Potential of Sentinel-2 spectral configuration to assess rangeland quality

Abel Ramoelo*, Moses Cho, Renaud Mathieu, Andrew K. Skidmore

*Corresponding author for this work

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Sentinel-2 is intended to improve vegetation assessment at local to global scales. Today, estimation of leaf nitrogen (N) as an indicator of rangeland quality is possible using hyperspectral systems. However, few studies based on commercial imageries have shown a potential of the red-edge band to accurately predict leaf N at the broad landscape scale. We intend to investigate the utility of Sentinel-2 for estimating leaf N concentration in the African savanna. Grass canopy reflectance was measured using the analytical spectral device (ASD) in concert with leaf sample collections for leaf N chemical analysis. ASD reflectance data were resampled to the spectral bands of Sentinel-2 using published spectral response functions. Random forest (RF), partial least square regression (PLSR), and stepwise multiple linear regression (SMLR) were used to predict leaf N using all 13 bands. Using leave-one-out cross validation, the RF model explained 90% of leaf N variation, with a root mean square error of 0.04 (6% of the mean), which is higher than that of PLSR and SMLR. Using RF, spectral bands centered at 705 nm (red edge) and two shortwave infrared bands centered at 2190 and 1610 nm were found to be the most important bands in predicting leaf N.

Original languageEnglish
Article number094096
Number of pages11
JournalJournal of Applied Remote Sensing
Volume9
Issue number1
DOIs
Publication statusPublished - 7 Aug 2015
Externally publishedYes

Keywords

  • Sentinel-2
  • leaf nitrogen
  • WorldView-2
  • RapidEye
  • red-edge band
  • random forest

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