El Niño―Southern Oscillation in Tropical and Midlatitude Column Ozone

• Published in: Journal of the atmospheric sciences 2011-09, Vol.68 (9), p.1911-1921
• Main Authors: WANG, Jingqian, PAWSON, Steven, BAIJUN TIAN, LIANG, Mao-Chang, SHIA, Run-Lie, YUNG, Yuk L, XUN JIANG
• Format: Article
• Language: English
• Subjects: Atmospheric chemistry; Boundary conditions; Climate models; Comparative analysis; Datasets; Earth, ocean, space; Eigenvalues; El Nino; El Nino phenomena; El Nino-Southern Oscillation event; Exact sciences and technology; External geophysics; General circulation models; Greenhouse gases; Ground stations; Latitude; Meteorology; Modelling; Ozone; Physics of the high neutral atmosphere; Pressure; Principal components analysis; Quasi-biennial oscillation; Regression coefficients; Regression models; Sea ice; Sea ice temperatures; Sea surface; Sea surface temperature; Simulation; Solar cycle; Solar oscillations; Southern Oscillation; Statistical significance; Stratosphere; Studies; Surface temperature; Time series; Total Ozone Mapping Spectrometer; Tropical tropopause; Tropopause
• ISSN: 0022-4928; 1520-0469
• DOI: 10.1175/JAS-D-11-045.1

The impacts of El Niño–Southern Oscillation (ENSO) on the tropical total column ozone, the tropical tropopause pressure, and the 3.5-yr ozone signal in the midlatitude total column ozone were examined using the Goddard Earth Observing System Chemistry–Climate Model (GEOS CCM). Observed monthly mean sea surface temperature and sea ice between 1951 and 2004 were used as boundary conditions for the model. Since the model includes no solar cycle, quasi-biennial oscillation, or volcanic forcing, the ENSO signal was found to dominate the tropical total column ozone variability. Principal component analysis was applied to the detrended, deseasonalized, and low-pass filtered model outputs. The first mode of model total column ozone captured 63.8% of the total variance. The spatial pattern of this mode was similar to that in Total Ozone Mapping Spectrometer (TOMS) observations. There was also a clear ENSO signal in the tropical tropopause pressure in the GEOS CCM, which is related to the ENSO signal in the total column ozone. The regression coefficient between the model total column ozone and the model tropopause pressure was 0.71 Dobson units (DU) hPa−1. The GEOS CCM was also used to investigate a possible mechanism for the 3.5-yr signal observed in the midlatitude total column ozone. The 3.5-yr signal in the GEOS CCM column ozone is similar to that in the observations, which suggests that a model with realistic ENSO can reproduce the 3.5-yr signal. Hence, it is likely that the 3.5-yr signal was caused by ENSO.