Smoke effects on NDVI determination of savannah vegetation types

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data collected on 25 and 27 August and 1 September 1995, in central Brazil, were used to describe smoke effects on Normalized Difference Vegetation Index (NDVI) determination of savannah vegetation types. Image-derived empirical relationships were used to predict the response of the red band (sensitive to smoke) from the shortwave infrared (SWIR) bands (insensitive to smoke), so as to minimize smoke effects on NDVI. Results showed that smoke effects were target dependent and produced NDVI differences up to 0.35 between the three dates for dense vegetation covers such as savannah woodland and riparian forest. Although this approach did not consider the smoke influence on the near-infrared (NIR) interval, the small SWIR-derived NDVI differences observed between the dates for a given land cover, under distinct smoke conditions, indicated its applicability in the Brazilian cerrado.