Project Funding: 2009 - 2012

NRA: 2008 NASA: Terrestrial Ecology   

Funded by NASA

Abstract:
The goal of this project is to develop methods based on exploiting the structural rather than the spectral signals in NASA Earth Observing System data from the Multiangle Imaging SpectroRadiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) in order to map changes in northern high latitude vegetation. The focus is on estimating shrub abundance and structure in arctic tundra to decouple the contributions of different terrestrial factors (vegetation, soils, surface water) to terrestrial albedo. A strong structural signal is available in multiangle MISR and MODIS data because of the high solar zenith angles at high latitudes that enhance shadowing from woody plants. This structural approach builds on recent advances in using multiangle EOS data for mapping woody canopies and has several advantages: explicitly acknowledging and exploiting structural effects provides alternative, potentially less ambiguous measures than spectral indices; MISR and MODIS cover large areas efficiently, allowing evaluation of trajectories through time from 2000; and MISR views closer to the solar principal plane where the structural signal is strongest. Other remote sensing methods (commercial high resolution imaging, hyperspectral imaging, active instruments) do not have records that extend back to the start of the EOS era, sample too infrequently, and/or are too costly for annual mapping over large areas. Current maps of pan-arctic vegetation are based on spectral vegetation indices that are compound metrics that reflect vegetation cover, photosynthetic activity, foliage depth, canopy architecture, and soil color and brightness; no temporally dynamic maps of woody plant abundance, canopy height, or aboveground woody biomass exist that allow the assessment of trends in structural parameters. Reference data will be obtained from a number of wellcharacterized field sites in Alaska, Russia, and N. Europe, through an important collaboration with the International Polar Year PPS Arctic Program, field survey, and the construction of high resolution maps.

Publications:

Duchesne, R. R., Chopping, M. J., Tape, K. D., Wang, Z., Schaaf, C. L. 2018. Changes in tall shrub abundance on the North Slope of Alaska, 2000-2010. Remote Sensing of Environment. 219, 221-232. DOI: 10.1016/j.rse.2018.10.009

Wang, Z., Schaaf, C. B., Chopping, M. J., Strahler, A. H., Wang, J., Roman, M. O., Rocha, A. V., Woodcock, C. E., Shuai, Y. 2012. Evaluation of Moderate-resolution Imaging Spectroradiometer (MODIS) snow albedo product (MCD43A) over tundra. Remote Sensing of Environment. 117, 264-280. DOI: 10.1016/j.rse.2011.10.002

Chopping, M. 2011. CANAPI: canopy analysis with panchromatic imagery. Remote Sensing Letters. 2(1), 21-29. DOI: 10.1080/01431161.2010.486805

Tape, K. (2010). The Changing Arctic Landscape, University of Alaska Press, 132 pp., ISBN: 9781602230804

Selkowitz, D. J. 2010. A comparison of multi-spectral, multi-angular, and multi-temporal remote sensing datasets for fractional shrub canopy mapping in Arctic Alaska. Remote Sensing of Environment. 114(7), 1338-1352. DOI: 10.1016/j.rse.2010.01.012

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• A New NACP Data Set: Woody Vegetation Characteristics of 1,039 Sites across the North Slope, Alaska   --   (Rocio Duchesne, Mark James Chopping, Ken Tape)   [abstract]   [poster]

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• Tall Shrub Abundance on the North Slope of Alaska from MISR, 2000-2010   --   (Mark James Chopping, Rocio Duchesne, Zhuosen Wang, Crystal Schaaf, Ken Tape, Tian Yao)   [abstract]   [poster]

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Shrub Abundance in Alaskan Arctic Tundra from MODIS Reflectance Anisotropy   --   (Mark James Chopping, Rocio Duchesne, Zhuosen Wang, Crystal Schaaf, Kenneth Tape)   [abstract]   [poster]

2010 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• CANAPI: Canopy Analysis with Panchromatic Imagery for Validation of Moderate Resolution Canopy Structure Products   --   (Mark James Chopping, Xiaoyuan Yang, Crystal Schaaf, Alan Strahler)   [abstract]   [poster]
• Estimating Shrub Cover in Arctic Tundra from Structural Metrics and Effects on Albedo   --   (Mark James Chopping, Kenneth Tape, Sawahiko Shimada, Rocio Raquel Duchesne, Zhuosen Wang, Crystal Schaaf)   [abstract]   [poster]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile
• North American Carbon Program (NACP) Project Profile