A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass
Autor(a) principal: | |
---|---|
Data de Publicação: | 2007 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1007/s00704-006-0283-z http://hdl.handle.net/11449/231048 |
Resumo: | This work describes a new algorithm to characterize sky condition in intervals of 5min using four categories of sun exposition: apparent sun with cloud reflection effects; apparent sun without cloud effects; sun partially concealed by clouds; and sun totally concealed by clouds. The algorithm can also be applied to estimate hourly and daily sky condition in terms of the traditional three categories: clear, partially cloudy and cloudy day. It identifies sky conditions within a confidence interval of 95% by minimizing local climate and measurement effects. This is accomplished by using a logistic cumulative probability function to characterize clear sky and Weibull cumulative probability function to represent cloudy sky. Both probability functions are derived from frequency distributions of clearness index, based on 5 minutes-averaged values of global solar irradiance observed at the surface during a period of 6 years in Botucatu, Southeastern of Brazil. The relative sunshine estimated from the new algorithm is statistically comparable to the one derived from Campbell-Stocks sunshine recorder for both daily and monthly values. The new method indicates that the highest frequency of clear sky days occurs in Botucatu during winter (66%) and the lowest during the summer (38%). Partially cloudy condition is the dominant feature during all months of the year. © Springer-Verlag 2007. |
id |
UNSP_46b27972fc7a007f20effafeadf418dd |
---|---|
oai_identifier_str |
oai:repositorio.unesp.br:11449/231048 |
network_acronym_str |
UNSP |
network_name_str |
Repositório Institucional da UNESP |
repository_id_str |
2946 |
spelling |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air massThis work describes a new algorithm to characterize sky condition in intervals of 5min using four categories of sun exposition: apparent sun with cloud reflection effects; apparent sun without cloud effects; sun partially concealed by clouds; and sun totally concealed by clouds. The algorithm can also be applied to estimate hourly and daily sky condition in terms of the traditional three categories: clear, partially cloudy and cloudy day. It identifies sky conditions within a confidence interval of 95% by minimizing local climate and measurement effects. This is accomplished by using a logistic cumulative probability function to characterize clear sky and Weibull cumulative probability function to represent cloudy sky. Both probability functions are derived from frequency distributions of clearness index, based on 5 minutes-averaged values of global solar irradiance observed at the surface during a period of 6 years in Botucatu, Southeastern of Brazil. The relative sunshine estimated from the new algorithm is statistically comparable to the one derived from Campbell-Stocks sunshine recorder for both daily and monthly values. The new method indicates that the highest frequency of clear sky days occurs in Botucatu during winter (66%) and the lowest during the summer (38%). Partially cloudy condition is the dominant feature during all months of the year. © Springer-Verlag 2007.Department of Geography Federal University of Goiás Campus of Jataí, Jataí, GoiásDepartment of Natural Resources School of Agronomic Science University of State of São Paulo, Botucatu, São PauloDepartment of Atmospheric Sciences Institute of Astronomy Geophysics and Atmospheric Sciences University of São Paulo, São PauloUniversidade Federal de Goiás (UFG)University of State of São PauloUniversidade de São Paulo (USP)Assunção, Hildeu F.Escobedo, João F.Oliveira, Amauri P.2022-04-29T08:43:21Z2022-04-29T08:43:21Z2007-01-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article235-248http://dx.doi.org/10.1007/s00704-006-0283-zTheoretical and Applied Climatology, v. 90, n. 3-4, p. 235-248, 2007.1434-44830177-798Xhttp://hdl.handle.net/11449/23104810.1007/s00704-006-0283-z2-s2.0-35448994739Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengTheoretical and Applied Climatologyinfo:eu-repo/semantics/openAccess2024-04-30T19:29:56Zoai:repositorio.unesp.br:11449/231048Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T23:55:58.208141Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass |
title |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass |
spellingShingle |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass Assunção, Hildeu F. |
title_short |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass |
title_full |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass |
title_fullStr |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass |
title_full_unstemmed |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass |
title_sort |
A new algorithm to estimate sky condition based on 5 minutes-averaged values of clearness index and relative optical air mass |
author |
Assunção, Hildeu F. |
author_facet |
Assunção, Hildeu F. Escobedo, João F. Oliveira, Amauri P. |
author_role |
author |
author2 |
Escobedo, João F. Oliveira, Amauri P. |
author2_role |
author author |
dc.contributor.none.fl_str_mv |
Universidade Federal de Goiás (UFG) University of State of São Paulo Universidade de São Paulo (USP) |
dc.contributor.author.fl_str_mv |
Assunção, Hildeu F. Escobedo, João F. Oliveira, Amauri P. |
description |
This work describes a new algorithm to characterize sky condition in intervals of 5min using four categories of sun exposition: apparent sun with cloud reflection effects; apparent sun without cloud effects; sun partially concealed by clouds; and sun totally concealed by clouds. The algorithm can also be applied to estimate hourly and daily sky condition in terms of the traditional three categories: clear, partially cloudy and cloudy day. It identifies sky conditions within a confidence interval of 95% by minimizing local climate and measurement effects. This is accomplished by using a logistic cumulative probability function to characterize clear sky and Weibull cumulative probability function to represent cloudy sky. Both probability functions are derived from frequency distributions of clearness index, based on 5 minutes-averaged values of global solar irradiance observed at the surface during a period of 6 years in Botucatu, Southeastern of Brazil. The relative sunshine estimated from the new algorithm is statistically comparable to the one derived from Campbell-Stocks sunshine recorder for both daily and monthly values. The new method indicates that the highest frequency of clear sky days occurs in Botucatu during winter (66%) and the lowest during the summer (38%). Partially cloudy condition is the dominant feature during all months of the year. © Springer-Verlag 2007. |
publishDate |
2007 |
dc.date.none.fl_str_mv |
2007-01-01 2022-04-29T08:43:21Z 2022-04-29T08:43:21Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1007/s00704-006-0283-z Theoretical and Applied Climatology, v. 90, n. 3-4, p. 235-248, 2007. 1434-4483 0177-798X http://hdl.handle.net/11449/231048 10.1007/s00704-006-0283-z 2-s2.0-35448994739 |
url |
http://dx.doi.org/10.1007/s00704-006-0283-z http://hdl.handle.net/11449/231048 |
identifier_str_mv |
Theoretical and Applied Climatology, v. 90, n. 3-4, p. 235-248, 2007. 1434-4483 0177-798X 10.1007/s00704-006-0283-z 2-s2.0-35448994739 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Theoretical and Applied Climatology |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
235-248 |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1808129565209395200 |