Impact of ENSO on Variability of the Total Ozone Column Over the Northeast Region of Brazil - Part 1: El Niño Canonical and Modoki

Abstract The objective of this work is to analyze the annual variation and the effects of the atmospheric variability mode El Niño (Canonical and Modoki) on the concentration of the Total Ozone Column (TOC) on the NEB between 1997 and 2018 using data generated by the sensors Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI). An average monthly variation was observed, with typical behavior of the annual cycle domain in the seasonal variability, presenting a minimum value in May and maximum in October. There was a declining trend in the series of average values for the entire area. Cluster analysis revealed that different regions of the study area have slightly different behaviors and mean values of the total ozone column. Wavelet analysis was used, which exposed cycles of twelve months in length throughout the studied area, six-month cycles, demonstrating that the semi-annual cycle dominates seasonal variability in lower latitudes, and also two to three years cycles, representing the important performance of the Quasi-Biennial Oscillation (QBO). Anomaly averages show that El Niño events affect TOC causing predominantly a decrease in their values. These Modoki events have a greater potential to affect TOC variations than canonical events, with negative anomalies of greater intensity.

摘要 本研究旨在利用总臭氧测绘光谱仪（Total Ozone Mapping Spectrometer, TOMS）与臭氧监测仪（Ozone Monitoring Instrument, OMI）的观测数据，分析1997—2018年间北赤道带（NEB）内总臭氧柱总量（Total Ozone Column, TOC）的年变化特征，以及大气变率模态厄尔尼诺（经典型与Modoki型）对其浓度的影响。观测到月度平均变化特征，其季节变率符合典型年循环规律，总臭氧柱总量于5月达到极小值，10月达到极大值。整个研究区域的平均数值序列呈现下降趋势。聚类分析结果显示，研究区域内不同子区域的总臭氧柱总量变化特征与平均数值存在小幅差异。本研究采用小波分析方法，揭示了研究区域内普遍存在的12个月周期与6个月周期：其中半年循环在低纬度地区的季节变率中占据主导地位；此外还存在2至3年周期，体现了准两年振荡（Quasi-Biennial Oscillation, QBO）的显著作用。异常平均值分析表明，厄尔尼诺事件会对总臭氧柱总量产生影响，整体表现为其数值下降；其中Modoki型厄尔尼诺事件相较于经典型事件，对总臭氧柱总量变化的影响潜力更强，伴随强度更大的负异常。