Seasonal Variation Analysis of Tropospheric O3 and CO over Iraq using AIRS Data During Last Two Decades

Abstract

Ozone (O₃) and carbon monoxide (CO) have both anthropogenic and natural sources and play key roles in the tropospheric oxidation chemistry. The aim of this research is to demonstrate the monthly distributions of tropospheric CO and O₃ and analysed it is long-term during the years 2003–2021. Over Iraq using the Atmospheric inferred sounder (AIRS) data. The monthly CO time series reveled variance changes and fluctuated, minimum (decreases, Jun and September) and maximum (increases, October and April), these seasonal variations depends on topography and meteorological conditions, the total mean value and standard deviation of CO was (1208.6×10^-10 ± 230.8×10-¹⁰ ppmv) during study period. The monthly O₃ time series variance between seasons elevated from January until its peak in May and declined from September to October. These O₃ seasonal variations depend greatly on climate changes, meteorological parameters, and location in the atmosphere, the total mean value and standard deviation of O₃ was (446.4×10^-10 ±76.2×10^-10 ppmv). The monthly CO values variances among the seasons over five considered selected stations; Baghdad, Mosul, Basra, Kirkuk, and Rutba. The highest CO value was on the northern region (Mosul 510×10-10 ppmv) compared with other stations, and the lowest CO value was in the western region (Rutba; 934×10-10 ppmv). For O_3, the highest value was on Mosul (456×10^-10ppmv), and the lowest value was in Basra (431×10^-10 ppmv). The CO results shows negative trends in their annual series over all stations, and the O₃ results shows negative trends at all station except in Basra have significant positive trends