Statistical Analysis of Total Column Ozone over Uttarakhand: Environment of Himalaya

Total Column Ozone (TCO) is a critical factor affecting the earth’s atmosphere, especially in the Himalayan region. A comprehensive study of TCO trend analysis and corresponding consequences in the Himalayan atmosphere needs to be analyzed. We statistically examine TCO variability by analyzing the daily TCO dataset of the last 15 years (2005–2019) over the crucial region of the Himalayan environment i.e. Uttara-khand, India. Obtained results indicate that TCO values are at peak during the spring season whereas it shows the least value during the winter season. The highest and lowest value of Coefficient of Relative Variance (CRV) is estimated as 3.14 and 1.09 during winter and monsoon season, respectively. Air mass trajectories have been estimated using Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), which shows the existence of strong seasonal variability of Ozone corresponding to continental and maritime transportation towards Uttarakhand. Moreover, Least Square Method (LSM) and the Mann-Kendall test estimate a high correlation (86%) for the seasonal and annual trend of TCO with a negative rate. The obtained decreasing rate is very low which indicates recovery of TCO during the study period. Further results imply that the inter-annual oscillation pattern of TCO is similar to Quasi-Biennial Oscillation (QBO) significantly. In addition, a comparative study has been performed for the data measured by two TCO measuring instruments i.e. Ozone Monitoring Instrument (OMI) and Ozone Mapping Profiler Suite (OMPS). TCO values measured from both instruments are highly correlated (96%) with an average relative difference of around 3%. The outcomes of this study are expected to be beneficial for future study of TCO over other crucial regions of Himalayan territory.