scholarly journals Odd hydrogen response thresholds for indication of solar proton and electron impact in the mesosphere and stratosphere

2020 ◽  
Vol 38 (6) ◽  
pp. 1299-1312
Author(s):  
Tuomas Häkkilä ◽  
Pekka T. Verronen ◽  
Luis Millán ◽  
Monika E. Szeląg ◽  
Niilo Kalakoski ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Signal To Noise Ratio ◽  
Solar Proton ◽  
Polar Regions ◽  
Impact Detection ◽  
Flux Measurements ◽  
Hydrogen Response ◽  
Response Thresholds ◽  
Offline Processing

Abstract. Understanding the atmospheric forcing from energetic particle precipitation (EPP) is important for climate simulations on decadal time scales. However, presently there are large uncertainties in energy flux measurements of electron precipitation. One approach to narrowing these uncertainties is by analyses of EPP direct atmospheric impacts and their relation to measured EPP fluxes. Here we use observations from the microwave limb sounder (MLS) and Whole Atmosphere Community Climate Model (WACCM) simulations, together with EPP fluxes from the Geostationary Operational Environmental Satellite (GOES) and Polar-orbiting Operational Environmental Satellite (POES) to determine the OH and HO2 response thresholds to solar proton events (SPEs) and radiation belt electron (RBE) precipitation. Because of their better signal-to-noise ratio and extended altitude range, we utilize MLS HO2 data from an improved offline processing instead of the standard operational product. We consider a range of altitudes in the middle atmosphere and all magnetic latitudes from pole to pole. We find that the nighttime flux limits for day-to-day EPP impact detection using OH and HO2 are 50–130 protonscm-2s-1sr-1 (E>10 MeV) and 1.0–2.5×104 electronscm-2s-1sr-1 (E = 100–300 keV). Based on the WACCM simulations, nighttime OH and HO2 are good EPP indicators in the polar regions and provide best coverage in altitude and latitude. Due to larger background concentrations, daytime detection requires larger EPP fluxes and is possible in the mesosphere only. SPE detection is easier than RBE detection because a wider range of polar latitudes is affected, i.e., the SPE impact is rather uniform poleward of 60∘, while the RBE impact is focused at 60∘. Altitude-wise, the SPE and RBE detection are possible at ≈ 35–80 and ≈ 65–75 km, respectively. We also find that the MLS OH observations indicate a clear nighttime response to SPE and RBE in the mesosphere, similar to the simulations. However, the MLS OH data are too noisy for response detection in the stratosphere below 50 km, and the HO2 measurements are overall too noisy for confident EPP detection on a day-to-day basis.

scholarly journals Odd hydrogen response thresholds for indication of solar proton and electron impact in the mesosphere and stratosphere

2020 ◽  
Author(s):  
Tuomas Häkkilä ◽  
Pekka T. Verronen ◽  
Luis Millán ◽  
Monika E. Szela̧g ◽  
Niilo Kalakoski ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Solar Proton ◽  
Polar Regions ◽  
Impact Detection ◽  
Climate Simulations ◽  
Flux Measurements ◽  
Hydrogen Response ◽  
Response Thresholds ◽  
Climate Model Simulations

Abstract. Understanding the atmospheric forcing from energetic particle precipitation (EPP) is important for climate simulations on decadal time scales. However, presently there are large uncertainties in energy-flux measurements of electron precipitation. One approach to narrow these uncertainties is by analyses of EPP direct atmospheric impacts and their relation to measured EPP fluxes. Here we use odd hydrogen observations from the Microwave Limb Sounder and Whole Atmosphere Community Climate Model simulations, together with EPP fluxes from the GOES and POES satellites, to determine the response thresholds to solar proton events (SPEs) and radiation belt electron (RBE) precipitation. We consider a range of altitudes in the middle atmosphere, and all magnetic latitudes from pole to pole. We find that the lower flux limits for day-to-day EPP impact detection using OH and HO2 are of the order of 102 protons/cm2/s/sr (E > 10 MeV) and 104 electrons/cm2/s/sr (E = 100–300 keV). Based on the simulations, nighttime OH and HO2 are good EPP indicators in the polar regions, and provide best coverage in altitude and latitude. Due to larger background concentrations, daytime detection requires larger EPP fluxes and is possible in the mesosphere only. SPE detection is easier than RBE detection because a wider range of polar latitudes is affected. We also find that MLS OH observations indicate a clear nighttime response to SPE and RBE in the mesosphere, similar to the simulations, while HO2 data are overall too noisy for confident EPP detection.

scholarly journals Reactive nitrogen (NO<sub><i>y</i></sub>) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

2019 ◽  
Vol 19 (14) ◽  
pp. 9485-9494 ◽  
Author(s):  
Pavle Arsenovic ◽  
Alessandro Damiani ◽  
Eugene Rozanov ◽  
Bernd Funke ◽  
Andrea Stenke ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Stratospheric Ozone ◽  
Energetic Electron ◽  
Polar Vortex ◽  
Solar Proton ◽  
Electron Precipitation ◽  
Reactive Nitrogen ◽  
High Electron

Abstract. Energetic particle precipitation (EPP) affects the chemistry of the polar middle atmosphere by producing reactive nitrogen (NOy) and hydrogen (HOx) species, which then catalytically destroy ozone. Recently, there have been major advances in constraining these particle impacts through a parametrization of NOy based on high-quality observations. Here we investigate the effects of low (auroral) and middle (radiation belt) energy range electrons, separately and in combination, on reactive nitrogen and hydrogen species as well as on ozone during Southern Hemisphere winters from 2002 to 2010 using the SOCOL3-MPIOM chemistry-climate model. Our results show that, in the absence of solar proton events, low-energy electrons produce the majority of NOy in the polar mesosphere and stratosphere. In the polar vortex, NOy subsides and affects ozone at lower altitudes, down to 10 hPa. Comparing a year with high electron precipitation with a quiescent period, we found large ozone depletion in the mesosphere; as the anomaly propagates downward, 15 % less ozone is found in the stratosphere during winter, which is confirmed by satellite observations. Only with both low- and middle-energy electrons does our model reproduce the observed stratospheric ozone anomaly.

scholarly journals Reactive nitrogen (NO<sub><i>y</i></sub>) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

2018 ◽  
Author(s):  
Pavle Arsenovic ◽  
Alessandro Damiani ◽  
Eugene Rozanov ◽  
Bernd Funke ◽  
Andrea Stenke ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Stratospheric Ozone ◽  
Energetic Electron ◽  
Polar Vortex ◽  
Solar Proton ◽  
Electron Precipitation ◽  
Reactive Nitrogen ◽  
High Electron

Abstract. Energetic particle precipitation (EPP) affects the chemistry of the polar middle atmosphere by producing reactive nitrogen (NOy) and hydrogen (HOx) species, which then catalytically destroy ozone. Recently, there have been major advances in constraining these particle impacts through a parametrization based on high quality observations. Here we investigate the effects of low (auroral) and middle (radiation belt) energy range electrons, separately and in combination, on reactive nitrogen and hydrogen species as well as on ozone during Southern Hemisphere winters from 2002 to 2010 using the chemistry-climate model SOCOL3-MPIOM. Our results show that, in absence of solar proton events, low energy electrons produce the majority of NOy in the polar mesosphere and stratosphere. In the polar vortex, NOy subsides and affects ozone at lower altitudes, down to 10 hPa. Comparing a year with high electron precipitation with a quiescent period, we found large ozone depletion in the mesosphere; as the anomaly propagates downward, 15 % less ozone is found in the stratosphere during winter, which is confirmed by satellite observations. Only with both low and middle energy electrons, our model reproduces the observed stratospheric ozone anomaly.

scholarly journals Middle atmospheric ozone, nitrogen dioxide and nitrogen trioxide in 2002–2011: SD-WACCM simulations compared to GOMOS observations

2018 ◽  
Vol 18 (7) ◽  
pp. 5001-5019 ◽  
Author(s):  
Erkki Kyrölä ◽  
Monika E. Andersson ◽  
Pekka T. Verronen ◽  
Marko Laine ◽  
Simo Tukiainen ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Model Simulation ◽  
The Arctic ◽  
Tropical Region ◽  
Satellite Measurement ◽  
Polar Regions ◽  
Wind Fields ◽  
Meteorological Model ◽  
Very High

Abstract. Most of our understanding of the atmosphere is based on observations and their comparison with model simulations. In middle atmosphere studies it is common practice to use an approach, where the model dynamics are at least partly based on temperature and wind fields from an external meteorological model. In this work we test how closely satellite measurements of a few central trace gases agree with this kind of model simulation. We use collocated vertical profiles where each satellite measurement is compared to the closest model data. We compare profiles and distributions of O3, NO2 and NO3 from the Global Ozone Monitoring by Occultation of Stars instrument (GOMOS) on the Envisat satellite with simulations by the Whole Atmosphere Community Climate Model (WACCM). GOMOS measurements are from nighttime. Our comparisons show that in the stratosphere outside the polar regions differences in ozone between WACCM and GOMOS are small, between 0 and 6%. The correlation of 5-day time series show a very high 0.9–0.95. In the tropical region 10° S–10° N below 10 hPa WACCM values are up to 20 % larger than GOMOS. In the Arctic below 6 hPa WACCM ozone values are up to 20 % larger than GOMOS. In the mesosphere between 0.04 and 1 hPa the WACCM is at most 20 % smaller than GOMOS. Above the ozone minimum at 0.01 hPa (or 80 km) large differences are found between WACCM and GOMOS. The correlation can still be high, but at the second ozone peak the correlation falls strongly and the ozone abundance from WACCM is about 60 % smaller than that from GOMOS. The total ozone columns (above 50 hPa) of GOMOS and WACCM agree within ±2 % except in the Arctic where WACCM is 10 % larger than GOMOS. Outside the polar areas and in the validity region of GOMOS NO2 measurements (0.3–37 hPa) WACCM and GOMOS NO2 agree within −5 to +25 % and the correlation is high (0.7–0.95) except in the upper stratosphere at the southern latitudes. In the polar areas, where solar particle precipitation and downward transport from the thermosphere enhance NO2 abundance, large differences up to −90 % are found between WACCM and GOMOS NO2 and the correlation varies between 0.3 and 0.9. For NO3, we find that the WACCM and GOMOS difference is between −20 and 5 % with a very high correlation of 0.7–0.95. We show that NO3 values strongly depend on temperature and the dependency can be fitted by the exponential function of temperature. The ratio of NO3 to O3 from WACCM and GOMOS closely follow the prediction from the equilibrium chemical theory. Abrupt temperature increases from sudden stratospheric warmings (SSWs) are reflected as sudden enhancements of WACCM and GOMOS NO3 values.

scholarly journals Persistence and photochemical decay of springtime total ozone anomalies in the Canadian Middle Atmosphere Model

2007 ◽  
Vol 7 (2) ◽  
pp. 485-493 ◽  
Author(s):  
S. Tegtmeier ◽  
T. G. Shepherd
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Total Ozone ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Correlation Coefficients ◽  
Polar Regions ◽  
Vertical Diffusion ◽  
Ozone Loss ◽  
Atmosphere Model

Abstract. The persistence and decay of springtime total ozone anomalies over the entire extratropics (midlatitudes plus polar regions) is analysed using results from the Canadian Middle Atmosphere Model (CMAM), a comprehensive chemistry-climate model. As in the observations, interannual anomalies established through winter and spring persist with very high correlation coefficients (above 0.8) through summer until early autumn, while decaying in amplitude as a result of photochemical relaxation in the quiescent summertime stratosphere. The persistence and decay of the ozone anomalies in CMAM agrees extremely well with observations, even in the southern hemisphere when the model is run without heterogeneous chemistry (in which case there is no ozone hole and the seasonal cycle of ozone is quite different from observations). However in a version of CMAM with strong vertical diffusion, the northern hemisphere anomalies decay far too rapidly compared to observations. This shows that ozone anomaly persistence and decay does not depend on how the springtime anomalies are created or on their magnitude, but reflects the transport and photochemical decay in the model. The seasonality of the long-term trends over the entire extratropics is found to be explained by the persistence of the interannual anomalies, as in the observations, demonstrating that summertime ozone trends reflect winter/spring trends rather than any change in summertime ozone chemistry. However this mechanism fails in the northern hemisphere midlatitudes because of the relatively large impact, compared to observations, of the CMAM polar anomalies. As in the southern hemisphere, the influence of polar ozone loss in CMAM increases the midlatitude summertime loss, leading to a relatively weak seasonal dependence of ozone loss in the Northern Hemisphere compared to the observations.

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

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.

scholarly journals Middle atmospheric ozone, nitrogen dioxide, and nitrogen trioxide in 2002–2011: SD-WACCM simulations compared to GOMOS observations

2017 ◽  
Author(s):  
Erkki Kyrölä ◽  
Monika E. Andersson ◽  
Pekka T. Verronen ◽  
Marko Laine ◽  
Simo Tukiainen ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Model Simulation ◽  
Tropical Region ◽  
Satellite Measurement ◽  
Polar Regions ◽  
Wind Fields ◽  
Meteorological Model ◽  
Solar Storms ◽  
Very High

Abstract. Most of our understanding of the atmosphere is based on observations and their comparison with model simulations. In the middle atmosphere studies it is common practice to use an approach, where the model dynamics is at least partly based on temperature and wind fields from an external meteorological model. In this work we test how closely satellite measurements of a few central trace gases agree with this kind of model simulation. We use collocated vertical profiles where each satellite measurement is compared to the closest model data. 
We compare profiles and distributions of O3, NO2, and NO3 from the Global Ozone Monitoring by Occultation of Stars instrument (GOMOS) on ENVISAT with simulations by the Whole Atmosphere Community Climate Model (WACCM). GOMOS measurements are from nighttime. Our comparisons show that in the stratosphere outside the polar regions differences in ozone between GOMOS and WACCM are small. The correlation of monthly and 5-day time series show very high correlation. In the tropical region in the lower stratosphere WACCM shows consistently larger values than GOMOS. In the polar areas GOMOS measurements show ozone losses that can be connected to the elevated NO2 concentrations from solar storms and strong down draft events from the thermosphere that take place in the winter polar regions. In the mesosphere above the ozone minimum at 0.01 hPa (or 80 km) large differences are found between WACCM and GOMOS. Correlation can still be high, but at the second ozone peak correlation falls strongly and the ozone abundance from WACCM is about 60 % smaller than from GOMOS. Outside the polar areas and in the validity region 25–0.3 hPa GOMOS and WACCM NO2 agree reasonably well and the correlation is reasonably high except in the upper stratosphere in the southern latitudes. In the polar areas, where solar particle precipitation and downward transport from the thermosphere enhance NOX abundance, large differences are found between GOMOS and WACCM NO2. For NO3, we find WACCM values agreeing largely with GOMOS with very high correlation. We show that NO3 values depend very sensitively on temperature. The ratio of O3 to NO3 follows closely to the prediction from the equilibrium chemical theory. Abrupt temperature increases from Sudden Stratospheric Warmings are reflected as sudden enhancements of GOMOS and WACCM NO3 values. NO3 values can therefore be used as a proxy for major stratospheric warmings.

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

2021 ◽  
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

&lt;p&gt;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 HNO&lt;sub&gt;3&lt;/sub&gt; 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&amp;#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 O&lt;sub&gt;3&lt;/sub&gt;, HO&lt;sub&gt;x&lt;/sub&gt; (OH + HO&lt;sub&gt;2&lt;/sub&gt;), Cl&lt;sub&gt;x&lt;/sub&gt; (Cl + ClO), HNO&lt;sub&gt;3&lt;/sub&gt;, NO&lt;sub&gt;x&lt;/sub&gt; (NO + NO&lt;sub&gt;2&lt;/sub&gt;) and H&lt;sub&gt;2&lt;/sub&gt;O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O&lt;sub&gt;3&lt;/sub&gt; and NO&lt;sub&gt;x&lt;/sub&gt; and a weaker response in HO&lt;sub&gt;x&lt;/sub&gt; and introduces changes in HNO&lt;sub&gt;3&lt;/sub&gt; and Cl&lt;sub&gt;x&lt;/sub&gt;. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.&amp;#160;&lt;/p&gt;

scholarly journals Persistence and photochemical decay of springtime total ozone anomalies in the Canadian Middle Atmosphere Model

2006 ◽  
Vol 6 (2) ◽  
pp. 3403-3417 ◽  
Author(s):  
S. Tegtmeier ◽  
T. G. Shepherd
Keyword(s):  
Seasonal Cycle ◽  
Total Ozone ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Model Performance ◽  
Correlation Coefficients ◽  
Polar Regions ◽  
External Forcing ◽  
Atmosphere Model ◽  
Very High

Abstract. The persistence and decay of springtime total ozone anomalies over the entire extratropics (midlatitudes plus polar regions) is analysed using results from the Canadian Middle Atmosphere Model (CMAM), a comprehensive chemistry-climate model. As in the observations, interannual anomalies established through winter and spring persist with very high correlation coefficients (above 0.8) through summer until early autumn, while decaying in amplitude as a result of photochemical relaxation in the quiescent summertime stratosphere. The persistence and decay of the ozone anomalies in CMAM agrees extremely well with observations, even in the southern hemisphere when the model is run without heterogeneous chemistry (in which case there is no ozone hole and the seasonal cycle of ozone is quite different from observations), and even in the northern hemisphere where this version of CMAM (run with fixed external forcing) strongly underestimates the observed interannual variability. This shows that ozone anomaly persistence and decay does not depend on how the springtime anomalies are created or on their magnitude, but reflects the transport and photochemical decay in the model. It is thus a robust diagnostic of model performance.

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

2020 ◽  
Vol 20 (14) ◽  
pp. 8923-8938 ◽  
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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