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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, J
A 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 Environment

Volume

43

Issue

12

Pagination

2059-2073

ISSN

0360-1323

Department/School

School of Geography, Planning and Spatial Sciences

Publisher

Pergamon

Place of publication

United Kingdom

Repository Status

  • Restricted

Socio-economic Objectives

Air quality, atmosphere and weather not elsewhere classified

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