First observation of tropospheric nitrogen dioxide from the Environmental Trace Gases Monitoring Instrument onboard the GaoFen-5 satellite

Chengxin Zhang; Cheng Liu; Ka Lok Chan; Qihou Hu; Haoran Liu; Bo Li; Chengzhi Xing; Wei Tan; Haijin Zhou; Fuqi Si; Jianguo Liu

doi:10.1038/s41377-020-0306-z

First observation of tropospheric nitrogen dioxide from the Environmental Trace Gases Monitoring Instrument onboard the GaoFen-5 satellite

Light Sci Appl. 2020 Apr 20:9:66. doi: 10.1038/s41377-020-0306-z. eCollection 2020.

Authors

Chengxin Zhang^#¹, Cheng Liu^#^{2

3

4

5}, Ka Lok Chan⁶, Qihou Hu³, Haoran Liu¹, Bo Li¹, Chengzhi Xing¹, Wei Tan³, Haijin Zhou³, Fuqi Si³, Jianguo Liu^{3

4}

Affiliations

¹ 1School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026 China.
² 2Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230026 China.
³ 3Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, 230031 China.
⁴ 4Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China.
⁵ 5Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, 230026 China.
⁶ 6Remote Sensing Technology Institute (IMF), German Aerospace Center (DLR), Oberpfaffenhofen, Germany.

^# Contributed equally.

Abstract

The Environmental Trace Gases Monitoring Instrument (EMI) is the first Chinese satellite-borne UV-Vis spectrometer aiming to measure the distribution of atmospheric trace gases on a global scale. The EMI instrument onboard the GaoFen-5 satellite was launched on 9 May 2018. In this paper, we present the tropospheric nitrogen dioxide (NO₂) vertical column density (VCD) retrieval algorithm dedicated to EMI measurement. We report the first successful retrieval of tropospheric NO₂ VCD from the EMI instrument. Our retrieval improved the original EMI NO₂ prototype algorithm by modifying the settings of the spectral fit and air mass factor calculations to account for the on-orbit instrumental performance changes. The retrieved EMI NO₂ VCDs generally show good spatiotemporal agreement with the satellite-borne Ozone Monitoring Instrument and TROPOspheric Monitoring Instrument (correlation coefficient R of ~0.9, bias < 50%). A comparison with ground-based MAX-DOAS (Multi-Axis Differential Optical Absorption Spectroscopy) observations also shows good correlation with an R of 0.82. The results indicate that the EMI NO₂ retrieval algorithm derives reliable and precise results, and this algorithm can feasibly produce stable operational products that can contribute to global air pollution monitoring.

Keywords: Atmospheric optics; Optical spectroscopy.

Grants and funding

NO. 41722501, 91544212, 51778596, AND 41575021/National Science Foundation of China | National Natural Science Foundation of China-Yunnan Joint Fund (NSFC-Yunnan Joint Fund)