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A Method for Sky-Condition Classification from Ground-Based Solar Radiation Measurements

Identification of clouds from satellite images is now a routine task. Observation of clouds from the ground, however, is still needed to acquire a complete description of cloud conditions. Among the standard meteorologicalvariables, solar radiation is the most affected by cloud cover. In this note, a method for using global and diffuse solar radiation data to classify sky conditions into several classes is suggested. A classical maximum-likelihood method is applied for clustering data. The method is applied to a series of four years of solar radiation data and human cloud observations at a site in Catalonia, Spain. With these data, the accuracy of the solar radiation method as compared with human observations is 45% when nine classes of sky conditions are to be distinguished, and it grows significantly to almost 60% when samples are classified in only five different classes. Most errors are explained by limitations in the database; therefore, further work is under way with a more suitable database

© Journal of Applied Meteorology and Climatology, 2001, vol. 40, núm. 12, p. 2193-2199

American Meteorological Society

Author: Calbó Angrill, Josep
González Gutiérrez, Josep Abel
Pagès, David
Date: 2001
Abstract: Identification of clouds from satellite images is now a routine task. Observation of clouds from the ground, however, is still needed to acquire a complete description of cloud conditions. Among the standard meteorologicalvariables, solar radiation is the most affected by cloud cover. In this note, a method for using global and diffuse solar radiation data to classify sky conditions into several classes is suggested. A classical maximum-likelihood method is applied for clustering data. The method is applied to a series of four years of solar radiation data and human cloud observations at a site in Catalonia, Spain. With these data, the accuracy of the solar radiation method as compared with human observations is 45% when nine classes of sky conditions are to be distinguished, and it grows significantly to almost 60% when samples are classified in only five different classes. Most errors are explained by limitations in the database; therefore, further work is under way with a more suitable database
Format: application/pdf
ISSN: 1558-8432 (versió paper)
1558-8424 (versió electrònica)
Document access: http://hdl.handle.net/10256/7693
Language: eng
Publisher: American Meteorological Society
Collection: Reproducció digital del document publicat a: http://dx.doi.org/10.1175/1520-0450(2001)040<2193:AMFSCC>2.0.CO;2
Articles publicats (D-F)
Is part of: © Journal of Applied Meteorology and Climatology, 2001, vol. 40, núm. 12, p. 2193-2199
Rights: Tots els drets reservats
Subject: Radiació solar
Núvols
Clouds
Meteorologia -- Observacions
Meteorology -- Observations
Sun -- Radiation
Title: A Method for Sky-Condition Classification from Ground-Based Solar Radiation Measurements
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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