a concisedocumentation of data defining aspects of light and lighting, for which internati
5、onal harmonyrequires such unique definition. CIE Standards are therefore a primary source ofinternationally accepted and agreed data, which can be taken, essentially unaltered, intouniversal standard systems.This Standard has been prepared by CIE Technical Committee 3-15*) of Division 3(Interior Env
6、ironment and Lighting Design) “Sky luminance models“ and was approved by theNational Committees of the CIE. This present standard replaces CIE S003 - 1996 “Spatialdistribution of daylight - CIE standard overcast sky and clear sky“.TABLE OF CONTENTSFOREWORD IIIINTRODUCTION 11. SCOPE 12. NORMATIVE REF
7、ERENCES 13. LIST OF SYMBOLS 24. SPECIFICATION: THE RELATIVE SKY LUMINANCE DISTRIBUTION 35. SPECIFICATION: STANDARD PARAMETERS 36. SPECIFICATION: THE TRADITIONAL OVERCAST SKY 67. DERIVATION OF THE STANDARD SKY 6ANNEX A (INFORMATIVE): REFERENCES 7*) Chairman of this TC was Y. Uetani (JP), members were
8、: S. Aydinli (DE), A. Joukoff (BE),J. D. Kendrick (AU), R. Kittler (SK), Y. Koga (JP), K. Matsuura (JP), T. Nagata (JP),H. Nakamura (JP), M. Oki (JP), R. Perez (US), P. R. Tregenza (UK), P. Valko (CH).g211 CIE, 2003CIE S 011/E:2003IV g211 CIE, 2003 - All rights reservedCIE S 011/E:2003g211 CIE, 2003
9、 All rights reserved 1SPATIAL DISTRIBUTION OF DAYLIGHT - CIE STANDARD GENERALSKYINTRODUCTIONThe luminance distribution of the sky depends on weather and climate, and it changes duringthe course of a day with the position of the sun. This standard lists a set of luminancedistributions, which model th
10、e sky under a wide range of conditions, from the heavily overcastsky to cloudless weather. It is intended for two purposes:i. to be a universal basis for the classification of measured sky luminance distributionsii. to give a method for calculating sky luminance in daylighting design procedures.The
11、Standard defines relative luminance distributions: the luminance of the sky at anypoint is given as a function of the zenith luminance. For daylighting calculation purposes itmay be used with values of zenith luminance or of horizontal illuminance to obtain absoluteluminance distributions.The Standa
12、rd incorporates both the CIE Standard Clear Sky and the CIE StandardOvercast Sky, which are treated as particular cases of the General Sky. The Overcast Sky isretained as a separate formula because there are many calculation procedures that embodythe mathematical formulation of this particular distr
13、ibution.1. SCOPEThis Standard defines a set of outdoor daylight conditions linking sunlight and skylight fortheoretical and practical purposes.The luminance distributions given have the following characteristics:i. They are symmetrical about the solar meridian and are functions of the angulardistanc
14、e, Zs, between the sun and the zenith.ii. They are defined by smooth continuous functions. Such distributions are typical ofcloudless skies and of those where the cloud cover is homogeneous. They provide anapproximation to skies of broken cloud that is sufficiently accurate for many practicaldayligh
15、t calculation purposes.iii. The relative luminance at any point in the sky depends on the angle, g99, between thatsky element and the sun, and on the angle, Z, between the sky element and thezenith. It is given in terms of two functions: the relative scattering indicatrix, f(g99), andthe luminance g
16、radation between horizon and zenith, g106(Z).2. NORMATIVE REFERENCESThe following standards contain provisions, which through reference in the text, constituteprovisions of this standard. At the time of publication, the editions indicated were valid. Allstandards are subject to revision, and parties
17、 to agreements based on the Standard areencouraged to investigate the possibility of applying the most recent editions of the standardsindicated below. Members of the CIE, IEC and ISO maintain registers of currently validinternational standards.1. CIE 17.4-1987 International Lighting Vocabulary, ILV
18、 (joint publication IEC/CIE).2. ISO 31:1992 Quantities and Units, Part 6: Light and Related Electromagnetic Radiations.CIE S 011/E:20032 g211 CIE, 2003 - All rights reserved3. LIST OF SYMBOLSFor the purposes of this Standard, the following symbols apply:a, b luminance gradation parametersg97 azimuth
19、 of a sky element (clockwise from north) radg97sazimuth of the sun (clockwise from north) radc, d, e scattering indicatrix parametersg99 shortest angular distance between a sky element and the sun radf(g99) scattering indicatrix functiong106(Z) luminance gradation functiong103 angle of elevation of
20、a sky element above the horizon radg103sangle of elevation of the sun above the horizon radLaluminance of a sky element cd/m2 Lzzenith luminance cd/m2 Z angular distance between a sky element and the zenith radZsangular distance between the sun and zenith radFor quantities and units see Normative Re
21、ferences 1 & 2.zenithsunsky elementNorthZZssg103g103sg97g97g99Figure 1. Angles defining the position of the sun and a sky element.g97sg97g103g103Zg99CIE S 011/E:2003g211 CIE, 2003 All rights reserved 34. SPECIFICATION: THE RELATIVE SKY LUMINANCE DISTRIBUTIONThe position of an arbitrary sky element i
22、s defined by its zenith angle, Z, and by the azimuthdifference between the element and the sun, g124g97-g97sg124. If Zsis the zenith angle of the sun, theangular distance between the element and the sun isg40 g41ssscossinsincoscosarccos g97g97g99 g45g215g215g43g215g61 ZZZZ (1)Alternatively, the angl
23、e of elevation, g103, may be used instead of the zenith angle, Z, todefine the position of an element. Theng103g45g112g612Z (2)Similarly the zenith angle of the sun may be obtained from the solar elevation byss2g103g45g112g61Z (3)The ratio of the luminance, La, of an arbitrary sky element to the zen
24、ith luminance, Lz, is)0()()()(szag106g106g99g215g215g61ZfZfLL(4)The luminance gradation function, g106, relates the luminance of a sky element to its zenithangle:horizon the at ,1220 when ,cosexp1)(g61g247g248g246g231g232g230g60g163g247g248g246g231g232g230g215g43g61g112g106g112g106 ZZbaZ(5)The param
25、eters a and b are given in Table 1 for standard sky types.Equation 4 requires the value at the zenith. This isba exp1)0( g215g43g61g106 (6)The function f is a scattering indicatrix which relates the relative luminance of a sky element toits angular distance from the sun:g40g41 g99g99g992cos2expexp1)
26、( g215g43g250g251g249g234g235g233g247g248g246g231g232g230 g112g45g215g43g61 eddcf (7)Its value at the zenith isg40g41s2sscos2expexp1)( ZeddZcZf g215g43g250g251g249g234g235g233g247g248g246g231g232g230 g112g45g215g43g61 (8)5. SPECIFICATION: STANDARD PARAMETERSFor purposes of classification and descrip
27、tion, the parameters a to e in equations 5 - 8 shallbe selected from Table 1. This lists fifteen standard relative luminance distributions which arebased on six groups of a and b values for the gradation function and six groups of c, d and evalues for the indicatrix function. The resulting curves ar
28、e illustrated in Figs. 2 and 3.CIE S 011/E:20034 g211 CIE, 2003 - All rights reservedTable 1. Standard parameters.TypeGrada-tiongroupIndica-trixgroupa b c d e Description of luminance distribution1 I 1 4,0 -0,70 0 -1,0 0CIE Standard Overcast Sky,Steep luminance gradation towardszenith, azimuthal uni
29、formity2 I 2 4,0 -0,70 2 -1,5 0,15Overcast, with steep luminancegradation and slight brighteningtowards the sun3 II 1 1,1 -0,8 0 -1,0 0Overcast, moderately graded withazimuthal uniformity4 II 2 1,1 -0,8 2 -1,5 0,15Overcast, moderately graded andslight brightening towards the sun5 III 1 0 -1,0 0 -1,0
30、 0 Sky of uniform luminance6 III 2 0 -1,0 2 -1,5 0,15Partly cloudy sky, no gradationtowards zenith, slight brighteningtowards the sun7 III 3 0 -1,0 5 -2,5 0,30Partly cloudy sky, no gradationtowards zenith, brighter circumsolarregion8 III 4 0 -1,0 10 -3,0 0,45Partly cloudy sky, no gradationtowards ze
31、nith, distinct solar corona9 IV 2 -1,0 -0,55 2 -1,5 0,15 Partly cloudy, with the obscured sun10 IV 3 -1,0 -0,55 5 -2,5 0,30Partly cloudy, with brightercircumsolar region11 IV 4 -1,0 -0,55 10 -3,0 0,45White-blue sky with distinct solarcorona12 V 4 -1,0 -0,32 10 -3,0 0,45CIE Standard Clear Sky,low lum
32、inance turbidity13 V 5 -1,0 -0,32 16 -3,0 0,30CIE Standard Clear Sky,polluted atmosphere14 VI 5 -1,0 -0,15 16 -3,0 0,30Cloudless turbid sky with broadsolar corona15 VI 6 -1,0 -0,15 24 -2,8 0,15White-blue turbid sky with broadsolar coronaCIE S 011/E:2003g211 CIE, 2003 All rights reserved 50,20,512580
33、 30 60 90relativegradationf()/f(0)Zzenith angle in degreesZVIVIVIIIIIIFigure 2. Standard gradation function groups.12430 60 90 120 150 1800Scattering angle in degreesg99g32151020Relativeindicatrixf()g9956 30.8Relativegradation g106(Z)/g106(0)Scattering angle g99 in degreesFigure 3. Standard indicatr
34、ix function groups.Zenith angle Z in degreesRelativeindicatrixf(g99)0,8CIE S 011/E:20036 g211 CIE, 2003 - All rights reserved6. SPECIFICATION: THE TRADITIONAL OVERCAST SKYThe Standard General Sky integrates the traditional overcast sky formula as the 16thsky* thatmay be used as an alternate to Sky T
35、ype 1 when only overcast skies are to be modelled. Thisluminance distribution should be expressed by the ratio of the luminance of a sky element,Loc(g103), to the zenith luminance, Lzoc:g40g413sin21zococg103g103 g215g43g61LL(9)where g103 is the angle of elevation of the sky element above the horizon
36、.The difference between Sky Types 1 and 16 is shown on Fig. 4.0.00.10.20.30.40.50.60.70.80.91.00 102030405060708090Angular distance between a sky element and the zenith degRelative Luminance-30%-20%-10%0%10%20%30%Relative Diiference %CIE General Sky: Sky Type 1Traditional Overcast Sky: Sky Type 16Re
37、lative Difference %Figure 4. Difference between Sky Types 1 and 16.7. DERIVATION OF THE STANDARD SKYThe CIE Standard Overcast Sky and the CIE Standard Clear Sky were developed in a seriesof publications between 1955 and 1994 1-4.The CIE Standard General Sky is a generalisation of the CIE Clear Sky f
38、ormula 5. Ithas been shown to be a good model of skies with smoothly varying luminous distributionsoccurring in various climatic conditions 7,8. Formulae of this type have also been shown toprovide a good approximation to skies of broken cloud in maritime climates 9,11. It has alsobeen shown that ap
39、proximately four types of the General Sky can give a goodcharacterisation of the exterior daylight conditions, although the particular sky types may differbetween climates 11.Absolute values of sky luminance vary with solar elevation, and therefore withlatitude. Empirical equations for zenith lumina
40、nce and horizontal illuminance have beenpublished for various climates 6,10,12,13.* Same as CIE Standard Overcast Sky of CIE S003/E-1996.CIE S 011/E:2003g211 CIE, 2003 All rights reserved 7ANNEX A (INFORMATIVE): REFERENCES1. Compte Rendu CIE 13 Session 1955. Natural Daylight. Official Recommendation
41、, 2, part3.2, II-IV & 35-37 (1955).2. CIE 22-1973. Standardisation of luminance distribution on clear skies.3. CIE 110-1994. Spatial distribution of daylight g45 Luminance distribution of variousreference skies.4. CIE S 003/E-1996. Spatial Distribution of Daylight g45 CIE Standard Overcast Sky andCl
42、ear Sky5. KITTLER, R., PEREZ, R. and DARULA S. A new generation of sky standards. Proc. LuxEuropa Conf. 359-373 (1997).6. KITTLER, R. and DARULA, S. Parameterisation problems of the very bright cloudy skyconditions. Solar Energy, 62 (2), 93-100 (1998).7. PEREZ, R., SEALS, R., and MICHALSKY, J. All-W
43、eather Model for Sky LuminanceDistribution - Preliminary Configuration and Validation. Solar Energy, 50 (3), 235-245(1993).8. KITTLER, R., PEREZ, R. and DARULA, S. A set of standard skies characterising daylightconditions for computer and energy conscious design. Final Report of the U.S.-SlovakGrant
44、 Project US-SK 92 052. Without appendices published by Polygrafia, Bratislava.(1998).9. MATSUZAWA, T., NAKAMURA, H., IGAWA, N. KOGA, Y, GOTO, K. and KOJO, S. Skyluminance distribution between two CIE Standard Skies (Part 1), Arrangement of the skyluminance distribution data measured. Proc. Lux Pacif
45、ica 97, Nagoya, Japan, E.7 E.12(1997).10. IGAWA, N., NAKAMURA, H., MATSUZAWA, T., KOGA,Y., GOTO, K. and KOJO, S. Skyluminance distribution between two CIE Standard Skies (Part 2). Numerical equation forrelative sky luminance distributions. Proc. Lux Pacifica 97, Nagoya, Japan, E.13 E.18(1997).11. TR
46、EGENZA, P. R. Standard skies for maritime climates. Lighting Res. & Technol, 31 (3),97-106 (1999).12. KITTLER, R., PEREZ, R. and DARULA, S. Universal models of reference daylightconditions based on new sky standards. In Proc.24thSession of the CIE. CIE 133 - 1999,Vol.1 Part 1, 243-247.13. IGAWA, N.,
47、 NAKAMURA, H. and MATSUURA, K. Sky luminance distribution model forsimulation of daylit environment. Proc. Building Simulation 99, Kyoto, 969-975 (1999).Copies of CIE Publications are available from the National Committees of most CIE membercountries. Purchasers in other countries may obtain them from the CIE Central Bureau,Kegelgasse 27, A-1030 Wien, Austria.CIE S 011/E:20038 g211 CIE, 2003 - All rights reservedCIE Central BureauKegelgasse 27A-1030 ViennaAustriaTel.: +43 1 714 3187 0Fax: +43 1 713 0838 18e-mail: ciecbping.atWWW: http:/www.cie.co.at/cie/
