Synergy of active and passive airborne thermal infrared systems for surface compositional mapping

Abstract

Abstract. NASA thermal infrared multispectral scanner (TIMS) and Commonwealth Scientific Industrial Research Organisation mid-infrared airborne CO2 laser spectrometer (MIRACO2LAS) data were acquired over the Mount Fitton area, South Australia, in order to evaluate their combined use for geological mapping and mineral exploration. TIMS is a passive, imaging system with six spectral bands in the thermal infrared wavelength region (8-12/xm), whereas MIRACO2LAS is an active, profiling system with -100 spectral bands in the 9-11 /xm spectral range. The TIMS and CO2 laser data (emissivity variations for TIMS and apparent reflectance for MIRACO2LAS) were processed to enhance spectral information related to the surface composition. This spectral information was compared with existing geological maps and field emissivity spectra. Known geological units were well discriminated in the TIMS imagery, including a range of quartz-rich and carbonate-rich sedimentary units, as well as several previously unmapped areas of alteration in the carbonate rocks. However, the broadband spectral resolution of TIMS did not allow identification of discrete mineral constituents. In contrast, the high spectral resolution MIRACO2LAS data provided diagnostic spectral information about a range of minerals present including quartz, dolomite, talc, and tremolite, albeit, along discrete profiles. The widths of some of these diagnostic spectral features were less than 0.2/xm wide, which is half the resolution of the TIMS band passes (0.4/xm). The MIRACO2LAS spectra closely matched the shape, location, and depth of spectra of field samples measured by both a field emission spectrometer and a laboratory laser spectrometer. Pure mineral spectra measured by the (bidirectional) laboratory laser spectrometer also closely matched those measured by a conventional laboratory spectrometer measuring directional hemispherical reflectance.

Multi- and hyperspectral geologic remote sensing: A review

“…The TIR (8-14 m) and the MIR (3-5 m) are areas that have great potential for geologic remote sensing studies, but that have been under-investigated probably due to (1) the complexity of the physics (e.g., volume scattering effects in the TIR and emissivity and temperature interference in the MIR) and (2) lack of field/laboratory spectrometers and (airborne/spaceborne) hyperspectral data. In the early 1990s, Mike Abrams showed the added value of combined TIR and SWIR observations (Abrams et al, 1991;Hook et al, 1998). From TIR multispectral scanner data Simon Hook and co-authors showed the type of information that could be revealed (Hook et al, 1992(Hook et al, , 1994Hook and Kahle, 1996).…”

Comparative Analysis of Split-Window and Single-Channel Algorithms for Land Surface Temperature Retrieval of a Pseudo-Invariant Target

“…These features are related to the differences in the SiO content in the soil, which has minimal emissivity and therefore maximum absorption (reststrahlen effect). This behavior is observed in silicates, such as quartz, having reststrahlen effects observed around 8,2µm and 9,3µm (Hook et al 1998). Consequently, TIR region (8µm-14µm) is effective for this kind of study, in which the material emissive properties are predominant relative to its reflective properties (Hook et al 2005;Li et al 2013;Grondona et al 2019).…”

Detecção de quartzo e argilominerais para o monitoramento de degradação de terras a partir de dados do infravermelho termal do sensor aster

“…Figura 4 -Fluxograma de etapas de processamento das imagens ASTER/TIR. Hook et al, 1998;Ramsey et al, 1999). O alto grau de correlac ¸ão entre bandas em dados termais deve-se ao fato de que os valores de radiância são func ¸ão direta da temperatura e emissividade da superfície (Vaughan et al, 2005).…”