Spectro-spatial relationship between UAV derived high resolution DEM and SWIR hyperspectral data: application to an ombrotrophic peatland

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1117/12.2277874
AuthorSearch for: 1; Search for: ; Search for: ; Search for: 1; Search for: 1
Name affiliation
  1. National Research Council of Canada. Aerospace
FormatText, Article
Proceedings titleRemote Sensing for Agriculture, Ecosystems, and Hydrology XIX
Series titleProceedings of SPIE; no. 10421
ConferenceRemote Sensing for Agriculture, Ecosystems, and Hydrology, 11-14 September, 2017, Warsaw, Poland
ISSN0277-786X
1996-756X
ISBN9781510613065
9781510613072
Article number104210P-1
Pages# of pages: 13
Abstract
Peatlands cover ~3% of the globe and are key ecosystems for climate regulation. To better understand the potential effects of climate change in peatlands, a major challenge is to determine the complex relationship between hydrology, microtopography, vegetation patterns, and gas exchange. Here we study the spectral and spatial relationship of microtopographic features (e.g. hollows and hummocks) and near-surface water through narrow-band spectral indices derived from hyperspectral imagery. We used a very high resolution digital elevation model (2.5 cm horizontal, 2.2 cm vertical resolution) derived from an UAV based Structure from Motion photogrammetry to map hollows and hummocks in the peatland area. We also created a 2 cm spatial resolution orthophoto mosaic to enhance the visual identification of these hollows and hummocks. Furthermore, we collected SWIR airborne hyperspectral (880-2450 nm) imagery at 1 m pixel resolution over four time periods, from April to June 2016 (phenological gradient: vegetation greening). Our results revealed an increase in the water indices values (NDWI1640 and NDWI2130) and a decrease in the moisture stress index (MSI) between April and June. In addition, for the same period the NDWI2130 shows a bimodal distribution indicating potential to quantitatively assess moisture differences between mosses and vascular plants. Our results, using the digital surface model to extract NDWI2130 values, showed significant differences between hollows and hummocks for each time period, with higher moisture values for hollows (i.e. moss dominated). However, for June, the water index for hummocks approximated the values found in hollows. Our study shows the advantages of using fine spatial and spectral scales to detect temporal trends in near surface water in a peatland.
Publication date
PublisherSociety of Photo-Optical Instrumentation Engineers (SPIE)
LanguageEnglish
Peer reviewedYes
NPARC number23002407
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