Spectral identification and quantification of salts in the Atacama Desert

Jennifer Harris, C. R. Cousins, M. W. Claire

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

Salt minerals are an important natural resource. The ability to quickly and remotely identify and quantify salt deposits and salt contaminated soils and sands is therefore a priority goal for the various industries and agencies that utilise salts. The advent of global hyperspectral imagery from instruments such as Hyperion on NASA’s Earth-Observing 1 satellite has opened up a new source of data that can potentially be used for just this task. This study aims to assess the ability of Visible and Near Infrared (VNIR) spectroscopy to identify and quantify salt minerals through the use of spectral mixture analysis. The surface and near-surface soils of the Atacama Desert in Chile contain a variety of well-studied salts, which together with low cloud coverage, and high aridity, makes this region an ideal testbed for this technique. Two forms of spectral data ranging 0.35 – 2.5 μm were collected: laboratory spectra acquired using an ASD FieldSpec Pro instrument on samples from four locations in the Atacama desert known to have surface concentrations of sulfates, nitrates, chlorides and perchlorates; and images from the EO-1 satellite’s Hyperion instrument taken over the same four locations. Mineral identifications and abundances were confirmed using quantitative XRD of the physical samples. Spectral endmembers were extracted from within the laboratory and Hyperion spectral datasets and together with additional spectral library endmembers fed into a linear mixture model. The resulting identification and abundances from both dataset types were verified against the sample XRD values. Issues of spectral scale, SNR and how different mineral spectra interact are considered, and the utility of VNIR spectroscopy and Hyperion in particular for mapping specific salt concentrations in desert environments is established. Overall, SMA was successful at estimating abundances of sulfate minerals, particularly calcium sulfate, from both hyperspectral image and laboratory sample spectra, while abundance estimation of other salt phase spectral end-members was achieved with a higher degree of error.
Original languageEnglish
Title of host publicationEarth Resources and Environmental Remote Sensing/GIS Applications VII
EditorsUlrich Michel, Karsten Schulz, Manfred Ehlers, Konstantinos G. Nikolakopoulos, Daniel Civco
PublisherSPIE
Volume10005
ISBN (Electronic)9781510604155
ISBN (Print)9781510604148
DOIs
Publication statusPublished - 16 Oct 2016
EventEarth Resources and Environmental Remote Sensing/GIS Applications VII - Edinburgh, United Kingdom
Duration: 27 Sept 201629 Sept 2016
http://spie.org/Publications/Proceedings/Volume/10005

Publication series

NameProceedings of SPIE
PublisherSPIE
Volume10005
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceEarth Resources and Environmental Remote Sensing/GIS Applications VII
Country/TerritoryUnited Kingdom
CityEdinburgh
Period27/09/1629/09/16
Internet address

Keywords

  • Spectra Mixture Analysis
  • Salts
  • Hyperion
  • Hyperspectral
  • Atacama Desert

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