Abstract
Abstract. The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is a prototype of an imaging Fourier Transform Spectrometer (FTS) for PREMIER, a former candidate mission for ESA's Earth Explorer 7. GLORIA is deployed on board various research aircraft such as the Russian M55 Geophysica or the German HALO. The instrument provides detailed infrared images of the Upper Troposphere/Lower Stratosphere (UTLS) region, which plays a crucial role in the climate system. GLORIA uses a two-dimensional detector array for infrared limb observations in emission and therefore needs large-area blackbody radiation sources (126 mm × 126 mm) for calibration. In order to meet the highly demanding uncertainty requirements for the scientific objectives of the GLORIA missions and due to the sophisticated tomographic evaluation scheme, the spatial distribution of the radiance temperature of the blackbody calibration sources has to be determined with an uncertainty of about 0.1 K. Since GLORIA is exposed to the hostile environment of the UTLS with mutable low temperature and pressure, an in-flight calibration system has to be carefully designed to cope with those adverse circumstances. The GLORIA in-flight calibration system consists of two identical weight-optimised high-precision blackbody radiation sources, which are independently stabilised at two different temperatures. The two point calibration is in the range of the observed atmospheric infrared radiance emissions with 10 K below and 30 K above ambient temperature, respectively. Thermo-Electric Coolers are used to control the temperature of the blackbody radiation sources offering the advantage of avoiding cryogens and mechanical coolers. The design and performance of the GLORIA in-flight calibration system is presented. The blackbody calibration sources have been comprehensively characterised for their spatially (full aperture) and spectrally (7 to 13 μm) resolved radiation properties in terms of radiance temperatures traceable to the International Temperature Scale (ITS-90) at the Physikalisch-Technische Bundesanstalt (PTB), the national metrology institute of Germany.
Highlights
The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an airborne imaging Fourier Transform Spectrometer (FTS) deployed in the belly pod of the new German research aircraft HALO as well as on board the high-flying Russian research plane M55 Geophysica (Riese et al, 2014; Friedl-Vallon et al, 2014)
The Upper Troposphere/Lower Stratosphere (UTLS) plays a crucial role for the climate system (e.g. Solomon et al, 2007), as changes in the structure and in the chemical composition of this region result in large changes in atmospheric radiative forcing leading to significant changes in surface temperature
This paper describes the design and performance of the GLORIA in-flight calibration system, which has been comprehensively characterised for its spatially and spectrally (7 to 13 μm) resolved radiation properties in terms of radiance temperature traceable to the International Temperature Scale (ITS-90) at the Physikalisch-Technische Bundesanstalt (PTB), the national metrology institute of Germany
Summary
The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an airborne imaging Fourier Transform Spectrometer (FTS) deployed in the belly pod of the new German research aircraft HALO as well as on board the high-flying Russian research plane M55 Geophysica (Riese et al, 2014; Friedl-Vallon et al, 2014). Three-dimensional fields of water vapour, ozone, transport tracers, and chemically active species with high vertical (few 100s m) and horizontal resolution (few 10s km) as well as low uncertainties are mandatory to quantify physical and chemical processes controlling the composition and structure of the UTLS. To achieve this objective, GLORIA uses a twodimensional detector array for detailed infrared limb observations in emission. Up to 128 × 128 pixels are used by the Michelson FTS providing over 16 000 simultaneous spectrally resolved limb views This allows for measurements of atmospheric temperature fields, clouds parameters, aerosols, water vapour, ozone, and about ten other trace species. The blackbody radiation sources were tested under lab conditions as well as in a climatic and environmental test chamber in order to verify their performance in various atmospheric environments
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
