Solar proton events of October–November 2003: Ozone depletion in the Northern Hemisphere polar winter as seen by GOMOS/Envisat

Abstract

[1] Observations of O 3 and NO 2 made by the GOMOS instrument on board European Space Agency's Envisat satellite have been used to monitor the increase of NO 2 and depletion of ozone due to the solar proton events of October -November 2003. For the first time this phenomenon was measured in polar winter conditions by a satellite instrument. Results show NO 2 enhancement of several hundred per cent and tens of per cent ozone depletion between 36 and 60 km, an effect which lasts several months after the events. A comparison of the afterevent concentrations of NO 2 and ozone reveals a strong negative correlation.

Analysis and parameterisation of ionic reactions affecting middle atmospheric HO<sub>x</sub> and NO<sub>y</sub> during solar proton events

“…Obviously, the significance of ion chemistry causing net production of NO y (or NO x ) and HO x has been known for a long time, and there is observational evidence indicating substantial increase in these neutral species during particle precipitation events (e.g. Seppälä et al, 2004;. Also, the magnitude of the nighttime NO y redistribution by negative ion chemistry is large enough to be detected by satellite-based observations of, for example, HNO 3 (López-Puertas et al, 2005b;Verronen et al, 2011;Funke et al, 2011).…”

“…SPEs and their influence on ozone have played a large role in the research due to the profound impact of SPEs and the availability of ozone observations from several satellite-based instruments McPeters and Jackman, 1985;Reid et al, 1991;Jackman et al, 2001;Seppälä et al, 2004;López-Puertas et al, 2005a;. In recent years, changes in other minor species have received substantial attention after a wealth of satellite observations of the winter polar regions became Published by Copernicus Publications on behalf of the European Geosciences Union.…”

Global ozone monitoring by occultation of stars: an overview of GOMOS measurements on ENVISAT

“…This peak has been attributed by Seppälä et al (2004) and Hauchecorne et al (2006) to the formation of a large amount of NO x during the very intense solar proton event at the end of October 2003. Such NO 2 enhancement after strong solar proton events have been observed and simulated in the past (Jackman et al, 2000(Jackman et al, , 2001Verronen et al, 2002).…”

“…Thanks to its unique night-time capabilities, GOMOS was the first satellite instrument to provide measurements of SPE effects on NO x and ozone in the winter polar regions. For example, Seppälä et al (2004) and Verronen et al (2005b) studied the SPE of October 2003, both the short-term and long-term effects. Shortterm ozone depletion larger than 60% was observed in the mesosphere (65-80 km) while a decrease of ∼40% lasting several months was seen in the upper stratosphere, and these were attributed to the substantial increases of HO x and NO x , respectively.…”

Trends in stratospheric ozone profiles using functional mixed models

“…Even though model flexibility of the AMMs allows complicated fitting of time series, it does not fully capture high and sharp peaks. We believe that the random spikes not accounted for by the regression model correspond to a smaller scale variability that is not captured by proxies, and they can be related to sudden stratospheric warming (Sofieva et al, 2011), wave breaking (Holton, 1983) and other solar high proton events (Seppala et al, 2004) that are not included in the model. There is some information in the upper stratosphere (e.g., 3.9 hPa, Arosa) that is not captured by the regression model.…”