Data/hora: 20/06/2024 22:18:51

Biblioteca(s): 	Embrapa Cerrados.	
Data corrente: 	25/03/2002	
Data da última atualização: 	25/03/2002	
Autoria: 	POST, D. F.; FIMBRES, A.; MATTHIAS, A. D.; SANO, E. E.; ACCIOLY, L.; BATCHILY, A. K.; FERREIRA, L. G.	
Título: 	Prediciting soil albedo from soil color and spectral reflectance data.	
Ano de publicação: 	2000	
Fonte/Imprenta: 	Soil Science Society of America Journal, Madison, v. 64, n. 3, p. 1027-1034, 2000.	
Idioma: 	Inglês	
Conteúdo: 	The albedo of earthsurface features, such as soil, is na important component of models that define land-surface meteorological processes. If land surfaces have no vegetative cover, soil properties determine the amount of solar radiation absorbed or reflected. We evaluated the influence of two soil properties, soil color and soil moisture, on soil albedo. Two soil moisture conditions were studied, air dry and wet, defined as the condition when the water films are absorbed by the soil and no water glistens on the soil surface. The albedos for 26 U.S. soils were measured with na Eppley pyranometer, which integrates radiant energy in wavelengths between 0.3 to 2.8 um. Soil colors were measured with a Minolta Chroma Meter and spectral reflectance curves from 0.45 to 0.9 um (measured in 0.1-um increments) were determined with a multispectral radiometer. All measurements were made on maior 2-mm smooth soil surfaces, and the dry and wet data were combined for statistical analyses. Soil albedos were significantly correlated with Munsell soil color value (r2=0.93), blue (r2=0.82), green (r2=0.90), red (r2=0.93), near infrared (NIR), (r2= 0.95), and sum of the four bands (r2= 0.94); however, the slopes and intercepts for these relationships were different. The 52 spectral curves yielded nine cluster groups, which mostly related to the Munsell soil color value and soil albedo soil characteristics. The 0.3-to 2.8-um albedos of smoothed soils can be accurately estimated using the regression relationship: soil albedo (0.3-2.8um) = 0.069 (color value) - 0.114. Using the regression equations presented here, spectral reflectance data in selected visible and NIR bands can also be used to predict albedo.	
Palavras-Chave: 	Refletancia.	
Thesagro: 	Solo.	
Thesaurus Nal: 	reflectance; soil.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Cerrados (CPAC)	
Exemplares: 	CPAC - (20959-1) - UPC - SP - -- - CRI5781 -  - CRI5781 - DIS