Ground Truth Trekking: Validating Interpretations of Satellite-Based Change in Reflectance Metrics Across Scales and Resolutions Using MODIS, Landsat, and Worldview Imagery of South-Central and Arctic Alaska
Abstract
Climate warming's polar amplification and elevational dependence suggest that very rapid vegetation change will occur in high-latitude mountain ranges, most of which are located in remote wilderness. Detecting change in these regions is accomplished most cost-effectively using satellite platforms carrying passive reflectance sensors. Unfortunately, ground-truthing relative to the spatial scale of satellite coverage has rarely been undertaken in the wilderness of Alaska. Here we place "boots-on-the-ground" to investigate changes suggested by 20 years of NASA MODIS (250m pixels); 30 years of NASA/USGS Landsat (30m pixels); and recent DigitalGlobe WorldView imagery (1m pixels). We present preliminary findings based on 10-500 km-long field-campaigns pertinent to changing ecosystem functions in two Alaskan mountain ranges at three scales: (1) Determining possible mechanisms behind greening that is indicated by MODIS in the central Brooks Range. (2) Estimating biomass of montane shrubs that have moved uphill in the western Chugach Mountains as suggested by Landsat. (3) Dating the year of establishment for white spruce individuals that underwent late-20th century long-distance dispersal across the western Brooks Range as identified in WorldView. The combination of wilderness field-work and satellite imagery offers a cost-effective means of quantifying and validating the rate and nature of ongoing vegetation change occurring across boreal and Arctic ecosystems.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMB099...07D
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCES;
- 0475 Permafrost;
- cryosphere;
- and high-latitude processes;
- BIOGEOSCIENCES