scholarly journals Mesospheric N<sub>2</sub>O enhancements as observed by MIPAS on Envisat during the polar winters in 2002–2004

2008 ◽  
Vol 8 (19) ◽  
pp. 5787-5800 ◽  
Author(s):  
B. Funke ◽  
M. López-Puertas ◽  
M. Garcia-Comas ◽  
G. P. Stiller ◽  
T. von Clarmann ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Major Part ◽  
Polar Vortex ◽  
The Arctic ◽  
Chemical Production ◽  
Additional Source ◽  
Particle Precipitation ◽  
N2o Production ◽  
Energetic Particle Precipitation ◽  
Production Mechanisms

Abstract. N2O abundances ranging from 0.5 to 6 ppbv were observed in the polar upper stratosphere/lower mesosphere by the MIPAS instrument on the Envisat satellite during the Arctic and Antarctic winters in the period July 2002 to March 2004. A detailed study of the observed N2O-CH4 correlations shows that such enhancements cannot be explained by dynamics without invoking an upper atmospheric chemical source of N2O. The N2O enhancements observed at 58 km occurred in the presence of NOx intrusions from the upper atmosphere which were related to energetic particle precipitation. Further, the inter-annual variability of mesospheric N2O correlates well with observed precipitating electron fluxes. The analysis of possible chemical production mechanisms shows that the major part of the observed N2O enhancements is most likely generated under dark conditions by the reaction of NO2 with atomic nitrogen at altitudes around 70–75 km in the presence of energetic particle precipitation (EPP). A possible additional source of N2O in the middle and upper polar atmosphere is the reaction of N2(A3Σu+), generated by precipitating electrons, with O2, which would lead to N2O production peaking at altitudes around 90–100 km. N2O produced by the latter mechanism could then descend to the mesosphere and upper stratosphere during polar winter. The estimated fraction of EPP-generated N2O to the total stratospheric N2O inside the polar vortex above 20 km (30 km) never exceeds 1% (10%) during the 2002–2004 winters. Compared to the global amount of stratospheric N2O, the EPP-generated contribution is negligible.

scholarly journals Mesospheric N<sub>2</sub>O enhancements as observed by MIPAS on Envisat during the polar winters in 2002–2004

2008 ◽  
Vol 8 (3) ◽  
pp. 10561-10596 ◽  
Author(s):  
B. Funke ◽  
M. López-Puertas ◽  
M. García-Comas ◽  
G. P. Stiller ◽  
T. von Clarmann ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Major Part ◽  
The Arctic ◽  
Atomic Nitrogen ◽  
Chemical Production ◽  
Additional Source ◽  
Particle Precipitation ◽  
N2o Production ◽  
Energetic Particle Precipitation ◽  
Production Mechanisms

Abstract. N2O abundances ranging from 0.5 to 6 ppbv were observed in the polar upper stratosphere/lower mesosphere by the MIPAS instrument on the Envisat satellite during the Arctic and Antarctic winters in the period July 2002 to March 2004. A detailed study of the observed N2O–CH4 correlations shows that such enhancements are of chemical rather than dynamical origin. The N2O enhancements observed at 58 km occurred in presence of NOx intrusions from the upper atmosphere which were related to energetic particle precipitation. Further, the inter-annual variability of mesospheric N2O correlates well with observed precipitating electron fluxes. The analysis of possible chemical production mechanisms shows that the major part of the observed N2O enhancements is most likely generated under dark conditions by the reaction of NO2 with atomic nitrogen at altitudes around 70–75 km in the presence of energetic particle precipitation. A possible additional source of N2O in the middle and upper polar atmosphere is the reaction of N2(A3Σu+), generated by precipitating electrons, with O2, which would lead to N2O production peaking at altitudes around 90–100 km. N2O produced by the latter mechanism could then descend to the mesosphere and upper stratosphere during polar winter.

scholarly journals Evidence for energetic particle precipitation and quasi-biennial oscillation modulations of the Antarctic NO<sub>2</sub> springtime stratospheric column from OMI observations

2020 ◽  
Vol 20 (11) ◽  
pp. 6259-6271
Author(s):  
Emily M. Gordon ◽  
Annika Seppälä ◽  
Johanna Tamminen
Keyword(s):  
Energetic Particle ◽  
Activity Index ◽  
Polar Vortex ◽  
Late Winter ◽  
Ozone Monitoring Instrument ◽  
Particle Precipitation ◽  
Quasi Biennial Oscillation ◽  
Energetic Particle Precipitation ◽  
The Antarctic ◽  
Biennial Oscillation

Abstract. Observations from the Ozone Monitoring Instrument (OMI) on the Aura satellite are used to study the effect of energetic particle precipitation (EPP, as proxied by the geomagnetic activity index, Ap) on the Antarctic stratospheric NO2 column in late winter–spring (August–December) during the period from 2005 to 2017. We show that the polar (60–90∘ S) stratospheric NO2 column is significantly correlated with EPP throughout the Antarctic spring, until the breakdown of the polar vortex in November. The strongest correlation takes place during years with the easterly phase of the quasi-biennial oscillation (QBO). The QBO modulation may be a combination of different effects: the QBO is known to influence the amount of the primary NOx source (N2O) via transport from the Equator to the polar region; and the QBO phase also affects polar temperatures, which may provide a link to the amount of denitrification occurring in the polar vortex. We find some support for the latter in an analysis of temperature and HNO3 observations from the Microwave Limb Sounder (MLS, on Aura). Our results suggest that once the background effect of the QBO is accounted for, the NOx produced by EPP significantly contributes to the stratospheric NO2 column at the time and altitudes when the ozone hole is present in the Antarctic stratosphere. Based on our findings, and the known role of NOx as a catalyst for ozone loss, we propose that as chlorine activation continues to decrease in the Antarctic stratosphere, the total EPP-NOx needs be accounted for in predictions of Antarctic ozone recovery.

scholarly journals Atmospheric effects of energetic particle precipitation in the Arctic winter 1978-1979 revisited

2012 ◽  
Vol 117 (D5) ◽  
pp. n/a-n/a ◽  
Author(s):  
L. A. Holt ◽  
C. E. Randall ◽  
V. L. Harvey ◽  
E. E. Remsberg ◽  
G. P. Stiller ◽  
...  
Keyword(s):  
Energetic Particle ◽  
The Arctic ◽  
Atmospheric Effects ◽  
Particle Precipitation ◽  
Energetic Particle Precipitation

scholarly journals Nitric acid in the stratosphere based on Odin observations from 2001 to 2007 – Part 2: High-altitude polar enhancements

2008 ◽  
Vol 8 (3) ◽  
pp. 9591-9605 ◽  
Author(s):  
Y. J. Orsolini ◽  
J. Urban ◽  
D. P. Murtagh
Keyword(s):  
Nitric Acid ◽  
Energetic Particle ◽  
Polar Vortex ◽  
Solar Proton ◽  
Auroral Zone ◽  
Lower Atmosphere ◽  
Particle Precipitation ◽  
Annual Cycles ◽  
Energetic Particle Precipitation ◽  
Solar Proton Events

Abstract. The wintertime abundance of nitric acid (HNO3) in the polar upper stratosphere displays a strong inter-annual variability, and is known to be strongly influenced by energetic particle precipitation, primarily during solar proton events, but also by precipitating electrons in the auroral zone. While wintertime HNO3 enhancements in the polar upper stratosphere had been occasionally observed before, from the ground or from satellite, we present here measurements by the Sub-Millimeter Radiometer instrument aboard the Odin satellite through 6 full annual cycles (2001 to 2007). Major solar proton events, e.g. during November 2001 or the Halloween solar storms of autumn 2003, lead to a two-stage HNO3 enhancement, likely involving different chemical reactions: a fast (about 1 week) in-situ enhancement from the mid to the upper stratosphere is followed by a slower, longer-lasting one, whereby anomalies originating in the upper stratosphere can descend within the polar vortex into the lower stratosphere. We highlight the fact that the actual chemical coupling between the upper and lower atmosphere involves a complex interplay of chemistry, dynamics and energetic particle precipitation.

scholarly journals Impact of energetic particle precipitation on stratospheric polar constituents: an assessment using MIPAS data monitoring and assimilation

2009 ◽  
Vol 9 (5) ◽  
pp. 22459-22504
Author(s):  
A. Robichaud ◽  
R. Ménard ◽  
S. Chabrillat ◽  
J. de Grandpré ◽  
Y. J. Rochon ◽  
...  
Keyword(s):  
Gas Phase ◽  
Energetic Particle ◽  
Solar Proton ◽  
Significant Loss ◽  
Proton Event ◽  
Particle Precipitation ◽  
Gas Phase Chemistry ◽  
Energetic Particle Precipitation ◽  
Phase Chemistry ◽  
Assimilation System

Abstract. In 2003, strong geomagnetic events occurred which produced massive amounts of energetic particles penetrating the top of the atmospheric polar region, significantly perturbing its chemical state down to the middle stratosphere. These events and their effects are generally left unaccounted for in current models of stratospheric chemistry and large differences between observations and models are then noted. In this study, we use a coupled 3-D stratospheric dynamical-chemical model and assimilation system to ingest MIPAS temperature and chemical observations. The goal is to gain further understanding and to evaluate the impacts of EPP (energetic particle precipitation) on stratospheric polar chemistry. Moreover, we investigate the feasibility of assimilating valid "outlier" observations associated with such events. We focus our analysis on OmF (Observation minus Forecast) residuals as they filter out phenomena well reproduced by the model (such as gas phase chemistry, transport, diurnal and seasonal cycles) thus revealing a clear trace of the EPP. Inspection of OmF statistics in both the passive (without chemical assimilation) and active (with chemical assimilation) cases altogether provides a powerful diagnostic tool to assess the model and assimilation system. We also show that passive OmF can permit a satisfactory evaluation of the ozone partial column loss due to EPP effects. Results suggest a small but significant loss of 5–6 DU (Dobson Units) during an EPP-IE (EPP indirect effects) event in the Antarctic winter of 2003, and about only 1 DU for the SPE (solar proton event) of October/November 2003. Despite large differences between the model and MIPAS chemical observations (NO2, HNO3, CH4 and O3), we demonstrate that a careful assimilation of these constituents with only gas phase chemistry included in the model (i.e. no provision for EPP impacts) and with relaxed quality control nearly eliminated the short-term bias and significantly reduced the standard deviation error below 1 hPa.

scholarly journals Energetic particle precipitation in the Brazilian geomagnetic anomaly during the “Bastille Day storm” of July 2000

2006 ◽  
Vol 58 (5) ◽  
pp. 607-616 ◽  
Author(s):  
Masanori Nishino ◽  
Kazuo Makita ◽  
Kiyofumi Yumoto ◽  
Yoshizumi Miyoshi ◽  
Nelson J. Schuch ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Particle Precipitation ◽  
Energetic Particle Precipitation ◽  
Geomagnetic Anomaly
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