Influence of meteorological parameters on atmospheric CO₂ at Bharati, the Indian Antarctic research station

ABSTRACT

During the 35th Indian Scientific Expedition to Antarctica, measurements of atmospheric carbon dioxide (CO₂) were carried out using a Li-Cor CO₂/H₂O analyser at Bharati, the Indian Antarctic research station. This study examines the short-term variability of atmospheric CO₂ during the austral summer (January–February) of 2016. An average of 396.25 ± 4.20 ppm was observed during the study period. Meteorological parameters such as relative humidity, precipitation, wind speed, air temperature and atmospheric boundary layer height in conjunction with photosynthetically active radiation, the biological activity indicator which modulates atmospheric CO₂ concentration have been investigated. High wind speed (>20 m s⁻¹) combined with precipitation scavenges CO₂ in the atmosphere, resulting in low concentrations at the study site. The lowest CO₂ concentration of 385 ppm coincided with heavy precipitation of 15 mm during study period. Statistical analysis of the data shows that precipitation and relative humidity independently correlated 55% (r = −0.55) and 32% (r = −0.32), respectively, with the variability of CO₂ mixing in the atmosphere at the study site. Atmospheric CO₂ was significantly correlated with precipitation alone with a p value of 0.003. Further, multiple regression analysis was performed to test the significant relation between variability of atmospheric CO₂ and meteorological parameters. Long-range air-mass transport analysis depicted that the majority of the air masses are reaching the study site through the oceanic region.

KEYWORDS:

• Carbon dioxide
• Li-Cor CO₂/H₂O analyser
• precipitation
• relative humidity
• wind speed
• long-range air-mass transport

ABBREVIATIONS:

• AT: air temperature
• BLH: atmospheric boundary layer height
• CH₄: methane
• CO₂: carbon dioxide
• H₂O: water vapour
• NRSC: National Remote Sensing Centre
• PAR: photosynthetically active radiation
• RH: relative humidity
• WS: wind speed

Acknowledgements

We thank the Director of the NRSC, Dr Y.V.N. Krishna Murthy, for supporting the continuation of polar science research at NRSC. We also thank Dr M.V.R. Sesha Sai, Deputy Director of the Earth and Climate Science Area, for his support. The authors sincerely thank the Programme Directors of Logistics and Science at the National Centre for Antarctic and Ocean Research, Goa, and voyage leader Dr Shailendra Saini and Mr Brijesh Desai, both at the same institution, for their support of the data collection. We also gratefully acknowledge the India Meteorological Department for sharing the meteorological data from the study site. We thank Dr Matthew A. Lazzara, Associate Scientist/Meteorologist at Antarctic Meteorological Research Center, for providing the information about radiosonde data collected at McMurdo Station. We also sincerely thank the Subject Editor and anonymous referees for their constructive comments and suggestions, which have certainly helped to improve the quality of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was carried out as part of Atmospheric CO₂ Retrieval and Monitoring of the National Carbon Project, under the umbrella of Climate and Atmospheric Processes of Indian Space Research Organization’s Geosphere–Biosphere Program.