EGU23-11146
https://doi.org/10.5194/egusphere-egu23-11146
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Expanding the Emirates Mars Infrared Spectrometer (EMIRS) Science Dataset using EMIRS off-axis detectors

George H. Cann1, Roland M. B. Young1,2, Christopher S. Edwards3, Michael D. Smith4, and Michael J. Wolff5
George H. Cann et al.
  • 1National Space Science and Technology Center, United Arab Emirates University, Al Ain, UAE (george.cann@uaeu.ac.ae).
  • 2College of Science, Department of Physics, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
  • 3Department of Physics and Astronomy, Northern Arizona University, NAU BOX 6010, Flagstaff, AZ 86011, USA.
  • 4NASA Goddard Space Flight Center, Greenbelt, MD, USA.
  • 5Space Science Institute, Boulder, CO, USA.

Keywords: Mars, Atmosphere, EMM, Emirates Mars Infrared Spectrometer, Off-axis Detectors.

Introduction: The Emirates Mars Mission (EMM) Emirates Mars InfraRed Spectrometer (EMIRS) instrument is a Fourier Transform Infrared (FTIR) spectrometer designed to observe the Martian disk, with the primary scientific objective of determining the three-dimensional thermal state of the lower atmosphere and its diurnal variability on sub-seasonal timescales [1].

EMIRS uses a 3x3 array of deuterated L-alanine doped triglycine sulfate (DLaTGS) pyroelectric detectors [1], however, following the integration of the EMIRS electronics with the optical and mechanical hardware it was observed that the performance of the off-axis (non-central) detectors of the array were lower than expected [1]. Investigations into the performance of these off-axis detectors has so far yielded inconclusive root causes. As EMIRS could meet its primary science objective with the on-axis (central) detector and was subject to a pressing instrument schedule, a project level decision was made to forgo any additional investigation and instead rely on the on-axis detector [1][2].

Method: In this study we present a comparison of observations captured by EMIRS from the off-axis detectors against the on-axis detector. The comparison is performed via a top-down and bottom-up pathway approach using the EMM Science Team processing pipeline. The top-down pathway focuses on the effects of the pre-processing steps on the detector interferograms, whereas the bottom-up approach compares calibrated radiances derived from the pipeline with and without applying the pre-processing steps [3] [4]. Correction of these issues will expand the retrieval derived products by a factor of five.

Results: The top-down comparison shows differences in terms interferogram amplitude and phase error between on and off-axis detectors. We assess the feasibility of correction, then apply correction methods to a subset of EMIRS observations, and propose the root cause of the issues. This study is presented along with the generation of a joint dataset of near-mutual EMIRS and EXI (Emirates eXploration Imager) observations [5].

Acknowledgements: The authors would like to acknowledge support by a Joint Research Agreement between the Mohammed Bin Rashid Space Centre (MBRSC) and the National Space Science and Technology Center (NSSTC), UAE University (UAEU).

References:

[1] Edwards, C. S., et al. (2021). Space Science Reviews (2021) 217:77.

[2] Amiri, H.E. S., et al. (2022). Space Science Reviews (2022) 218:4.

[3] Forman, M. L., et al. (1966). J. Opt. Soc. Am. 56(1), 59–63.

[4] Christensen, V.E., et al. (2018). Space Science Reviews (2018), 215:87.

[5] Jones, A. R., et al. (2021). Space Science Reviews (2021) 217:81.

How to cite: Cann, G. H., Young, R. M. B., Edwards, C. S., Smith, M. D., and Wolff, M. J.: Expanding the Emirates Mars Infrared Spectrometer (EMIRS) Science Dataset using EMIRS off-axis detectors, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11146, https://doi.org/10.5194/egusphere-egu23-11146, 2023.