About the lab

We work on different atmospheric aspects of atmospheric chemistry and climate connection; including atmospheric pollution and its impact on climate, agriculture and health.

Apart from ground-based and satellite measurements, an ensemble of numerical and statistical models are used for the studies.

Model development and gridded data development for different trace gases are also performed.

Featured projects (1)

This project looks into the changes in tropical cyclone intensity, frequency, precipitation related to cyclones, cold-wakes driven by the cyclones, chlorophyll-a blooms and primary productivity in the oceans, influence of remote connections with cyclone activity such as ENSO, IOD, MJO, and PDO. We also simulate the cyclones with numerical models such as WRF and coupled models.

Featured research (25)

Atmospheric CO2 is the key Greenhouse Gas in terms of its global warming potential and anthropogenic sources. Therefore, it is important to analyse the changes in the concentration of atmospheric CO2 to monitor regional and global climate change. Here, we use ground-based and satellite measurements for the 2002–2020 period to assess CO2 over India. The average CO2 trend over India is about 2.1 ppm/yr, and the highest trends are in agreement with the increase in total energy consumption during the period, and the highest trends are found in the areas of mines and refineries in the west and east India. The estimated CO2 trends for India are comparable to that of global tropical and mid-latitude regions. The increasing CO2 implies serious anthropogenic global warming and thus, calls for mitigation measures and continuous monitoring for timely policy interventions.
India relies heavily on coal-based thermal power plants to meet its energy demands. Sulphur dioxide (SO2) emitted from these plants and industries is a major air pollutant. Analysis of spatial and temporal changes in SO2 using accurate and continuous observations is required to formulate mitigation strategies to curb the increasing air pollution in India. Here, we present the temporal changes in SO2 concentrations over India in the past four decades (1980–2020). Our analysis shows that the Central and East India, and Indo-Gangetic Plain (IGP) are the hotspots of SO2, as these regions house a cluster of thermal power plants, petroleum refineries, steel manufacturing units, and cement Industries. Thermal power plants (51%), and manufacturing and construction industries (29%) are the main sources of anthropogenic SO2 in India. Its concentration over India is higher in winter (December–February) and lower in pre-monsoon (March–May) seasons. The temporal analyses reveal that SO2 concentrations in India increased between 1980 and 2010 due to high coal burning and lack of novel technology to contain the emissions during the period. However, SO2 shows a decreasing trend in recent decade (2010–2020) because of the environmental regulations and implementation of efective control technologies such as the fue gas desulphurisation (FGD) and scrubber. Since 2010, India's renewable energy production has also been increased substantially when India adopted a sustainable development policy. Therefore, the shift in energy production from conventional coal to renewable sources, solid environmental regulation, better inventory, and effective technology would help to curb SO2 pollution in India. Both economic growth and air pollution control can be performed hand-in-hand by adopting new technology to reduce SO2 and GHG emissions.
A nationwide lockdown was imposed in India from 24 March 2020 to 31 May 2020 to contain the spread of COVID-19. The lockdown has changed the atmospheric pollution across the continents. Here, we analyze the changes in two most important air quality related trace gases, nitrogen dioxide (NO2) and tropospheric ozone (O3) from satellite and surface observations, during the lockdown (April–May 2020) and unlock periods (June–September 2020) in India, to examine the baseline emissions when anthropogenic sources were significantly reduced. We use the Bayesian statistics to find the changes in these trace gas concentrations in different time periods. There is a strong reduction in NO2 during the lockdown as public transport and industries were shut during that period. The largest changes are found in IGP (Indo-Gangetic Plain), and industrial and mining areas in Eastern India. The changes are small in the hilly regions, where the concentrations of these trace gases are also very small (0–1 × 10¹⁵ molec./cm²). In addition, a corresponding increase in the concentrations of tropospheric O3 is observed during the period. The analyses over cities show that there is a large decrease in NO2 in Delhi (36%), Bangalore (21%) and Ahmedabad (21%). As the lockdown restrictions were eased during the unlock period, the concentrations of NO2 gradually increased and ozone deceased in most regions. Therefore, this study suggests that pollution control measures should be prioritized, ensuring strict regulations to control the source of anthropogenic pollutants, particularly from the transport and industrial sectors. Highlights • Most cities show a reduction up to 15% of NO2 during the lockdown • The unlock periods show again an increase of about 40–50% in NO2 • An increase in tropospheric O3 is observed together with the decrease in NO2
The increase in greenhouse gases (GHGs) due to anthropogenic activities enhances regional and global temperatures. The most abundant GHG, i.e., water vapour, has a vital positive feedback on the global warming and Earth's climate system. This study focuses on the spatial and temporal changes in water vapour in the troposphere over India and Indian Ocean as derived from the ground-based, satellite and reanalyses data, and assesses the impact on water vapour changes on the regional climate by analysing radiative effects. The analyses show that the annual mean column water vapour (CWV) is high over the northern Indian Ocean, Bay of Bengal and Peninsular India, ranging from 30 to 60 kg/m². Most regions show significant positive trends in the annual mean CWV, about 0.1–0.2 kg/m²/yr. There is a significant positive trend in water vapour in the troposphere (except 200 hPa) over the India land regions, with the highest values at 1000 hPa (0.034 g/kg/yr). The corresponding water vapour radiative effect (WVRE) is about 20–80 W/m², depending on seasons and regions. This study, therefore, indicates that the increase in tropospheric water vapour over India and Indian Ocean could affect the regional temperature and climate.
Arabian Sea (AS) witnessed two very severe cyclones Maha and Kyarr simultaneously in October–November 2019. Here, we analyse the factors that influenced the genesis and simultaneous occurrences of these cyclones. Kyarr (24 October–3 November 2019) is the second super cyclone formed in AS after Gonu in 2007. The path of Maha (30 October–7 November 2019) coincided with that of Kyarr during 1–2 November 2019. The cyclone Maha intensified to an extremely severe cyclone on 4 November 2019, which also encoun- tered a cold core eddy during this period. In general, warmer SST is one of the key factors responsible for the genesis and intensification of cyclones. The co-occurrence of weak El Niño and the positive phase of Indian Ocean Dipole (IOD) during the period increased SST and facilitated the simultaneous occurrence of TCs. In addition, the Madden Julian oscillation Phase 2 and Phase 3 were propagating over the Indian Ocean in this period, which also favoured the cyclogenesis, as these phases lead to enhanced convective activ- ity in maintaining low vertical wind shear and higher mid-tropospheric relative humidity there. Higher oceanic heat content and cyclone heat potential helped the systems to develop and sustain in the higher category stages in the case of Kyarr. The passage of Kyarr cooled SST up to 3.5 °C, but the SST was still higher than 26.5 °C in the region, which provided a suitable environment for the simultaneous occurrence of the cyclone Maha. The positive phase of IOD causes higher than normal SST in AS, which contributes to the cyclone for- mation, and therefore, five cyclones formed in AS in the same year (2019). Henceforth, this study shows the factors responsible for the formation of simultaneous cyclones in AS and is expected to help the analysis and prediction of such extreme weather events.

Lab head

Jayanarayanan Kuttippurath
  • Centre of Oceans, Rivers, Atmosphere and Land Sciences
About Jayanarayanan Kuttippurath
  • I work with atmospheric observations and numerical models to unravel the connection between the atmospheric composition and climate change.

Members (17)

Sarath Raj
  • Indian Institute of Technology Kharagpur
Surajit Murasingh
  • Indian Institute of Technology Kharagpur
Pankaj Kumar
  • Indian Institute of Technology Kharagpur
Sunanda Narayanan
  • Indian Institute of Technology Kharagpur
Rahul Kashyap
  • Indian Institute of Technology Kharagpur
Ajay Singh
  • Indian Institute of Technology Kharagpur
Akhila R S
  • Indian Institute of Technology Kharagpur

Alumni (9)

Anandh Ts
  • Indian Institute of Technology Kharagpur
Raina Roy
Chetan Naik
  • Indian Institute of Technology Kharagpur
Tanya Patel
  • Indian Institute of Technology Kharagpur