Remote Sensing (Jun 2022)

First Observations of Mars Atmosphere and Ionosphere with Tianwen-1 Radio-Occultation Technique on 5 August 2021

  • Xiong Hu,
  • Xiaocheng Wu,
  • Shuli Song,
  • Maoli Ma,
  • Weili Zhou,
  • Qingchen Xu,
  • Lei Li,
  • Cunying Xiao,
  • Xie Li,
  • Chi Wang,
  • Qinghui Liu,
  • Lue Chen,
  • Guangming Chen,
  • Jianfeng Cao,
  • Mei Wang,
  • Peijia Li,
  • Zhanghu Chu,
  • Bo Xia,
  • Junfeng Yang,
  • Cui Tu,
  • Dan Liu,
  • Simin Zhang,
  • Quan Zhang,
  • Zheng Li

DOI
https://doi.org/10.3390/rs14112718
Journal volume & issue
Vol. 14, no. 11
p. 2718

Abstract

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The radio-occultation technique can provide vertical profiles of planetary ionospheric and atmospheric parameters, which merit the planetary-climate and space-weather scientific research so far. The Tianwen-1 one-way single-frequency radio-occultation technique was developed to retrieve Mars ionospheric and atmospheric parameters. The first radio-occultation event observation experiment was conducted on 5 August 2021. The retrieved excess Doppler frequency, bending angle, refractivity, electron density, neutral mass density, pressure and temperature profiles are presented. The Mars ionosphere M1 (M2) layer peak height is at 140 km (105 km) with a peak density of about 3.7 × 1010 el/m3 (5.3 × 1010 el/m3) in the retrieved electron-density profile. A planetary boundary layer (−2.35 km~5 km), a troposphere (temperature decreases with height) and a stratosphere (24 km–40 km) clearly appear in the retrieved temperature profile below 50 km. Results show that Tianwen-1 radio occultation data are scientifically reliable and useful for further Mars climate and space-weather studies.

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