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Missing driver in the Sun-Earth connection from energetic electron precipitation impacts mesospheric ozone.

Andersson ME, Verronen PT, Rodger CJ, Clilverd MA, Seppälä A - Nat Commun (2014)

Bottom Line: However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date.On solar cycle timescales, we find that EEP causes ozone variations of up to 34% at 70-80 km.With such a magnitude, it is reasonable to suspect that EEP could be an important part of solar influence on the atmosphere and climate system.

View Article: PubMed Central - PubMed

Affiliation: Earth Observation, Finnish Meteorological Institute, PO Box 503 (Erik Palménin aukio 1), Helsinki FI-00101, Finland.

ABSTRACT
Energetic electron precipitation (EEP) from the Earth's outer radiation belt continuously affects the chemical composition of the polar mesosphere. EEP can contribute to catalytic ozone loss in the mesosphere through ionization and enhanced production of odd hydrogen. However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date. Here we show, using observations from three different satellite instruments, that EEP events strongly affect ozone at 60-80 km, leading to extremely large (up to 90%) short-term ozone depletion. This impact is comparable to that of large, but much less frequent, solar proton events. On solar cycle timescales, we find that EEP causes ozone variations of up to 34% at 70-80 km. With such a magnitude, it is reasonable to suspect that EEP could be an important part of solar influence on the atmosphere and climate system.

No MeSH data available.


Related in: MedlinePlus

Magnitude of the short-term EEP effects on mesospheric ozone.(a–c) O3 anomalies (%) for selected EEP events in the Northern hemisphere and in the Southern hemisphere derived from GOMOS (a), SABER (b) and MLS (c) observations. Black dashed lines: EEP event start end end; red dashed lines: SPE event start end end; black numbers: daily mean ECRs; red numbers: >10 MeV pfu. (d–i) Superposed epoch analysis for EEP events with daily ECR >150 (counts s−1) showing ozone anomalies (%) and ECR (black lines) in the Northern hemisphere (d,f,h) and in the Southern hemisphere (e,g,i). White numbers: O3 loss at different altitudes.
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f2: Magnitude of the short-term EEP effects on mesospheric ozone.(a–c) O3 anomalies (%) for selected EEP events in the Northern hemisphere and in the Southern hemisphere derived from GOMOS (a), SABER (b) and MLS (c) observations. Black dashed lines: EEP event start end end; red dashed lines: SPE event start end end; black numbers: daily mean ECRs; red numbers: >10 MeV pfu. (d–i) Superposed epoch analysis for EEP events with daily ECR >150 (counts s−1) showing ozone anomalies (%) and ECR (black lines) in the Northern hemisphere (d,f,h) and in the Southern hemisphere (e,g,i). White numbers: O3 loss at different altitudes.

Mentions: The response of mesospheric ozone to EEP is immediate; however, the magnitude and duration of the depletion can differ depending on both the characteristics of the event as well as the season (Fig. 2a–c). During strong EEP events lasting more than 5 days, for example, 03/2003, 11/2003 and 01/2005, significant ozone depletion of up to 90% is seen at altitudes 75–80 km, with the impact reaching down to 60 km altitude. Over the 60- to 80-km altitude range, these events are comparable to the effects of large SPEs. Shorter EEP events (1–5 days, Supplementary Fig. 1a,b) usually affect altitudes between 65 and 80 km with maximum O3 decreases of 70%. The effect of EEP is typically more pronounced during the wintertime (Fig. 2a, Supplementary Fig. 1b), as the EEP-HOx production is then relatively larger when compared with the background HOx production by photodissociation of water vapour. Of the 60 EEP events, the one on 9–23 November 2003 caused the strongest ozone depletion (Fig. 2a). The event lasted 15 days, with major forcing on 10 of those days and occurred right after Halloween 2003 SPE event. This EEP event had ozone depleted by maximum of 92%, a day after the strongest EEP forcing on 11 November. Although in principle the ozone depletion caused by the Halloween SPE could influence the EEP event period, the GOMOS observations (Fig. 2a) as well as observations at higher latitudes from the MIPAS and SCIAMACHY instruments789 show that, in agreement with modelling, the mesospheric ozone recovered from the effects of the SPE event by 7–8 November, before the strong EEP forcing is observed.


Missing driver in the Sun-Earth connection from energetic electron precipitation impacts mesospheric ozone.

Andersson ME, Verronen PT, Rodger CJ, Clilverd MA, Seppälä A - Nat Commun (2014)

Magnitude of the short-term EEP effects on mesospheric ozone.(a–c) O3 anomalies (%) for selected EEP events in the Northern hemisphere and in the Southern hemisphere derived from GOMOS (a), SABER (b) and MLS (c) observations. Black dashed lines: EEP event start end end; red dashed lines: SPE event start end end; black numbers: daily mean ECRs; red numbers: >10 MeV pfu. (d–i) Superposed epoch analysis for EEP events with daily ECR >150 (counts s−1) showing ozone anomalies (%) and ECR (black lines) in the Northern hemisphere (d,f,h) and in the Southern hemisphere (e,g,i). White numbers: O3 loss at different altitudes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214406&req=5

f2: Magnitude of the short-term EEP effects on mesospheric ozone.(a–c) O3 anomalies (%) for selected EEP events in the Northern hemisphere and in the Southern hemisphere derived from GOMOS (a), SABER (b) and MLS (c) observations. Black dashed lines: EEP event start end end; red dashed lines: SPE event start end end; black numbers: daily mean ECRs; red numbers: >10 MeV pfu. (d–i) Superposed epoch analysis for EEP events with daily ECR >150 (counts s−1) showing ozone anomalies (%) and ECR (black lines) in the Northern hemisphere (d,f,h) and in the Southern hemisphere (e,g,i). White numbers: O3 loss at different altitudes.
Mentions: The response of mesospheric ozone to EEP is immediate; however, the magnitude and duration of the depletion can differ depending on both the characteristics of the event as well as the season (Fig. 2a–c). During strong EEP events lasting more than 5 days, for example, 03/2003, 11/2003 and 01/2005, significant ozone depletion of up to 90% is seen at altitudes 75–80 km, with the impact reaching down to 60 km altitude. Over the 60- to 80-km altitude range, these events are comparable to the effects of large SPEs. Shorter EEP events (1–5 days, Supplementary Fig. 1a,b) usually affect altitudes between 65 and 80 km with maximum O3 decreases of 70%. The effect of EEP is typically more pronounced during the wintertime (Fig. 2a, Supplementary Fig. 1b), as the EEP-HOx production is then relatively larger when compared with the background HOx production by photodissociation of water vapour. Of the 60 EEP events, the one on 9–23 November 2003 caused the strongest ozone depletion (Fig. 2a). The event lasted 15 days, with major forcing on 10 of those days and occurred right after Halloween 2003 SPE event. This EEP event had ozone depleted by maximum of 92%, a day after the strongest EEP forcing on 11 November. Although in principle the ozone depletion caused by the Halloween SPE could influence the EEP event period, the GOMOS observations (Fig. 2a) as well as observations at higher latitudes from the MIPAS and SCIAMACHY instruments789 show that, in agreement with modelling, the mesospheric ozone recovered from the effects of the SPE event by 7–8 November, before the strong EEP forcing is observed.

Bottom Line: However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date.On solar cycle timescales, we find that EEP causes ozone variations of up to 34% at 70-80 km.With such a magnitude, it is reasonable to suspect that EEP could be an important part of solar influence on the atmosphere and climate system.

View Article: PubMed Central - PubMed

Affiliation: Earth Observation, Finnish Meteorological Institute, PO Box 503 (Erik Palménin aukio 1), Helsinki FI-00101, Finland.

ABSTRACT
Energetic electron precipitation (EEP) from the Earth's outer radiation belt continuously affects the chemical composition of the polar mesosphere. EEP can contribute to catalytic ozone loss in the mesosphere through ionization and enhanced production of odd hydrogen. However, the long-term mesospheric ozone variability caused by EEP has not been quantified or confirmed to date. Here we show, using observations from three different satellite instruments, that EEP events strongly affect ozone at 60-80 km, leading to extremely large (up to 90%) short-term ozone depletion. This impact is comparable to that of large, but much less frequent, solar proton events. On solar cycle timescales, we find that EEP causes ozone variations of up to 34% at 70-80 km. With such a magnitude, it is reasonable to suspect that EEP could be an important part of solar influence on the atmosphere and climate system.

No MeSH data available.


Related in: MedlinePlus