Spatio-temporal observations of the tertiary ozone maximum

Abstract

Abstract. We present spatio-temporal distributions of the tertiary ozone maximum (TOM), based on GOMOS (Global Ozone Monitoring by Occultation of Stars) ozone measurements in [2002][2003][2004][2005][2006]. The tertiary ozone maximum is typically observed in the high-latitude winter mesosphere at an altitude of ∼72 km. Although the explanation for this phenomenon has been found recently -low concentrations of odd-hydrogen cause the subsequent decrease in odd-oxygen losses -models have had significant deviations from existing observations until recently. Good coverage of polar night regions by GOMOS data has allowed for the first time to obtain spatial and temporal observational distributions of night-time ozone mixing ratio in the mesosphere.The distributions obtained from GOMOS data have specific features, which are variable from year to year. In particular, due to a long lifetime of ozone in polar night conditions, the downward transport of polar air by the meridional circulation is clearly observed in the tertiary ozone maximum time series. Although the maximum tertiary ozone mixing ratio is achieved close to the polar night terminator (as predicted by the theory), TOM can be observed also at very high latitudes, not only in the beginning and at the end, but also in the middle of winter. We have compared the observational spatiotemporal distributions of the tertiary ozone maximum with that obtained using WACCM (Whole Atmosphere Community Climate Model) and found that the specific features are reproduced satisfactorily by the model.Correspondence to: V. F. Sofieva (viktoria.sofieva@fmi.fi) Since ozone in the mesosphere is very sensitive to HO x concentrations, energetic particle precipitation can significantly modify the shape of the ozone profiles. In particular, GOMOS observations have shown that the tertiary ozone maximum was temporarily destroyed during the January 2005 and December 2006 solar proton events as a result of the HO x enhancement from the increased ionization.

Variability of the nighttime OH layer and mesospheric ozone at high latitudes during northern winter: influence of meteorology

“…Because of the longer chemical lifetime of ozone in the middle mesosphere, transport processes become dominant over local photochemistry at the altitude of the TOP. The altitude and abundance variability of the TOP induced by downward transport of polar air was recently discussed by Sofieva et al (2009) and Smith et al (2009) While transport plays an important role at the altitude of the TOP where the nighttime O 3 lifetime is long, chemistry becomes important around 0.01 hPa, where O 3 lifetime is shorter. Ozone increases correspond to the sudden temperature decreases in the MLT during or right after the SSWs.…”

GOMOS O<sub>3</sub>, NO<sub>2</sub>, and NO<sub>3</sub> observations in 2002–2008

“…The polar regions were not investigated as night (or day) measurements alone cannot provide continuous coverage. Studies of GOMOS measurements of O 3 , NO 2 , and NO 3 in the polar regions can be found, for example, in , Seppälä et al (2007), Tétard et al (2009), andSofieva et al (2009). We analysed the daily time series of O 3 , NO 2 , and NO 3 profiles by fitting the series by a time independent constant term, annual and semi-annual terms, a solar proxy and two QBO proxies.…”

Comparison of ozone profiles and influences from the tertiary ozone maximum in the night-to-day ratio above Switzerland

“…The annual variation in the NDR is modulated by oscillations of a planetary timescale (Sonnemann et al, 2007). Sofieva et al (2009) reported that during a sudden stratospheric warming event the tertiary ozone maximum can decrease significantly or can even be completely destroyed. Hocke (2017) has shown the loss of the tertiary ozone layer in the polar mesosphere due to the solar proton event in November 2004.…”

“…Sonnemann et al, 2007;Hartogh et al, 2004) also known as the tertiary ozone maximum (e.g. Sofieva et al, 2009;Degenstein et al, 2005;Marsh et al, 2001). Sonnemann et al (2007) reported that the MMM is a phenomenon that occurs at high latitudes close to the polar night terminator at around 72 km altitude during nighttime in winter and extends into middle latitudes with decreasing amplitude.…”