AVHRR temporal analysis of a savanna site in Brazil

Autor:	H. Franca, Alberto Setzer
Rok vydání:	1998
Předmět:	Phenology Advanced very-high-resolution radiometer Thematic Mapper medicine General Earth and Planetary Sciences Environmental science Radiometry Satellite Enhanced vegetation index medicine.symptom Vegetation (pathology) Normalized Difference Vegetation Index Remote sensing
Zdroj:	International Journal of Remote Sensing. 19:3127-3140
ISSN:	1366-5901 0143-1161
DOI:	10.1080/014311698214226
Popis:	This work investigated the temporal monitoring of savanna ('cerrado') vegetation phenology in the Emas National Park of Brazil utilizing 1.1 km full resolution daily images of the Advanced Very High Resolution Radiometer (AVHRR) on-board the NOAA-11 satellite. For a period of 18 months studied in 1992-93, only 26 images had useful data. Digital analysis of individual images concentrated on five sub-areas of up to 30 km2 each. Channels used were 1 (0.6-0.7 mu m), 2 (0.7-1.1 mu m) and 3 (3.5-3.9 mu m), as well as the Vegetation Index (NDVI) which combines channels 1 and 2. A high resolution Thematic Mapper (TM) Landsat image and field work provided ground data to identify the vegetation types. Channel 3 and NDVI showed the strongest temporal response to phenological changes of the vegetation, while channels 1 and 2 presented high dependence on the off-nadir scan angle. The results indicated large variations in the daily AVHRR signal of channels 1 and 2 for the same area, regardless of vegetation changes. Re...
Databáze:	OpenAIRE
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