Arctic tundra vegetation functional types based on photosynthetic physiology and optical properties

Karl Fred Huemmrich, NASA GSFC/UMBC, karl.f.huemmrich@nasa.gov (Presenter)

Climate change in tundra regions may alter vegetation species composition and ecosystem carbon balance, and remote sensing provides critical tools for monitoring these changes. Measurements of pure patches of key plant functional types (lichens, mosses, and vascular plants) in sedge tundra at Barrow AK, show three different values of light use efficiency (LUE). Also, discriminant analysis of patch reflectance identifies seven spectral bands that can separate each functional type and nongreen material (bare soil and dead leaves). These results were tested along a 100 m transect across the tundra. At every meter, midsummer spectral reflectance and vegetation coverage were measured. LUE estimated from coverage fractions varies widely, even over short distances. The patch-level discriminant functions successfully unmixed cover fractions of the functional types, with standard errors well within the expected measurement error of the coverage. The unmixture algorithms were then applied to EO-1 Hyperion data to provide a description of the spatial distribution of vegetation functional types, and, from that, the distribution of LUE. These results demonstrate the use of hyperspectral remote sensing to provide direct estimates of tundra ecosystem LUE variability.

Presentation Type:  Poster

Session:  Other   (Tue 11:30 AM)

Associated Project(s): 

• Middleton, Betsy: Spectral Bio-Indicators of Ecosystem Photosynthetic Efficiency II: Synthesis and Integration ...details

Poster Location ID: 213