Dr. Shuchita Srivastava |
February 17, 2025 |
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Shuchita Srivastava , Abhinav Sharma and Debashish Mitra
Forest Fire is one of the major emission sources of gaseous air pollutants like carbon monoxide (CO), nitrogen oxides (NOx), volatile organic compounds (VOC) etc. Satellite remote sensing has been instrumental in providing observation of active fire counts and different atmospheric pollutants. Prevailing dry conditions and rainfall deficit during the spring season in North India resulted in widespread, and intense forest fire events in the Himalayan state of Uttarakhand during April 16–30, 2022. Figure 1 shows the time series of VIIRS-detected total fire counts over Uttarakhand for March and April 2022. The noticeable peak of high fire counts suggests that the second half of April 2022 was marked by the intense burning of forests in this hilly state. A comparison of high and nominal confidence fire counts between 2022 and 2021 during 16-30 April shows that fire activity was much stronger in 2022.
The TROPOMI-observed CO and NO2 column concentrations are investigated to understand the influence of this fire event on air quality of Uttrakhand. Investigation showed very high concentration of CO and NO2 over Uttrakhand in 2022 with respect to 2021 during 16-30 April.
Figures 2 and 3 shows the difference of averaged TROPOMI-observed total column density for NO2 and CO between 2022 and 2021 during the study period. The TROPOMI observed total column values of CO and NO2 increased by 9.8% and 11.5% respectively during April 16-30, 2022 with respect to April 16-30, 2021. It is evident from satellite retrieval that an increased concentration of pollutant gases was observed over Uttarakhand for the date range selected for this study.
Figure 1.(a) Total number of VIIRS detected active fire counts over Uttarakhand from March to April 2022 and spatial distribution of active fires from 16 to 30 April (b) 2021 and (c) 2022
Figure 2. Difference of TROPOMI retrieved Total Column Density of NO2 between 16-30 April 2022 and 16-30 April 2021
Figure 3. Difference of TROPOMI retrieved Total Column Density of CO between 16-30 April 2022 and 16-30 April 2021