Title :
Combined visible-near infrared and multi-band thermal infrared data for discrimination of vegetated and bare surfaces
Author :
French, Andrew N. ; Schmugge, Thomas J. ; Kustas, William P.
Author_Institution :
USDA/ARS Hydrology Lab., Beltsville, MD, USA
Abstract :
Land classification data sets that are required for energy flux modeling of landscape scale remotely sensed data are highly reliant upon vegetation indices for estimating fractional vegetation cover. The visible-near infrared band based index, NDVI, was found inadequate in a previous study of rangelands at El Reno, Oklahoma (SGP97). Bare soil and senescent vegetation, surfaces with quite different energy transport properties, could sometimes not be distinguished. A practical, remote sensor based remedy to this problem was developed from multi-band thermal infrared data, which was used to create an image of spectral emissivity contrast. Vegetative cover, whether green or brown, showed low emissivity contrast, while bare soil surfaces showed high emissivity contrast. When emissivity contrast data were combined with NDVI data, harvested winter wheat could be discriminated from plowed fields, which improved two-source model estimates of surface heat flux. This approach will have wider application when multi-spectral thermal infrared data becomes available from the ASTER instrument
Keywords :
image classification; soil; vegetation mapping; ASTER instrument; NDVI data; bare soil; bare surfaces; emissivity contrast; energy flux modeling; energy transport; harvested winter wheat; land classification data sets; landscape scale remotely sensed data; multi-band thermal infrared data; multi-spectral thermal infrared data; plowed fields; remote sensor; senescent vegetation; spectral emissivity contrast; surface heat flux; two-source model estimates; vegetated and bare surfaces; vegetative cover; visible-near infrared data; Infrared spectra; Instruments; Land surface; Land surface temperature; Meteorology; Remote monitoring; Remote sensing; Soil measurements; Temperature sensors; Vegetation mapping;
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2000. Proceedings. IGARSS 2000. IEEE 2000 International
Conference_Location :
Honolulu, HI
Print_ISBN :
0-7803-6359-0
DOI :
10.1109/IGARSS.2000.859597