Mapping the circumpolar taiga-tundra ecotone with MODIS tree cover data
Paul
M
Montesano, Sigma Space, NASA GSFC, Code 614.4, paul.m.montesano@nasaq.gov
Jon
Ranson, NASA GSFC, Code 614.4, jon.ranson@nasa.gov
(Presenting)
Ross
F
Nelson, NASA GSFC, Code 614.4, ross.f.nelson@nasa.gov
The circumpolar taiga-tundra transition zone was delineated using an image segmentation based mapping approach with multi-annual MODIS Vegetation Continuous Fields (VCF) tree cover data. Circumpolar tree cover was estimated by averaging MODIS VCF data from 2000 through 2005. A second dataset was created by applying an adjustment according to linear equations relating MODIS tree cover to Quickbird-derived (ground reference) tree cover estimates. An image segmentation for each dataset grouped pixels representing similar tree cover into polygonal features that form the map of the transition zone. Each feature represents an area much larger than the 500m MODIS pixel to mitigate the VCF’s overestimation of tree cover in lightly forested regions. Comparisons of both the unadjusted and adjusted average tree cover data were made with (1) two existing tree line definitions aggregated for each 1° longitudinal interval in North America and Eurasia and (2) Landsat-derived Canadian forest cover. The adjusted version of the MODIS VCF tree cover product generally improved its agreement with independent tree line and forest cover data in areas of low tree cover. Those polygons with an average tree cover in the range of 5-20% and an average tree cover below 5% but with a standard deviation greater than 5% at the northern edge of the boreal forests of North America and Eurasia were used to identify the transition zone.
Presentation Type: Poster
Poster Session: Ecosystems Science
NASA TE Funded Awards Represented:
Ranson, Jon
Amount, Spatial Distribution, and Statistical Uncertainty of Aboveground Carbon Stocks in the Circumpolar Boreal Forest