Comparative multifractal analysis of methane gas concentration time series in India and regions within India

In the present study GOSAT CH4 has been used to analyze the methane gas concentration in India over the eight years from 2010 to 2017. The data have been analyzed using the multifractal detrended fluctuation analysis technique. Two different geographical regions within India have been selected and CH4 data for those regions are also analyzed. The generalized Hurst exponents for India and the two regions are 1.27, 0.74 and 0.91, which are significantly high from their shuffled data counterparts i.e. 0.50, 0.51 and 0.51 respectively. This finding reveals that methane gas concentration over time show multifractal nature which in turn establishes the presence of long-range temporal correlations in the data. The width of the Multifractal spectrum for India and the two regions are found to be 0.76, 1.38 and 1.01 respectively. This result shows that strength of correlation is different for the two regions selected, which we suggest may be due to the different methane emission process of the considered regions. Comparison of the results with that of shuffled data signify that the correlation is purely due to the methane production dynamics and not a result of mere statistics.