Articles | Volume 11, issue 3
Atmos. Meas. Tech., 11, 1653–1668, 2018
Atmos. Meas. Tech., 11, 1653–1668, 2018

Research article 26 Mar 2018

Research article | 26 Mar 2018

Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: sensitivity study for satellite observation

Tomohiro O. Sato1, Takao M. Sato2,1, Hideo Sagawa3, Katsuyuki Noguchi4, Naoko Saitoh5, Hitoshi Irie5, Kazuyuki Kita6, Mona E. Mahani1,7, Koji Zettsu1, Ryoichi Imasu8, Sachiko Hayashida4, and Yasuko Kasai1,9,10,11 Tomohiro O. Sato et al.
  • 1Big Data Analytics Laboratory, National Institute of Information and Communications Technology, Tokyo, Japan
  • 2Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Kanagawa, Japan
  • 3Department of Astrophysics and Atmospheric Sciences, Kyoto Sangyo University, Kyoto, Japan
  • 4Faculty of Science, Nara Women's University, Nara, Japan
  • 5Center for Environmental Remote Sensing, Chiba University, Chiba, Japan
  • 6College of Science, Ibaraki University, Ibaraki, Japan
  • 7Department of Geophysics, Tohoku University, Miyagi, Japan
  • 8Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
  • 9Terahertz Technology Research Center, National Institute of Information and Communications Technology, Tokyo, Japan
  • 10Department of Chemical Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan
  • 11Graduate School of Pure and Applied Sciences, Tsukuba University, Ibaraki, Japan

Abstract. We performed a feasibility study of constraining the vertical profile of the tropospheric ozone by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR), and microwave (MW) ranges, measured from space. This work provides, for the first time, a quantitative evaluation of the retrieval sensitivity of the tropospheric ozone by adding the MW measurement to the UV and TIR measurements. Two observation points in East Asia (one in an urban area and one in an ocean area) and two observation times (one during summer and one during winter) were assumed. Geometry of line of sight was nadir down-looking for the UV and TIR measurements, and limb sounding for the MW measurement. The retrieval sensitivities of the ozone profiles in the upper troposphere (UT), middle troposphere (MT), and lowermost troposphere (LMT) were estimated using the degree of freedom for signal (DFS), the pressure of maximum sensitivity, reduction rate of error from the a priori error, and the averaging kernel matrix, derived based on the optimal estimation method. The measurement noise levels were assumed to be the same as those for currently available instruments. The weighting functions for the UV, TIR, and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM), and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation (AMATERASU), respectively. The DFS value was increased by approximately 96, 23, and 30 % by adding the MW measurements to the combination of UV and TIR measurements in the UT, MT, and LMT regions, respectively. The MW measurement increased the DFS value of the LMT ozone; nevertheless, the MW measurement alone has no sensitivity to the LMT ozone. The pressure of maximum sensitivity value for the LMT ozone was also increased by adding the MW measurement. These findings indicate that better information on LMT ozone can be obtained by adding constraints on the UT and MT ozone from the MW measurement. The results of this study are applicable to the upcoming air-quality monitoring missions, APOLLO, GMAP-Asia, and uvSCOPE.

Short summary
Air pollution is one of the world's greatest environmental health risks. Ozone adversely affects human health and agricultural production, and the tropospheric ozone has been increasing globally over the past few decades. We report an advanced method to derive the ozone amount in the lowermost troposphere using multi-spectral measurements (UV, thermal infrared and microwave). Combining the MW measurement with the UV and thermal infrared measurements certainly increased the sensitivity.