INVESTIGATING THE RELATIONSHIP BETWEEN CHANGES IN ATMOSPHERIC GREENHOUSE GASES AND DISCHARGE FLUCTUATIONS IN THE BASIN OF ARAS RIVER

Abstract

In this study, the relationship between changes in atmospheric greenhouse gases and discharge fluctuations was investigated in the basin of Aras river. To this end, we used two sets of data including greenhouse gases (carbon dioxide, methane and nitrogen oxide) and discharge data in the Aras river basin during a period of 41 years (1968-2009). Furthermore, Pearson correlation, linear and polynomial regression, standard Z scores and Mann-Kendall test were employed. The results of investigating the discharge changes in the basin indicate its monthly and annual decreasing trend. Also, the results of Pearson correlation revealed that the decreasing trend of discharge in the basin has a close relationship with the trend of changes in carbon dioxide and methane. At a confidence level of 99%, except in summer months, almost for all months, there was a negative correlation with discharge of the basin that refers to the decline of discharge in the basin along with the increase of these gases in the environment. The greatest effect of greenhouse gases was observed in the months of December, January, February, March, and April. Mann-Kendall indicated the significance of the change trend in the discharge of the basin. On a monthly or annual basis in all months of the year, this change trend is quite significant.