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Ammonia (NH 3) is the major alkaline species in the atmosphere and plays an important role in aerosol formation, which affects local air quality and the radiation budget. NH 3 in the upper troposphere and lower stratosphere (UTLS) is difficult to detect, and only limited observations are available. We present two-dimensional trace gas measurements of NH 3 obtained by the airborne infrared imaging limb sounder GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) that was operated on board the research aircraft Geophysica within the Asian monsoon anticyclone during the StratoClim campaign (July 2017) and on board HALO (the High Altitude and LOng Range research aircraft) above the South Atlantic during the SouthTRAC campaign (September–November 2019). We compare these GLORIA measurements in the UTLS with results of the CAMS (Copernicus Atmosphere Monitoring Service) reanalysis and forecast model to evaluate its performance. The GLORIA observations reveal large enhancements of NH 3 of more than 1 ppbv in the Asian monsoon upper troposphere but no clear indication of NH 3 in biomass burning plumes in the upper troposphere above the South Atlantic above the instrument's detection limit of around 20 pptv. In contrast, CAMS reanalysis and forecast simulation results indicate strong enhancements of NH 3 in both measured scenarios. Comparisons of other retrieved pollution gases, such as peroxyacetyl nitrate (PAN), show the ability of CAMS models to generally reproduce the biomass burning plumes above the South Atlantic. However, NH 3 concentrations are largely overestimated by the CAMS models within these plumes. We suggest that emission strengths used by CAMS models are of lower accuracy for biomass burning in comparison to agricultural sources in the Asian monsoon. Further, we suggest that loss processes of NH 3 during transport to the upper troposphere may be underestimated for the biomass burning cases above the South Atlantic. Since NH 3 is strongly undersampled, in particular at higher altitudes, we hope for regular vertically resolved measurements of NH 3 from the proposed CAIRT (Changing-Atmosphere Infra-Red Tomography Explorer) mission to strengthen our understanding of this important trace gas in the atmosphere. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is the major alkaline species in the atmosphere and plays an important role in aerosol formation, which affects local air quality and the radiation budget. NH3 in the Upper Troposphere and Lower Stratosphere (UTLS) is difficult to detect and only limited observations are available. We present two dimensional trace gas measurements of NH3 obtained by the airborne infrared imaging limb sounder GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) that has been operated onboard the research aircraft Geophysica within the Asian Monsoon during the StratoClim campaign (July 2017) and onboard HALO (High Altitude and Long Range Research Aircraft) above the South Atlantic during the SouthTRAC campaign (September-November 2019). We compare these GLORIA measurements in the UTLS with results of the CAMS (Copernicus Atmosphere Monitoring Service) reanalysis and forecast model. The GLORIA observations reveal large enhancements of NH3 of more than 1 ppbv in the Asian Monsoon upper troposphere, but no clear indication of NH3 in biomass burning plumes in the upper troposphere above the South Atlantic above the instrument's detection limit of around 20 pptv. In contrast, CAMS reanalysis and forecast simulation results indicate strong enhancements of NH3 in both measured scenarios. Comparisons of other retrieved pollution gases, such as peroxyacetyl nitrate (PAN) show the ability of CAMS models to reproduce the biomass burning plumes above the South Atlantic in general. However, NH3 concentrations are largely overestimated by the CAMS models within these plumes. We suggest that emission strengths used by CAMS models are of different accuracy for biomass burning and agricultural sources in the Asian Monsoon. Further, we suggest that loss processes of NH3 during transport to the upper troposphere may be underestimated for the biomass burning cases above the South Atlantic. Since NH3 is strongly undersampled, in particular at higher altitudes, we hope for regular vertically resolved measurements of NH3 from the proposed CAIRT mission to strengthen our understanding of this important trace gas in the atmosphere. [ABSTRACT FROM AUTHOR]

Analyses of the mesosphere and lower thermosphere suffer from a lack of global measurements. This is problematic because this region has a complex dynamic structure, with gravity waves playing an important role. A limb-sounding spatial heterodyne interferometer (SHI) was developed to obtain atmospheric temperature retrieved from the O2 A-band emission, which can be used to derive gravity wave parameters in this region. The 2-D spatial distribution of the atmospheric scene is captured by a focal plane array. The SHI superimposes the spectral information onto the horizontal axis across the line-of-sight (LOS). In the usual case, the instrument exploits the horizontal axis to obtain spectral information and uses the vertical axis to get spatial information, i.e. temperature observations at the corresponding tangent points. This results in a finely resolved 1-D vertical atmospheric temperature profile. However, this method does not make use of the horizontal across-LOS information contained in the data. In this paper a new processing method is investigated, which uses single-sided interferograms to gain horizontal across-LOS information about the observed temperature field. Hereby, the interferogram is split, and each side is mirrored at the centre of the horizontal axis. Each side can then be used to retrieve an individual 1-D temperature profile. The location of the two retrieved temperature profiles is analysed using prescribed horizontal temperature variations, as it is needed for deriving wave parameters. We show that it is feasible to derive two independent temperature profiles, which however will increase the requirements of an accurate calibration and processing. [ABSTRACT FROM AUTHOR]

In this study, we present simultaneous airborne measurements of peroxyacetyl nitrate (PAN), ethane (C2H6), formic acid (HCOOH), methanol (CH3OH), and ethylene (C2H4) above the South Atlantic in September and October 2019. Observations were obtained from the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA), as twodimensional altitude cross-sections along the flight path. The flights were part of the SouthTRAC (Transport and Composition in the Southern Hemisphere Upper Troposphere/Lower Stratosphere) campaign with the German High Altitude and Long range research Aircraft (HALO). On two flights (8 September 2019 and 7 October 2019), large enhancements of all these substances were found between 7 and 14 km altitude with maximum volume mixing ratios (VMRs) of 1000 pptv of PAN, 1400 pptv for C2H6, 800 pptv for HCOOH, 4500 pptv for CH3OH, and 200 pptv for C2H4. One flight shows a common filamentary structure in the trace gas distributions, while the second flight is characterized by one large plume. Using backward trajectories, we show that measured pollutants are likely originating from South America and central Africa, where elevated PAN VMRs are visible at the surface layer of the Copernicus Atmosphere Monitoring Service (CAMS) model during the weeks before both measurements. In comparison to simulation results of the CAMS reanalysis interpolated onto the GLORIA measurement geolocations, we show that the model is able to reproduce the overall structure of the measured pollution trace gas distributions. For PAN, the absolute VMRs are in agreement with the GLORIA measurements, too. However, C2H6 and HCOOH are generally underestimated by the model, while CH3OH and C2H4, the species with the shortest atmospheric lifetimes of the discussed pollution trace gases, are overestimated by CAMS. The good agreement between model and observations for PAN suggests that the general transport pathways and emissions locations are well captured by the model. The poorer agreement for other species is therefore most likely linked to model deficiencies in the representation of loss processes and emission strength. [ABSTRACT FROM AUTHOR]

The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an infrared imaging FTS spectrometer with a 2-D infrared detector operated on two high flying research aircrafts. It has flown on eight campaigns and measured along more than 300 000km of flight track. This paper details our instrument calibration and characterization efforts, which in particular leverage almost exclusively in-flight data. First, we present the framework of our new calibration scheme, which uses information from all three available calibration measurements (two blackbodies and upward pointing "deep space" measurements). Part of this scheme is a new correction algorithm correcting the erratically changing non-linearity of a subset of detector pixels and the identification of remaining bad pixels. Using this new calibration, we derive a 1-σ bound of 1% on the instrumental gain error and a bound of 30nWcm-2sr-1cm on the instrumental offset error. We show how we can examine the noise and spectral accuracy for all measured atmospheric spectra and derive a spectral accuracy of 5 ppm, on average. All these errors are compliant with the initial instrument requirements. We also discuss, for the first time, the pointing system of the GLORIA instrument. Combining laboratory calibration efforts with the measurement of astronomical bodies during the flight, we can derive a pointing accuracy of 0.032°, which corresponds to one detector pixel. The paper concludes with a brief study on how these newly characterised instrumental parameters affect temperature and ozone retrievals.We find that, first, the pointing uncertainty and, second, the instrumental gain uncertainty introduce the largest error in the result. [ABSTRACT FROM AUTHOR]

CubeSats have become very popular in the past decades which yields to a continuously increasing number of developers in the academic field. For all science missions, customized payload electronics have to be developed, depending on measurement tasks and requirements. Especially for the deployment of more complex remote sensing payloads, state-of-the-art performance is needed to provide operational control and specific data processing of the image sensors. With a highly integrated System on Module (SoM) architecture low resource requirements for both, power and mass, but moderate to high processing power capabilities are available. The major advantages are flexibility, (re)programmability, modularity and module re-use in respect to lower development time and costs. However, it is a challenge to make this module suitable to implement it into space environment. With an efficient approach a radiation tolerant characteristics will be achieved by modelling the radiation environment, estimating the hazards at module level and reducing it to acceptable risks with necessary measures of mitigation techniques. This approach results into a sensor electronics which combines hardware and software redundancies to assure system availability and reliability for long life science missions in Low-Earth-Orbits (LEO). A dual imager electronics design is presented which uses module architecture based on reconfigurable hardware with a processing unit as high integrated commercial-off-the-shelf (COTS) components integrated in a 6U CubeSat. First qualification and acceptance tests with the electronics will be shown. [ABSTRACT FROM AUTHOR]