scholarly journals The Effect of Forbush Decreases on the Polar-Night HOx Concentration Affecting Stratospheric Ozone

2021 ◽  
Vol 8 ◽  
Author(s):  
Irina Mironova ◽  
Arseniy Karagodin-Doyennel ◽  
Eugene Rozanov

It is well-known that energetic particle precipitations during solar proton events increase ionization rates in the middle atmosphere enhancing the production of hydrogen oxide radicals (HOx) involved in the catalytic ozone destruction cycle. There are many studies where the contribution of energetic particles to the formation of hydrogen oxide radicals and ozone loss has been widely investigated. However, until now, there was no solid evidence that the reduction in galactic cosmic ray fluxes during a magnetic storm, known as Forbush-effect, directly and noticeably affects the polar-night stratospheric chemistry. Here, the impact of the Forbush decrease on the behavior of hydrogen oxide radicals was explored using the chemistry-climate model SOCOLv2. We found that hydrogen oxide radical lost about half of its concentration over the polar boreal night stratosphere owing to a reduction in ionization rates caused by Forbush decreases after solar proton events occurred on 17 and 20 of January 2005. The robust response in ozone was not found. There is not any statistically significant response in (NOx) on Forbush decrease events as well as over summer time in the southern polar region. The results of this study can be used to increase the veracity of ozone loss estimation if stronger Forbush events can have place.

2021 ◽  
Author(s):  
Irina Mironova

<div> <div> <div> <p>It is well-known that energetic particle precipitations during solar proton events increase ionization rates in the middle atmosphere enhancing the production of hydrogen oxide radicals (HOx) involved in the catalytic ozone destruction cycle. There are many studies where the contribution of energetic particles to the formation of hydrogen oxide radicals and ozone loss has been widely investigated. However, until now, there was no solid evidence that the reduction in galactic cosmic ray fluxes during a magnetic storm, known as Forbush-effect, directly and noticeably affects the polar-night stratospheric chemistry.<br>Here, the impact of the Forbush decrease on the behaviour of hydrogen oxide radicals was explored using the chemistry-climate model SOCOL.<br>We found that hydrogen oxide radical lost about half of its concentration over the polar boreal night stratosphere owing to a reduction in ionization rates caused by Forbush decreases after solar proton events occurred on 17 and 20 of January 2005. A robust response in ozone was not found. There is not any statistically significant response in (NOx) on Forbush decrease events as well as over summertime in the southern polar region.<br>The results of this study can be used to increase the veracity of ozone loss estimation if stronger Forbush events can have a place.</p> <p>Reference: Mironova I, Karagodin-Doyennel A and Rozanov E (2021) , The effect of Forbush decreases on the polar-night HOx concentration affecting stratospheric ozone. Front. Earth Sci. 8:618583. doi: 10.3389/feart.2020.618583</p> <p>https://www.frontiersin.org/articles/10.3389/feart.2020.618583/full</p> <p>The study was supported by the Russian Science Foundation grant (RSF project No. 20-67-46016).</p> </div> </div> </div>


2017 ◽  
Author(s):  
Miriam Sinnhuber ◽  
Uwe Berger ◽  
Bernd Funke ◽  
Holger Nieder ◽  
Thomas Reddmann ◽  
...  

Abstract. We analyze the impact of energetic particle precipitation on the stratospheric nitrogen budget, ozone abundances and net radiative heating using results from three global chemistry-climate models considering solar protons and geomagnetic forcing due to auroral or radiation belt electrons. Two of the models cover the atmosphere up to the lower thermosphere, the source region of auroral NO production. Geomagnetic forcing in these models is included by prescribed ionization rates. One model reaches up to about 80 km, and geomagnetic forcing is included by applying an upper boundary condition of auroral NO mixing ratios parameterized as a function of geomagnetic activity. Despite the differences in the implementation of the particle effect, the resulting modeled NOy in the upper mesosphere agrees well between all three models, demonstrating that geomagnetic forcing is represented in a consistent way either by prescribing ionization rates or by prescribing NOy at the model top. Compared with observations of stratospheric and mesospheric NOy from the MIPAS instrument for the years 2002–2010, the model simulations reproduce the spatial pattern and temporal evolution well. However, after strong sudden stratospheric warmings, particle induced NOy is underestimated by both high-top models, and after the solar proton event in October 2003, NOy is overestimated by all three models. Model results indicate that the large solar proton event in October 2003 contributed about 1–2 Gmol (109 mol) NOy per hemisphere to the stratospheric NOy budget, while downwelling of auroral NOx from the upper mesosphere and lower thermosphere contributes up to 4 Gmol NOy. Accumulation over time leads to a constant particle-induced background of about 0.5–1 Gmol per hemisphere during solar minimum, and up to 2 Gmol per hemisphere during solar maximum. Related negative anomalies of ozone are predicted by the models nearly in every polar winter, ranging from 10–50 % during solar maximum to 2–10 % during solar minimum. Ozone loss continues throughout polar summer after strong solar proton events in the Southern hemisphere and after large sudden stratospheric warmings in the Northern hemisphere. During mid-winter, the ozone loss causes a reduction of the infrared radiative cooling, i.e., a positive change of the net radiative heating (effective warming), in agreement with analyses of geomagnetic forcing in stratospheric temperatures which show a warming in the late winter upper stratosphere. In late winter and spring, the sign of the net radiative heating change turns to negative (effective cooling). This spring-time cooling lasts well into summer and continues until the following autumn after large solar proton events in the Southern hemisphere, after sudden stratospheric warmings in the Northern hemisphere.


2009 ◽  
Vol 73 (3) ◽  
pp. 325-327
Author(s):  
V. M. Dvornikov ◽  
M. V. Kravtsova ◽  
A. A. Lukovnikova ◽  
V. E. Sdobnov

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Fusa Miyake ◽  
Kimiaki Masuda ◽  
Toshio Nakamura ◽  
Katsuhiko Kimura ◽  
Masataka Hakozaki ◽  
...  

AbstractTwo radiocarbon excursions (AD 774–775 and AD 993–994) occurred due to an increase of incoming cosmic rays on a short timescale. The most plausible cause of these events is considered to be extreme solar proton events (SPE). It is possible that there are other annual 14C excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the 14C contents in bristlecone pine tree-ring samples during the periods when the rate of 14C increase in the IntCal data is large. We analyzed four periods every other year (2479–2455 BC, 4055–4031 BC, 4465–4441 BC, and 4689–4681 BC), and found no anomalous 14C excursions during these periods. This study confirms that it is important to do continuous measurements to find annual cosmic-ray events at other locations in the tree-ring record.


2014 ◽  
Vol 28 (13) ◽  
pp. 1482001 ◽  
Author(s):  
Rolf Müller ◽  
Jens-Uwe Grooß

Lu's "cosmic-ray-driven electron-induced reaction (CRE) theory" is based on the assumption that the CRE reaction of halogenated molecules (e.g., chlorofluorocarbons (CFCs), HCl, ClONO2) adsorbed or trapped in polar stratospheric clouds in the winter polar stratosphere is the key step in forming photoactive halogen species that are the cause of the springtime ozone hole. This theory has been extended to a warming theory of halogenated molecules for climate change. In this comment, we discuss the chemical and physical foundations of these theories and the conclusions derived from the theories. First, it is unclear whether the loss rates of halogenated molecules induced by dissociative electron attachment (DEA) observed in the laboratory can also be interpreted as atmospheric loss rates, but even if this were the case, the impact of DEA-induced reactions on polar chlorine activation and ozone loss in the stratosphere is limited. Second, we falsify several conclusions that are reported on the basis of the CRE theory: There is no polar ozone loss in darkness, there is no apparent 11-year periodicity in polar total ozone measurements, the age of air in the polar lower stratosphere is much older than 1–2 years, and the reported detection of a pronounced recovery (by about 20–25%) in Antarctic total ozone measurements by the year 2010 is in error. There are also conclusions about the future development of sea ice and global sea level which are fundamentally flawed because Archimedes' principle is neglected. Many elements of the CRE theory are based solely on correlations between certain datasets which are no substitute for providing physical and chemical mechanisms causing a particular behavior noticeable in observations. In summary, the CRE theory cannot be considered as an independent, alternative mechanism for polar stratospheric ozone loss and the conclusions on recent and future surface temperature and global sea level change do not have a physical basis.


2015 ◽  
Vol 33 (3) ◽  
pp. 381-394 ◽  
Author(s):  
P. T. Verronen ◽  
M. E. Andersson ◽  
A. Kero ◽  
C.-F. Enell ◽  
J. M. Wissing ◽  
...  

Abstract. Understanding the altitude distribution of particle precipitation forcing is vital for the assessment of its atmospheric and climate impacts. However, the proportion of electron and proton forcing around the mesopause region during solar proton events is not always clear due to uncertainties in satellite-based flux observations. Here we use electron concentration observations of the European Incoherent Scatter Scientific Association (EISCAT) incoherent scatter radars located at Tromsø (69.58° N, 19.23° E) to investigate the contribution of proton and electron precipitation to the changes taking place during two solar proton events. The EISCAT measurements are compared to the results from the Sodankylä Ion and Neutral Chemistry Model (SIC). The proton ionization rates are calculated by two different methods – a simple energy deposition calculation and the Atmospheric Ionization Model Osnabrück (AIMOS v1.2), the latter providing also the electron ionization rates. Our results show that in general the combination of AIMOS and SIC is able to reproduce the observed electron concentration within ± 50% when both electron and proton forcing is included. Electron contribution is dominant above 90 km, and can contribute significantly also in the upper mesosphere especially during low or moderate proton forcing. In the case of strong proton forcing, the AIMOS electron ionization rates seem to suffer from proton contamination of satellite-based flux data. This leads to overestimation of modelled electron concentrations by up to 90% between 75–90 km and up to 100–150% at 70–75 km. Above 90 km, the model bias varies significantly between the events. Although we cannot completely rule out EISCAT data issues, the difference is most likely a result of the spatio-temporal fine structure of electron precipitation during individual events that cannot be fully captured by sparse in situ flux (point) measurements, nor by the statistical AIMOS model which is based upon these observations.


2008 ◽  
Vol 8 (2) ◽  
pp. 4669-4691 ◽  
Author(s):  
B. Funke ◽  
M. García-Comas ◽  
M. López-Puertas ◽  
N. Glatthor ◽  
G. P. Stiller ◽  
...  

Abstract. In this paper we present evidence of enhanced N2O concentrations in the upper stratosphere/lower mesosphere polar regions after the solar proton events that occurred during October–November 2003. The observations were performed by the MIPAS instrument on the Envisat satellite. Simulations performed using the Canadian Middle Atmospheric Model (CMAM) show that such enhancements are most likely produced by the reaction of N(4S) with NO2, both of which species are largely enhanced just after the solar proton events in the winter polar night.


2014 ◽  
Vol 28 (13) ◽  
pp. 1482002 ◽  
Author(s):  
Q.-B. Lu

In their Comment, Müller and Grooß continuously use problematic "observed data" and misleading arguments to make a case against our CRE mechanism of the ozone hole and CFC-warming mechanism of global climate change. They make the groundless assertion that the CRE theory cannot be considered as an independent process for ozone loss in the polar stratosphere. Their claim that the impact of the CRE mechanism on polar chlorine activation and ozone loss in the stratosphere would be limited does not agree with the observed data over the past decades. They also make many contradictory and fact-distorting arguments that "There is no polar ozone loss in darkness, there is no apparent 11-year periodicity in polar total ozone measurements, the age of air in the polar lower stratosphere is much older than 1–2 years, and the reported detection of a pronounced recovery (by about 20–25%) in Antarctic total ozone measurements by the year 2010 is in error." These assertions ignore and contradict a great deal of robust observed data from both laboratory and field measurements reported in the literature including their own publications. Their new argument for the photodissociation of CFCs on PSCs also contradicts their previous extraordinary efforts including the use of fabricated "ACE-FTS satellite data" to argue for no physical/chemical loss of CFCs in the winter lower polar stratosphere. Finally, they do not provide any scientific evidence to support their criticism for the no physical basis of the CFC-warming theory and its conclusions. In summary, their misleading arguments and false "data" do not change the convincing conclusion reached by robust observations in my recent paper that both the CRE mechanism and the CFC-warming mechanism not only provide new fundamental understandings of the O 3 hole and global climate change but have superior predictive capabilities, compared with the conventional models.


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