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Registro Completo |
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Biblioteca(s): |
Embrapa Agricultura Digital. |
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Data corrente: |
28/04/2009 |
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Data da última atualização: |
01/12/2010 |
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Autoria: |
GARCIA, B. I. L.; SENTELHAS, P. C.; TAPIA, L.; SPAROVEK, G. |
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Afiliação: |
BEATRIZ IBET LOZADA GARCIA, INIA, Venezuela; PAULO CESAR SENTELHAS, ESALQ/USP; LUCIANO TAPIA, CIAGRI/USP; GERD SPAROVEK, ESALQ/USP. |
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Título: |
Filling in missing rainfall data in the Andes region of Venezuela, based on a cluster analysis approach. |
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Ano de publicação: |
2006 |
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Fonte/Imprenta: |
Revista Brasileira de Agrometeorologia, Piracicaba, v. 14, n. 2, p. 225-233, 2006. |
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Idioma: |
Inglês |
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Conteúdo: |
Several agrometeorological studies require daily rainfall, mainly those wich have as objective to model or simulate water budget, crop development and yield, and occurrence of crop pests and diseases. However, the presence of missing data is a problem that normally occurs, which limits these studies. The origin of this problem varies, but they are more related to improperly devices functioning or lack of technical officers to make observations. Such problems are common in the different institutions which control weather-stations networks in Venezuela. Simple and feasible alternatives to improve the quality of rainfall database are required. We established the hypothesis that daily rainfall data from a weather station can be used to fill in missing data from another surrounding weather station. Data used to test our hypothesis were obtained from 106 weather stations in the Andes region, Venezuela, considering a period of 31 years (1967-1997). The original rainfall database presented 17.3% of missing data (207,534 days). Using a cluster analysis (Ward's method, with Euclidean distance), the proposed method, named as Closest Station, reduced the percentage of missing data to 2.5% (29,495 days). The performance of our proposed method was evaluated by mean absolute error (MAE), which ranged from 1.7 to 4.0 mm day-1, and by Willmott agreement index (d), which was 0.57 for daily basis and 0.83 for monthly basis. The contingency analysis showed that our proposed method overestimated rainfall events for daily data, which resulted in a small fraction of correct estimates (FC = 0.48) and a larger false alarm ratio (FAR = 0.53), limiting their use. For the other time scales, from 7 to 30 days, FC was greater than 0.88 and FAR smaller than 0.07, which allow the use of this technique for several purposes in agrometeorological studies. MenosSeveral agrometeorological studies require daily rainfall, mainly those wich have as objective to model or simulate water budget, crop development and yield, and occurrence of crop pests and diseases. However, the presence of missing data is a problem that normally occurs, which limits these studies. The origin of this problem varies, but they are more related to improperly devices functioning or lack of technical officers to make observations. Such problems are common in the different institutions which control weather-stations networks in Venezuela. Simple and feasible alternatives to improve the quality of rainfall database are required. We established the hypothesis that daily rainfall data from a weather station can be used to fill in missing data from another surrounding weather station. Data used to test our hypothesis were obtained from 106 weather stations in the Andes region, Venezuela, considering a period of 31 years (1967-1997). The original rainfall database presented 17.3% of missing data (207,534 days). Using a cluster analysis (Ward's method, with Euclidean distance), the proposed method, named as Closest Station, reduced the percentage of missing data to 2.5% (29,495 days). The performance of our proposed method was evaluated by mean absolute error (MAE), which ranged from 1.7 to 4.0 mm day-1, and by Willmott agreement index (d), which was 0.57 for daily basis and 0.83 for monthly basis. The contingency analysis showed that our proposed method overestimate... Mostrar Tudo |
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Palavras-Chave: |
Método Estação mais próxima; Precipitação; Séries históricas. |
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Thesagro: |
Chuva; Climatologia. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02520naa a2200217 a 4500
001 1032142
005 2010-12-01
008 2006 bl uuuu u00u1 u #d
100 1 $aGARCIA, B. I. L.
245 $aFilling in missing rainfall data in the Andes region of Venezuela, based on a cluster analysis approach.
260 $c2006
520 $aSeveral agrometeorological studies require daily rainfall, mainly those wich have as objective to model or simulate water budget, crop development and yield, and occurrence of crop pests and diseases. However, the presence of missing data is a problem that normally occurs, which limits these studies. The origin of this problem varies, but they are more related to improperly devices functioning or lack of technical officers to make observations. Such problems are common in the different institutions which control weather-stations networks in Venezuela. Simple and feasible alternatives to improve the quality of rainfall database are required. We established the hypothesis that daily rainfall data from a weather station can be used to fill in missing data from another surrounding weather station. Data used to test our hypothesis were obtained from 106 weather stations in the Andes region, Venezuela, considering a period of 31 years (1967-1997). The original rainfall database presented 17.3% of missing data (207,534 days). Using a cluster analysis (Ward's method, with Euclidean distance), the proposed method, named as Closest Station, reduced the percentage of missing data to 2.5% (29,495 days). The performance of our proposed method was evaluated by mean absolute error (MAE), which ranged from 1.7 to 4.0 mm day-1, and by Willmott agreement index (d), which was 0.57 for daily basis and 0.83 for monthly basis. The contingency analysis showed that our proposed method overestimated rainfall events for daily data, which resulted in a small fraction of correct estimates (FC = 0.48) and a larger false alarm ratio (FAR = 0.53), limiting their use. For the other time scales, from 7 to 30 days, FC was greater than 0.88 and FAR smaller than 0.07, which allow the use of this technique for several purposes in agrometeorological studies.
650 $aChuva
650 $aClimatologia
653 $aMétodo Estação mais próxima
653 $aPrecipitação
653 $aSéries históricas
700 1 $aSENTELHAS, P. C.
700 1 $aTAPIA, L.
700 1 $aSPAROVEK, G.
773 $tRevista Brasileira de Agrometeorologia, Piracicaba$gv. 14, n. 2, p. 225-233, 2006.
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Registro original: |
Embrapa Agricultura Digital (CNPTIA) |
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Registro Completo
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Biblioteca(s): |
Embrapa Algodão. |
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Data corrente: |
10/11/2011 |
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Data da última atualização: |
17/11/2011 |
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Autoria: |
SIQUERI, F. V.; CARRETERO, D. M.; OLIVEIRA, W. F. de; ALVES, F. L. C.; KOCH, C. V.; SANTOS, P. F. dos. |
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Afiliação: |
FABIANO VICTOR SIQUERI; DIEGO MARTINS CARRETERO; WELTON FRANCO DE OLIVEIRA; LINEU CRISTIANO FERREIRA; CHARLES VANDEREI KOCH; PRISCILA FERREIRA DOS SANTOS. |
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Título: |
Interação entre o número de aplicações de fungicidas e 5 diferentes cultivares de algodão no controle da mancha de Ramularia. |
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Ano de publicação: |
2011 |
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Fonte/Imprenta: |
In: CONGRESSO BRASILEIRO DE ALGODÃO, 8.; COTTON EXPO, 1., 2011, São Paulo. Evolução da cadeia para construção de um setor forte: Anais. Campina Grande, PB: Embrapa Algodão, 2011. |
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Páginas: |
p.415-422 |
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Idioma: |
Português |
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Palavras-Chave: |
FUNGICIDAS; RAMULARIA AREOLA; RESISTÊNCIA A DOENÇA; VARIEDADES. |
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Categoria do assunto: |
-- |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/46153/1/FIP-006Poster.114.pdf
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Marc: |
LEADER 00838naa a2200229 a 4500
001 1905648
005 2011-11-17
008 2011 bl uuuu u00u1 u #d
100 1 $aSIQUERI, F. V.
245 $aInteração entre o número de aplicações de fungicidas e 5 diferentes cultivares de algodão no controle da mancha de Ramularia.
260 $c2011
300 $ap.415-422
653 $aFUNGICIDAS
653 $aRAMULARIA AREOLA
653 $aRESISTÊNCIA A DOENÇA
653 $aVARIEDADES
700 1 $aCARRETERO, D. M.
700 1 $aOLIVEIRA, W. F. de
700 1 $aALVES, F. L. C.
700 1 $aKOCH, C. V.
700 1 $aSANTOS, P. F. dos
773 $tIn: CONGRESSO BRASILEIRO DE ALGODÃO, 8.; COTTON EXPO, 1., 2011, São Paulo. Evolução da cadeia para construção de um setor forte: Anais. Campina Grande, PB: Embrapa Algodão, 2011.
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Embrapa Algodão (CNPA) |
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