Thermal infrared spectroscopy in the laboratory and field in support of land surface remote sensing

Abstract

Thermal infrared (TIR) spectra of Earth surface materials are used in a wide variety of applications. These applications can fall into either of two groups: (a) where the TIR emissivity spectra themselves are the primary interest, and are used to determine the chemical/physical parameters of minerals and rocks, soil, vegetation and man-made materials, or (b) where the primary interest is in the temperature of the objects under study, and where emissivity spectra are required inorder to best determine kinetic from radiant temperature. Unlike visible-near infrared (VNIR) and shortwave infrared (SWIR) instruments, TIR spectroscopy instrumentation often requires customization in order to acquire reliable and reproducible data, making thermal spectroscopy a potentially complex process. Within this chapter we intend to provide a simple starting point for the new user of thermal infrared spectroscopy, and a synoptic overview of the technique for the more experienced practitioner. We discuss the theoretical background, give examples of instrument setups and provide typical measurement scenarios for a number of land applications.