NOAA/NASA Pathfinder NDVI

Two land surface data sets from the NOAA/NASA AVHRR (Advanced Very High Resolution Radiometer) Pathfinder Project on the NOAA/TIROS operational meteorological satellites are available on EOS-WEBSTER (http://eos-earthdata.sr.unh.edu/). Both data sets are derived from the Pathfinder Composite Data Set which in turn is derived from the Pathfinder Daily Data Set. The Pathfinder Composite Data Set is generated by comparing the NDVI (Normalized Difference Vegetation Index) values for each 8 km bin from 10 consecutive Daily Data Sets. The pixel with the highest NDVI for the 10 days is chosen as the date for inclusion in the composite. This compositing process is effective for removing most of the clouds and atmospheric contaminants, thus providing as close to a cloud free field in each of the data layers as is possible [Holben (1986)International Journal of Remote Sensing, 7:1417-1434]. There are three composites per month for each year of data.

The first composite of each month is for days 1 to 10, the second composite is for days 11 to 20, and the third composite is for the remaining days.

The Amazon 0.1 degree data set on EOS-WEBSTER is a monthly maximum recomposite value of NDVI data from the Pathfinder Composite Data Set reprojected to 0.1 degree for the Amazon region. The temporal scale is from August 1981 through July 1994.

The Global 0.5 degree data set on EOS-WEBSTER is a monthly maximum recomposite value of NDVI data from the Pathfinder Composite Data Set reprojected to 0.5 degree for terrestrial and climate modeling applications. The data span from August 1981 through July 1994.

For a full discussion of the NOAA/NASA Pathfinder AVHRR Land Data Sets please consult the Goddard DAAC Pathfinder Data Guide or the AVHRR User's Guide (available in PDF format).