Further studies on possible volcanic signal to the ozone layer

Zerefos, C. S.; Tourpali, Kleareti; Bais, A. F.

doi:10.1029/94jd02142

Cited by 56 publications

(22 citation statements)

References 28 publications

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“…The PC1 values are negative after these two events, which suggests the occurrence of ozone depletion after the volcano eruptions in the NH. These results are consistent with the results of Zerefos et al (1994) and Coffey (1996). The power spectrum of the detrended PC1 (Fig.…”

Section: A Results For Northern Hemispheric Column Osupporting

confidence: 82%

Interannual Variability and Trends of Extratropical Ozone. Part I: Northern Hemisphere

et al. 2008

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The authors apply principal component analysis (PCA) to the extratropical total column ozone from the combined merged ozone data product and the European Centre for Medium-Range Weather Forecasts assimilated ozone from January 1979 to August 2002. The interannual variability (IAV) of extratropical O 3 in the Northern Hemisphere (NH) is characterized by four main modes. Attributable to dominant dynamical effects, these four modes account for nearly 60% of the total ozone variance in the NH. The patterns of variability are distinctly different from those derived for total O 3 in the tropics. To relate the derived patterns of O 3 to atmospheric dynamics, similar decompositions are performed for the 30-100-hPa geopotential thickness. The results reveal intimate connections between the IAV of total ozone and the atmospheric circulation.The first two leading modes are nearly zonally symmetric and represent the connections to the annular modes and the quasi-biennial oscillation. The other two modes exhibit in-quadrature, wavenumber-1 structures that, when combined, describe the displacement of the polar vortices in response to planetary waves. In the NH, the extrema of these combined modes have preferred locations that suggest fixed topographical and land-sea thermal forcing of the involved planetary waves. Similar spatial patterns and trends in extratropical column ozone are simulated by the Goddard Earth Observation System chemistry-climate model (GEOS-CCM).The decreasing O 3 trend is captured in the first mode. The largest trend occurs at the North Pole, with values ϳϪ1 Dobson Unit (DU) yr Ϫ1. There is almost no trend in tropical O 3 . The trends derived from PCA are confirmed using a completely independent method, empirical mode decomposition, for zonally averaged O 3 data. The O 3 trend is also captured by mode 1 in the GEOS-CCM, but the decrease is substantially larger than that in the real atmosphere.

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Section: A Results For Northern Hemispheric Column Osupporting

confidence: 82%

Interannual Variability and Trends of Extratropical Ozone. Part I: Northern Hemisphere

et al. 2008

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“…The El Chichón aerosols remained mostly north of the equator, so there was less ozone depletion in the SH (Pollack et al 1983;Zerefos et al 1994). Although considerable amount of Pinatubo aerosols moved to the SH midlatitude (Trepte et al 1993), the ozone depletion signal is very small (Zerefos et al 1994;Coffey 1996) and may be embedded in the large natural variability. The spectral estimate of the detrended PC2 reveals significant peaks at the residual annual cycle (A) and at 3032 around 20 (Q 1 ), 28 (Q), and 9 months.…”

Section: A Results For Southern Hemispheric Column Omentioning

confidence: 99%

Interannual Variability and Trends of Extratropical Ozone. Part II: Southern Hemisphere

et al. 2008

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A principal component analysis (PCA) is applied to the Southern Hemisphere (SH) total column ozone following the method established for analyzing the data in the Northern Hemisphere (NH) in a companion paper. The interannual variability (IAV) of extratropical O 3 in the SH is characterized by four main modes, which account for 75% of the total variance. The first two leading modes are approximately zonally symmetric and relate to the Southern Hemisphere annular mode and the quasi-biennial oscillation. The third and fourth modes exhibit wavenumber-1 structures. Contrary to the Northern Hemisphere, the third and fourth modes are not related to stationary waves. Similar results are obtained for the 30-100-hPa geopotential thickness. The decreasing O 3 trend in the SH is captured in the first mode. The largest trend is at the South Pole, with value ϳϪ2 Dobson Units (DU) yr Ϫ1. Both the spatial pattern and trends in the column ozone are captured by the Goddard Earth Observation System chemistry-climate model (GEOS-CCM) in the SH.

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“…Total ozone at 40 • N presents a phase-shift of almost eight months relative to the 30 hPa equatorial stratospheric zonal wind (e.g. Zerefos et al, 1994Zerefos et al, , 1998. The relation between the 30 hPa stratospheric equatorial zonal winds with both total ozone and spectral solar irradiance at 305 nm is shown in Fig.…”

Section: The Qbomentioning

confidence: 99%

A note on the interannual variations of UV-B erythemal doses and solar irradiance from ground-based and satellite observations

et al. 2001

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Abstract. This study examines three UV-B data sets: groundbased long-term spectral records at Thessaloniki, Greece (40.5 • N, 22.9 • E) and San Diego, California, USA (32.7 • N, 117.2 • W) as well as a global data set of daily erythemal dose obtained from the Total Ozone Mapping Spectrometer (TOMS) onboard the Nimbus-7 satellite. Both ground-based stations have long enough records of spectral UV-B measurements to allow independent time series analyses. For 63 • solar zenith angle (SZA) and clear sky conditions the quasi biennial oscillation (QBO) effect in solar irradiance at 305nm E 305 is about 32% of the annual cycle for both San Diego and Thessaloniki. The effect slightly increases with cloud cover of up to 4/8, and decreases thereafter for cloud cover greater than 4/8. The data reveal that cloudiness cannot offset interannual signals in UV-B records. The observations at San Diego provide an independent confirmation of the widespread nature of the QBO in UV-B, which about coincides in amplitude at the two station studies, both located in the latitude zone 30 • -40 • N. The peak-to-peak amplitude of the QBO in erythemal dose derived from TOMS/Nimbus-7 data is 6.5% at Thessaloniki. This is similar to the values calculated from ground-based measurements from this station. Based on satellite data, we find that the amplitude of the QBO in the erythemal dose is almost 40% of the amplitude of the annual cycle only in the tropics. The ratio of the amplitudes of the QBO over the annual cycle in erythemal dose decreases towards the extratropics, becoming less than 5% over middle latitudes.

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Further studies on possible volcanic signal to the ozone layer

Cited by 56 publications

References 28 publications

Interannual Variability and Trends of Extratropical Ozone. Part I: Northern Hemisphere

Interannual Variability and Trends of Extratropical Ozone. Part I: Northern Hemisphere

Interannual Variability and Trends of Extratropical Ozone. Part II: Southern Hemisphere

A note on the interannual variations of UV-B erythemal doses and solar irradiance from ground-based and satellite observations

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