著者

Kaho NITTA Prakhar MISRA Sachiko HAYASHIDA

出版者

The Remote Sensing Society of Japan

雑誌

日本リモートセンシング学会誌 (ISSN:02897911)

巻号頁・発行日

vol.42, no.1, pp.36-50, 2022-02-10 (Released:2022-04-26)

参考文献数

36

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In this study, the advantage of the state-of-the-art sensor TROPOspheric Monitoring Instrument (TROPOMI) for air pollution research in Indian subcontinent is examined by comparing it with the conventional sensor Ozone Monitoring Instrument (OMI), which has been utilized for more than 15 years since its launch in 2004. The OMI nitrogen dioxide (NO2) dataset was used for comparison, namely, version 4.0 of the standard product developed by NASA (named OMNO2). As our focus is the application of satellite sensors to the study of air pollution, only the areas with high NO2 concentration were extracted for the analysis. A one-year comparison between July 2018 and June 2019 showed strong positive correlation between TROPOMI and the OMI product, with Pearson correlation coefficient of 0.76. The difference between OMI and TROPOMI was generally random. Compared with OMNO2 version 4.0, the annually averaged difference of TROPOMI was found to be (−0.8±1.1)×1015 (1σ) molecules cm−2, which is −22 %±24 % (1σ) as a relative value. The good agreement between TROPOMI and OMI confirmed the compatibility of the observed values. The high resolution of TROPOMI enables the observation of small-scale sources of NO2 that cannot be detected by OMI, which allowed the identification of some examples of NO2 hotspots over power plants in India. The recent identification of a rapid decrease in NO2 after the COVID-19 lockdown in March 2020 in India using TROPOMI data demonstrates the potential of this sensor to detect rapid changes in anthropogenic activities. Our analysis demonstrates usefulness of the NO2 data from TROPOMI, and fruitful scientific results are expected in the future.