Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: the importance of lower ionospheric chemistry

Atmospheric effects of solar proton events (SPEs) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, odd hydrogen and odd nitrogen are produced during SPEs, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the strongest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e., in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase in mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 strongest SPEs which occurred in the years 1989&#8211;2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx and a weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.&#160;

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Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: importance of lower ionospheric chemistry

10.5194/acp-2019-1133 ◽

2020 ◽

Author(s):

Niilo Kalakoski ◽

Pekka T. Verronen ◽

Annika Seppälä ◽

Monika E. Szeląg ◽

Antti Kero ◽

...

Keyword(s):

Climate Model ◽

Middle Atmosphere ◽

Lower Ionosphere ◽

Solar Proton ◽

Atmospheric Effects ◽

Ion Chemistry ◽

Global Models ◽

Superposed Epoch Analysis ◽

D Region ◽

Solar Proton Events

Abstract. Atmospheric effects of solar proton events (SPE) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, SPEs cause production of odd hydrogen and odd nitrogen, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the largest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e. in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase of mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 largest SPEs that occurred in years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx, weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

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Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: the importance of lower ionospheric chemistry

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-8923-2020 ◽

2020 ◽

Vol 20 (14) ◽

pp. 8923-8938 ◽

Cited By ~ 2

Author(s):

Niilo Kalakoski ◽

Pekka T. Verronen ◽

Annika Seppälä ◽

Monika E. Szeląg ◽

Antti Kero ◽

...

Keyword(s):

Climate Model ◽

Middle Atmosphere ◽

Lower Ionosphere ◽

Solar Proton ◽

Atmospheric Effects ◽

Ion Chemistry ◽

Global Models ◽

Superposed Epoch Analysis ◽

D Region ◽

Solar Proton Events

Abstract. Atmospheric effects of solar proton events (SPEs) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, odd hydrogen and odd nitrogen are produced during SPEs, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the strongest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e., in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase in mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 strongest SPEs which occurred in the years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx and a weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

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Ionization increases associated with the small solar proton events of 5 February 1965 and 16 July 1966

Canadian Journal of Physics ◽

10.1139/p69-017 ◽

1969 ◽

Vol 47 (2) ◽

pp. 131-134 ◽

Cited By ~ 2

Author(s):

L. W. Hewitt

Keyword(s):

Lower Ionosphere ◽

Solar Proton ◽

Satellite Observations ◽

Geographic Latitude ◽

Electron Number ◽

Partial Reflection ◽

D Region ◽

Resolute Bay ◽

Solar Proton Events

Observations of partial reflections from the ionosphere at vertical incidence at 2.66 MHz have been made at Resolute Bay, geographic latitude 74.7 °N, since September 1963. By measuring the amplitudes of the ordinary and extraordinary backscattered waves information is obtained about electron number densities in the lower ionosphere. The results presented in this paper show that the partial reflection technique is more sensitive than most other ground-based experiments for the detection of D-region ionization increases associated with small solar proton events. Results obtained by the partial reflection experiment during the events of 5 February 1965 and 16 July 1966 are presented and compared with VLF and satellite observations.

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D-region ion–neutral coupled chemistry (Sodankylä Ion Chemistry, SIC) within the Whole Atmosphere Community Climate Model (WACCM 4) – WACCM-SIC and WACCM-rSIC

Geoscientific Model Development ◽

10.5194/gmd-9-3123-2016 ◽

2016 ◽

Vol 9 (9) ◽

pp. 3123-3136 ◽

Cited By ~ 7

Author(s):

Tamás Kovács ◽

John M. C. Plane ◽

Wuhu Feng ◽

Tibor Nagy ◽

Martyn P. Chipperfield ◽

...

Keyword(s):

Climate Model ◽

Negative Ions ◽

Solar Proton ◽

Proton Event ◽

Ion Chemistry ◽

Neutral Species ◽

Community Climate Model ◽

Ion Molecule Reactions ◽

D Region ◽

Community Climate

Abstract. This study presents a new ion–neutral chemical model coupled into the Whole Atmosphere Community Climate Model (WACCM). The ionospheric D-region (altitudes ∼  50–90 km) chemistry is based on the Sodankylä Ion Chemistry (SIC) model, a one-dimensional model containing 307 ion–neutral and ion recombination, 16 photodissociation and 7 photoionization reactions of neutral species, positive and negative ions, and electrons. The SIC mechanism was reduced using the simulation error minimization connectivity method (SEM-CM) to produce a reaction scheme of 181 ion–molecule reactions of 181 ion–molecule reactions of 27 positive and 18 negative ions. This scheme describes the concentration profiles at altitudes between 20 km and 120 km of a set of major neutral species (HNO3, O3, H2O2, NO, NO2, HO2, OH, N2O5) and ions (O2+, O4+, NO+, NO+(H2O), O2+(H2O), H+(H2O), H+(H2O)2, H+(H2O)3, H+(H2O)4, O3−, NO2−, O−, O2, OH−, O2−(H2O), O2−(H2O)2, O4−, CO3−, CO3−(H2O), CO4−, HCO3−, NO2−, NO3−, NO3−(H2O), NO3−(H2O)2, NO3−(HNO3), NO3−(HNO3)2, Cl−, ClO−), which agree with the full SIC mechanism within a 5 % tolerance. Four 3-D model simulations were then performed, using the impact of the January 2005 solar proton event (SPE) on D-region HOx and NOx chemistry as a test case of four different model versions: the standard WACCM (no negative ions and a very limited set of positive ions); WACCM-SIC (standard WACCM with the full SIC chemistry of positive and negative ions); WACCM-D (standard WACCM with a heuristic reduction of the SIC chemistry, recently used to examine HNO3 formation following an SPE); and WACCM-rSIC (standard WACCM with a reduction of SIC chemistry using the SEM-CM method). The standard WACCM misses the HNO3 enhancement during the SPE, while the full and reduced model versions predict significant NOx, HOx and HNO3 enhancements in the mesosphere during solar proton events. The SEM-CM reduction also identifies the important ion–molecule reactions that affect the partitioning of odd nitrogen (NOx), odd hydrogen (HOx) and O3 in the stratosphere and mesosphere.

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Short- and medium-term atmospheric constituent effects of very large solar proton events

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-765-2008 ◽

2008 ◽

Vol 8 (3) ◽

pp. 765-785 ◽

Cited By ~ 127

Author(s):

C. H. Jackman ◽

D. R. Marsh ◽

F. M. Vitt ◽

R. R. Garcia ◽

E. L. Fleming ◽

...

Keyword(s):

Climate Model ◽

Michelson Interferometer ◽

Geomagnetic Latitude ◽

High Energy ◽

Solar Proton ◽

Atmospheric Effects ◽

Medium Term ◽

Earth’S Atmosphere ◽

Earth's Atmosphere ◽

Solar Proton Events

Abstract. Solar eruptions sometimes produce protons, which impact the Earth's atmosphere. These solar proton events (SPEs) generally last a few days and produce high energy particles that precipitate into the Earth's atmosphere. The protons cause ionization and dissociation processes that ultimately lead to an enhancement of odd-hydrogen and odd-nitrogen in the polar cap regions (>60° geomagnetic latitude). We have used the Whole Atmosphere Community Climate Model (WACCM3) to study the atmospheric impact of SPEs over the period 1963–2005. The very largest SPEs were found to be the most important and caused atmospheric effects that lasted several months after the events. We present the short- and medium-term (days to a few months) atmospheric influence of the four largest SPEs in the past 45 years (August 1972; October 1989; July 2000; and October–November 2003) as computed by WACCM3 and observed by satellite instruments. Polar mesospheric NOx (NO+NO2) increased by over 50 ppbv and mesospheric ozone decreased by over 30% during these very large SPEs. Changes in HNO3, N2O5, ClONO2, HOCl, and ClO were indirectly caused by the very large SPEs in October–November 2003, were simulated by WACCM3, and previously measured by Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). WACCM3 output was also represented by sampling with the MIPAS averaging kernel for a more valid comparison. Although qualitatively similar, there are discrepancies between the model and measurement with WACCM3 predicted HNO3 and ClONO2 enhancements being smaller than measured and N2O5 enhancements being larger than measured. The HOCl enhancements were fairly similar in amounts and temporal variation in WACCM3 and MIPAS. WACCM3 simulated ClO decreases below 50 km, whereas MIPAS mainly observed increases, a very perplexing difference. Upper stratospheric and lower mesospheric NOx increased by over 10 ppbv and was transported during polar night down to the middle stratosphere in several weeks past the SPE. The WACCM3 simulations confirmed the SH HALOE observations of enhanced NOx in September 2000 as a result of the July 2000 SPE and the NH SAGE II observations of enhanced NO2 in March 1990 as a result of the October 1989 SPEs.

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sensitivity of middle atmospheric ozone to solar proton events: comparison between climate model and satellites

10.5194/egusphere-egu21-10818 ◽

2021 ◽

Author(s):

Kenneth Nilsen ◽

Antti Kero ◽

Pekka Verronen ◽

Monika Szelag ◽

Niilo Kalakoski ◽

...

Keyword(s):

Satellite Data ◽

Climate Model ◽

Solar Proton ◽

Proton Flux ◽

Data Sets ◽

Atmospheric Ozone ◽

Ion Chemistry ◽

Solar Proton Events ◽

Good Agreement

Energetic particle precipitation (EPP) impact on the middle atmospheric ozone chemistry plays potentially an important role in the connection between space weather and Earth's climate system. A variant of the Whole Atmosphere Community Climate Model (WACCM-D) implements a detailed set of ionospheric D-region chemistry instead of a simple parameterization used in the earlier WACCM versions, allowing to capture the impact of EPP in more detail, thus improving the model for long-term climate studies. Here, we verify experimentally the ion chemistry of the WACCM-D by analysing the middle atmospheric ozone response to the EPP forcing during well-known solar proton events&#160;(SPEs). We use a multi-satellite approach to derive the middle atmospheric sensitivity for the SPE forcing as a statistical relation between the solar proton flux and the consequent ozone change. An identical sensitivity analysis is carried out for the WACCM-D model results, enabling one-to-one comparison with the results derived from the satellite observations. Our results show a good agreement in the sensitivity between satellites and the WACCM-D for nighttime conditions. For daytime conditions, we find a good agreement for the satellite data sets that include the largest SPEs (max proton flux >10^4 pfu). However, for those satellite data-sets with only minor and moderate SPEs, WACCM-D tends to underestimate the sensitivity in daytime conditions. In summary, the comparisons WACCM-D ion chemistry, combined with the transportation, demonstrates a realistic representation of the SPE sensitivity of ozone, and thus provides a conservative platform for long-term EPP impact studies.

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Short- and medium-term atmospheric effects of very large solar proton events

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-10543-2007 ◽

2007 ◽

Vol 7 (4) ◽

pp. 10543-10588 ◽

Cited By ~ 5

Author(s):

C. H. Jackman ◽

D. R. Marsh ◽

F. M. Vitt ◽

R. R. Garcia ◽

E. L. Fleming ◽

...

Keyword(s):

Climate Model ◽

Stratospheric Ozone ◽

Geomagnetic Latitude ◽

High Energy ◽

Solar Proton ◽

Atmospheric Effects ◽

Medium Term ◽

Earth’S Atmosphere ◽

Earth's Atmosphere ◽

Solar Proton Events

Abstract. Solar eruptions sometimes produce protons, which impact the Earth's atmosphere. These solar proton events (SPEs) generally last a few days and produce high energy particles that precipitate into the Earth's atmosphere. The protons cause ionization and dissociation processes that ultimately lead to an enhancement of odd-hydrogen and odd-nitrogen in the polar cap regions (>60° geomagnetic latitude). We have used the Whole Atmosphere Community Climate Model (WACCM3) to study the atmospheric impact of SPEs over the period 1963–2005. The very largest SPEs were found to be the most important and caused atmospheric effects that lasted several months to years after the events. We present the short- and medium-term (days to a few months) atmospheric influence of the four largest SPEs in the past 45 years (August 1972; October 1989; July 2000; and October–November 2003) as computed by WACCM3 and observed by satellite instruments. The polar effects can be summarized as follows: 1) Mesospheric NOx (NO+NO2) increased by over 50 ppbv and mesospheric ozone decreased by over 30% during these very large SPEs; 2) upper stratospheric and lower mesospheric NOx increased by over 10 ppbv and was transported during polar night down to the middle stratosphere in a few weeks; 3) mid- to upper stratospheric ozone decreased over 20%; and 4) enhancements of HNO3, HOCl, ClO, ClONO2, and N2O5 were indirectly caused by the very large SPEs, although the model results suggest impacts at higher altitudes than indicated by the measurements for the October–November 2003 SPE period.

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