1993 Fiscal Year Final Research Report Summary
CLOUDS AND CLOUD AMOUNT AS BASIC DATA FOR THE THERMAL AND LUMINOUS ENVIRONMENT
| Project/Area Number |
03452227
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
建築環境・環境工学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
NAKAMURA Hiroshi KYUSHU UNIV.DEPT.OF ARCHITECTURE, PROFESSOR, 工学部, 教授 (10024209)
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| Co-Investigator(Kenkyū-buntansha) |
KOGA Yasuko KYUSHU UNIV.DEPT.OF ARCHITECTURE, RESEARCH ASSOCIATE, 工学部, 助手 (60225399)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Cloud amount / Automatic measurement of cloud amount / Color of blue sky / Color of cloud |
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| Research Abstract |
The following results suggest possibility of developing automatic long-term continuous measurement instrument of cloud amount. (1)Measurement of cloud amount and color of the sky Sky luminance and chromaticity of light from the sky were measured using a color luminance photometer. Besides, photographs with a fisheye lens and sletches of the sky were made. Visual judgment of sky conditions at each measurement point and visual observation of cloud amount were also made. (2)Determination of sky conditions by color temperature Color temperature of blue sky is higher than 10000K.Color temperatures of blue sky and cloud are mixed in lower than 10000K.Color temperature of cloud ranges from about 3000K about 8500K, and occurs frequently in the range of 5500K.It seems possible to judge sky conditions by color temperature at a large angular distance from the sun. (3)Numerical formula of color temperature of blue sky Color temperature of blue sky was expressed numerically with solar altitude, an elevation of the sky element, angular distance between the sky element and the sun, and atmospheric transmittance. (4)Regression equations on color temperature for the boundary between blue sky and cloud It si difficult to judge sky conditions only by color temperature at the low elevation and in the vicinity of the sun. Regression equations were obtained on color temperature for the boundary between blue sky and cloud in relation to each of solar altitude, an elevation of the sky element and angular distance between the sky element and the sun. (5)Comparison between the abserved cloud amount and the estimated cloud amount Cloud amount was estimated with the data re-sorted into the groups of blue sky and cloud according to the boundary conditions in (4). Cloud amount was estimated in another way by integrating the zones visually-judged as cloud. Comparison between the observed cloud amount and two kinds of the estimated cloud amount resulted in about 75% agreement allowing the differe
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