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）与臭氧监测仪器（Ozone Monitoring Instrument, OMI）获取的观测数据，分析1997-2018年间NEB区域内两类大气变率模态厄尔尼诺（典型型与模态型）对总臭氧柱（Total Ozone Column, TOC）浓度的影响及其年际变化特征。研究观测到显著的月均变化特征，季节变率呈现典型的年循环模态，总臭氧柱浓度于5月达到极小值，10月达到极大值。整个研究区域的总臭氧柱平均浓度序列呈下降趋势。聚类分析结果显示，研究区内不同区域的总臭氧柱浓度变化特征与平均水平存在细微差异。本研究采用小波分析方法，结果揭示研究全域均存在12个月周期信号，同时存在6个月周期信号，表明低纬度地区的季节变率以半年循环为主；此外还识别出2-3年周期信号，对应准两年振荡（Quasi-Biennial Oscillation, QBO）的显著活动特征。距平平均结果显示，厄尔尼诺事件会对总臭氧柱浓度产生影响，整体表现为浓度降低；相较于典型型厄尔尼诺事件，模态型厄尔尼诺事件对总臭氧柱浓度变化的影响潜力更强，对应的负距平强度也更高。