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Modeling sky luminescence using satellite data to classify sky conditions
journal contribution
posted on 2023-05-16, 23:00 authored by Janjai, S, Masiri, IO, Manuel NunezManuel Nunez, Laksanaboonsong, JA model for calculating sky luminance is presented. The earth–atmospheric reflectivity obtained from satellite data was used to classify sky conditions. The proposed sky luminance at a specific point in the sky hemisphere is a product of two functions, namely F1 and F2. For any point in a sky hemisphere, F1 varies with the sky zenith of the considered point (Z) and F2 is a function of the angular distance between the considered point and the sun (÷). The model uses simultaneous measurements of sky luminance and GMS-5 satellite observation, both taken at Nakhon Pathom, Thailand (13.70°N, 103.10°E), during November 2002 to May 2003. Both F1 and F2 are derived as polynomial functions of ÷, Z and the solar zenith angle (Zs) for each sky condition. The classification of the sky condition is based on the satellite-derived earth–atmospheric reflectivity. This sky luminance model was validated against independent measurements from the Asia Institute of Technology (AIT) (14.08°N, 100.62°E). The root mean square difference (RMSD) between the relative sky luminance calculated from the model and that obtained from the measurement is 0.133.
History
Publication title
Building and EnvironmentVolume
43Issue
12Pagination
2059-2073ISSN
0360-1323Department/School
School of Geography, Planning and Spatial SciencesPublisher
PergamonPlace of publication
United KingdomRepository Status
- Restricted