Abstract. Atmospheric greenhouse gases (GHGs), such as carbon dioxide (CO 2 ) and methane (CH 4 ), are important climate forcing agents due to their significant impacts on the climate system. The present study brings out first continuous measurements of atmospheric GHGs using highprecision LGR-GGA over Shadnagar, a suburban site of Central India during the year 2014. The annual mean CO 2 and CH 4 over the study region are found to be 394 ± 2.92 and 1.92 ± 0.07 ppm (µ ± 1σ ) respectively. CO 2 and CH 4 show a significant seasonal variation during the study period with maximum (minimum) CO 2 observed during pre-monsoon (monsoon), while CH 4 recorded the maximum during postmonsoon and minimum during monsoon. Irrespective of the seasons, consistent diurnal variations of these gases are observed. Influences of prevailing meteorology (air temperature, wind speed, wind direction, and relative humidity) on GHGs have also been investigated. CO 2 and CH 4 show a strong positive correlation during winter, pre-monsoon, monsoon, and post-monsoon with correlation coefficients (R s ) equal to 0.80, 0.80, 0.61, and 0.72 respectively, indicating a common anthropogenic source for these gases. Analysis of this study reveals the major sources for CO 2 are soil respiration and anthropogenic emissions while vegetation acts as a main sink, whereas the major source and sink for CH 4 are vegetation and presence of hydroxyl (OH) radicals.

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Abstract. Atmospheric greenhouse gases (GHGs) such as carbon dioxide (CO2) and methane (CH4) are important climate forcing agents due to their significant impact on the climate system. The present study brings out first continuous measurements of atmospheric GHG's using high precision Los Gatos Research's-greenhouse gas analyser (LGR-GGA) over Shadnagar, a suburban site of Central India during the period 2014. The annual mean of CO2 and CH4 over the study region is found to be 394 ± 2.92 and 1.92 ± 0.07 ppm (mean, μ ± 1 SD, σ) respectively. CO2 and CH4 showed a significant seasonal variation during the study period with maximum (minimum) CO2 observed during Pre-monsoon (Monsoon), while CH4 recorded maximum during post-monsoon and minimum in monsoon. A consistent diurnal mixing ratio of these gases is observed with high (low) during night (afternoon) hours throughout the study period. Influences of prevailing meteorology (air temperature, wind speed, wind direction and relative humidity) on GHG's have also been investigated. CO2 and CH4 showed a strong positive correlation during winter, pre-monsoon, monsoon and post-monsoon with R equal to 0.80, 0.80, 0.61 and 0.72 respectively. It implies the seasonal variations in source-sink mechanisms of CO2 and CH4. Present study also confirms implicitly the presence OH radicals as a major sink of CH4 over the study region.