Map Information: This image portrays the maximum normalized difference vegetation index (NDVI), north of treeline, during maximum green up. The image combines data from 1993 and 1995, which were relatively warm years with minimal snow and cloud cover. NDVI is a measure of vegetation greenness. The index is a ratio of the reflectance in the near infrared (NIR:725-1100 nm) band and the visible red (R:580-680 nm)band, calculated as (NDVI = (NIR-R)/(NIR+R). Reflectance values were obtained from AVHRR imagery. The image was produced for the Circumpolar Arctic Vegetation Mapping Project (CAVM). Funding was provided by the U.S. National Science Foundation, grant number OPP-9732-076.

AVHRR data were obtained from the USGS, EROS Alaska Field Office as biweekly composite images. The circumpolar map was produced by selecting the pixels that had the maximum reflectance during the period of 11 July through 31 August for the years of 1993 and 1995.

Contact Information: NEAML

Related Links: Circumpolar Arctic Vegetation Mapping Project (CAVM)