A Linkage Between Aerosol Optical Depth (AOD) and Meteorological Drought over the Eastern Gangetic Plain of India

2021 ◽  
Author(s):  
P. Parth Sarthi ◽  
Sunny Kumar ◽  
Archisman Barat
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Meteorological Drought ◽  
Gangetic Plain

scholarly journals Impact of Shutdown due to COVID-19 Pandemic on Aerosol Characteristics in Kanpur, India

2020 ◽  
Vol 10 (28) ◽  
Author(s):  
Nidhi Shukla ◽  
Gautam Kumar Sharma ◽  
Parinita Baruah ◽  
V. K. Shukla ◽  
Prashant Gargava
Keyword(s):  
Air Pollution ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Action Plan ◽  
Anthropogenic Emissions ◽  
Industrial Emissions ◽  
Gangetic Plain ◽  
Aerosol Loading ◽  
Time Periods ◽  
The Impact

Background Since March 2020, the number of confirmed COVID-19 positive cases have steadily risen in India. Various preventive measures have been taken to contain the spread of COVID-19. With restrictions on human activities, anthropogenic emissions driving air pollution levels have seen a reduction since March 23, 2020, when the government imposed the first nationwide shutdown. The landlocked Indo-Gangetic Plain (IGP) has many densely-populated cities, witnessing high levels of particulate matter due to both nature-driven and anthropogenic elements. Kanpur is an urban metropolis in the IGP with high aerosol loading, and this paper explores the impact of restricted anthropogenic activities on aerosol characteristics in Kanpur. Objectives This study aims to investigate the change in aerosol optical depth level and its related parameters during the shutdown phases in Kanpur city compared to the same time periods in 2017–2019. Methods Aerosol optical properties such as aerosol optical depth (AOD) at 500 nm, Angstrom exponent (AE), fine mode fraction (FMF) of AOD at 500 nm and single scattering albedo (SSA) at 440 nm were obtained from the Aerosol Robotic Network (AERONET) station operating in Kanpur from the 1st March to the 30th April for 2017–2020. Results A significant decrease in aerosol loading was observed during the shutdown period compared to the pre-and partial shutdown periods in 2020 as well as during the same time periods of 2017–2019. Mean AOD, FMF and SSA were 0.37, 0.43 and 0.89, respectively, during the shutdown period in 2020. A 20–35% reduction in mean AOD levels was observed during the shutdown period in 2020 as compared to the same period in 2017–2019. Conclusions The shutdown led to an improvement in air quality due to decreases in anthropogenic emissions. As fine particles, typically from urban and industrial emissions, dominate episodic air pollution events, this study can be further utilized by the scientific community and regulators to strengthen the emergency response action plan to check high pollution episodes in Kanpur city until cleaner technologies are in place. Competing Interests The authors declare no completing financial interests.

scholarly journals Spectral analysis of aerosol optical depth over aeronet sites of Nepal

BIBECHANA ◽  
2020 ◽  
Vol 17 ◽  
pp. 80-88
Author(s):  
Aashma Acharya ◽  
Binod Adhikari ◽  
Pratik Bhattarai ◽  
Gopal Jha ◽  
Shambhu Acharya ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Suspended Particle ◽  
Spatial And Temporal Variation ◽  
Gangetic Plain ◽  
Global Circulation ◽  
Aerosol Loading ◽  
Himalayan Foothills

The suspended particle aerosols especially anthropogenic are recognized to have degradation in the quality of the atmosphere and one of the factors to cause uncertainty in climate. In this paper, we have investigated the trend of the parameter ‘Aerosol Optical depth’ and by application of spectral based wavelet analysis; we extracted spatial and temporal variation over the selected AERONET sites of Nepal. We have taken the site Kyanjin_gompa, Lumbini, Pokhara and Kathmandu under the consideration of our study because of their geographical variability which is a significant factor for causing variation in local as well as global circulation of aerosols. As per data retrieved from Ground-Based remote sensing system for the year 2018 over the site Kyanjin gompa, Lumbini and Pokhara and for the year 2016 over the Kathmandu, we extracted the periodicity and frequency of the variation in AOD for each site by the application of continuous wavelet analysis on AOD at three different wavelengths. On reviewing the previous studies, it is seen that the area lying at the Indo-Gangetic plain exhibit high aerosol loading in comparison with the Himalayan foothills and central Himalayas of Nepal. We found not only the higher aerosol loading in atmosphere over site Lumbini but also higher periodicity. Likewise, we also found Pokhara as highly polluted as Lumbini. The investigation of data records over the site Kathmandu has shown increment in aerosol loading in the year 2016 compared with previous years. BIBECHANA 17 (2020) 80-88

scholarly journals Amplification of South Asian haze by water vapour–aerosol interactions

2020 ◽  
Vol 20 (22) ◽  
pp. 14457-14471
Author(s):  
Vijayakumar Sivadasan Nair ◽  
Filippo Giorgi ◽  
Usha Keshav Hasyagar
Keyword(s):  
Boundary Layer ◽  
Air Quality ◽  
South Asia ◽  
Water Vapour ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Climate Model ◽  
Mitigation Strategies ◽  
Surface Cooling ◽  
Gangetic Plain

Abstract. Air pollution and wintertime fog over South Asia is a major concern due to its significant implications for air quality, visibility and health. Using a regional climate model coupled with chemistry, we assess the contribution of the hygroscopic growth of aerosols (ambient–dry) to the total aerosol optical depth and demonstrate that the increased surface cooling due to the hygroscopic effects of aerosols further increases the humidity in the boundary layer and thus enhances the confinement of pollutants through aerosol–boundary layer interactions. This positive feedback mechanism plays an important role in the prevalence of wintertime fog and poor air quality conditions over South Asia, where water vapour contributes more than half of the aerosol optical depth. The aerosol–boundary layer interactions lead to moistening of the boundary layer and drying of the free troposphere, which amplifies the long-term trend in relative humidity over the Indo-Gangetic Plain during winter. Hence, the aerosol–water vapour interaction plays a decisive role in the formation and maintenance of the wintertime fog conditions over South Asia, which needs to be considered for planning mitigation strategies.

scholarly journals Amplification of South Asian haze by water vapour-aerosol interactions

2020 ◽  
Author(s):  
Vijayakumar Sivadasan Nair ◽  
Filippo Giorgi ◽  
Usha Keshav Hasyagar
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Air Quality ◽  
South Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Climate Model ◽  
Mitigation Strategies ◽  
Surface Cooling ◽  
Gangetic Plain

Abstract. Air pollution and wintertime fog over South Asia is a major concern due to its significant implications on air quality, visibility and health. Using a coupled regional climate model with on-line chemistry, we assess the contribution of the hygroscopic growth of aerosols (wet-dry) to the total aerosol optical depth and demonstrate that the increased surface cooling due to the hygroscopic effects of aerosols further increases the humidity in the boundary layer and thus enhances the confinement of pollutants through aerosol-boundary layer interactions. This positive feedback mechanism plays an important role in the prevalence of wintertime fog and low air quality conditions over South Asia, where water vapor contributes more than half of the aerosol optical depth. The aerosol-boundary layer interactions lead to the moistening of the boundary layer and drying of the free-troposphere, which amplifies the long-term trend in relative humidity over the Indo-Gangetic Plain during winter. Hence, the aerosol-water vapor interaction plays a decisive role in the formation and maintenance of the wintertime thick fog conditions over South Asia, which needs to be considered for planning mitigation strategies.

The Impact of Dust Storms on Aerosol Optical Depth and Radiative Forcing

2020 ◽  
Vol 16 (1) ◽  
pp. 1-14
Author(s):  
Monim Jiboori ◽  
Nadia Abed ◽  
Mohamed Abdel Wahab
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Dust Storms ◽  
The Impact

Aerosol optical depth at ALOMAR Observatory (Andøya, Norway) in summer 2002 and 2003

Tellus B ◽  
2006 ◽  
Vol 58 (3) ◽  
Author(s):  
Carlos Toledano ◽  
Victoria Cachorro ◽  
Alberto Berjón ◽  
Mar Sorribas ◽  
Ricardo Vergaz ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth

Impact of aerosol on air temperature in Baghdad

2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Yaseen Kadhim Abbas Al-Timimi ◽  
Ali Challob Khraibet
Keyword(s):  
Temperature Variation ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Air Temperature ◽  
Strong Correlation ◽  
Imaging Spectrometer ◽  
Moderate Resolution ◽  
Resolution Imaging

Aerosol Optical Depth (AOD) is the measure of aerosol distributed with a Column of air from earth’s surface to the top of atmosphere, in this study, temperature variation of aerosol optical depth (AOD) in Baghdad was analyzed Moderate Resolution Imaging Spectrometer (MODIS) from Terra and its relationship with temperature for the period 2003 – 2015 were examined. The highest values for mean seasonal AOD were observed in spring and summer and the maximum AOD values ranged from 0.50 to 0.58 by contrast minimum AOD values ranging from 0.30 to 0.41 were found in winter and autumn. Results of study also showed that the temperature (max., min., mean air temperature and DTR) have a strong correlation with AOD (0.82, 0.83, 0.82 and 0.65) respectively.

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