Computed contributions to odd nitrogen concentrations in the Earth’s polar middle atmosphere by energetic charged particles

2000 ◽  
Vol 62 (8) ◽  
pp. 669-683 ◽  
Author(s):  
Francis M. Vitt ◽  
Thomas P. Armstrong ◽  
Thomas E. Cravens ◽  
Gisela A.M. Dreschhoff ◽  
Charles H. Jackman ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Charged Particles ◽  
Nitrogen Concentrations ◽  
Odd Nitrogen

scholarly journals Ionization and NO production in the polar mesosphere during high-speed solar wind streams: model validation and comparison with NO enhancements observed by Odin-SMR

2015 ◽  
Vol 33 (5) ◽  
pp. 561-572 ◽  
Author(s):  
S. Kirkwood ◽  
A. Osepian ◽  
E. Belova ◽  
J. Urban ◽  
K. Pérot ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Solar Wind ◽  
Seasonal Variation ◽  
High Speed ◽  
Middle Atmosphere ◽  
Satellite Observations ◽  
Ion Chemistry ◽  
Direct Production ◽  
Order Of Magnitude ◽  
Odd Nitrogen

Abstract. Precipitation of high-energy electrons (EEP) into the polar middle atmosphere is a potential source of significant production of odd nitrogen, which may play a role in stratospheric ozone destruction and in perturbing large-scale atmospheric circulation patterns. High-speed streams of solar wind (HSS) are a major source of energization and precipitation of electrons from the Earth's radiation belts, but it remains to be determined whether these electrons make a significant contribution to the odd-nitrogen budget in the middle atmosphere when compared to production by solar protons or by lower-energy (auroral) electrons at higher altitudes, with subsequent downward transport. Satellite observations of EEP are available, but their accuracy is not well established. Studies of the ionization of the atmosphere in response to EEP, in terms of cosmic-noise absorption (CNA), have indicated an unexplained seasonal variation in HSS-related effects and have suggested possible order-of-magnitude underestimates of the EEP fluxes by the satellite observations in some circumstances. Here we use a model of ionization by EEP coupled with an ion chemistry model to show that published average EEP fluxes, during HSS events, from satellite measurements (Meredith et al., 2011), are fully consistent with the published average CNA response (Kavanagh et al., 2012). The seasonal variation of CNA response can be explained by ion chemistry with no need for any seasonal variation in EEP. Average EEP fluxes are used to estimate production rate profiles of nitric oxide between 60 and 100 km heights over Antarctica for a series of unusually well separated HSS events in austral winter 2010. These are compared to observations of changes in nitric oxide during the events, made by the sub-millimetre microwave radiometer on the Odin spacecraft. The observations show strong increases of nitric oxide amounts between 75 and 90 km heights, at all latitudes poleward of 60° S, about 10 days after the arrival of the HSS. These are of the same order of magnitude but generally larger than would be expected from direct production by HSS-associated EEP, indicating that downward transport likely contributes in addition to direct production.

Satellite-borne measurements of middle-atmosphere composition

1987 ◽  
Vol 323 (1575) ◽  
pp. 545-565 ◽  
Keyword(s):  
Satellite Data ◽  
Middle Atmosphere ◽  
Transport Processes ◽  
Polar Regions ◽  
Polar Night ◽  
Data Set ◽  
The North ◽  
Heterogeneous Processes ◽  
Stratospheric Clouds ◽  
Odd Nitrogen

A number of satellite experiments have been launched in recent years with the goal of providing fundamental data needed for analysis of photochemistry, radiation, dynamics, and transport processes. Collectively, these experiments have accumulated information on the vertical and horizontal distributions of a host of minor constituents in the middle atmosphere. The combined satellite data set includes new global measurements of O 3 , NO 2 , N 2 O , HNO 3 , CH 4 , H 2 O, and aerosols, and more-limited data on CO, N 2 O 5 , CIONO 2 , HNO 4 , COF 2 , and CH 3 CI. These data have provided descriptions of (1) the geographic extent and year-to-year change in the recently discovered Antarctic ozone hole; (2) interannual variability in N 2 O and CH 4 ; (3) the winter high latitude NO 2 ‘cliff’; (4) exchange of NO 2 from the mesosphere to the stratosphere during polar night; (5) a lower limit total odd nitrogen distribution that displays a maximum that exceeds model calculated values; (6) variations in the newly discovered polar stratospheric clouds (PSCS) seen in the north and south polar regions; and (7) details of latitudinal and temporal aerosol variability. The existing satellite data set is deficient in certain key measurements including OH, HO2 , H 2 O 2 , polar night N 2 O 5 , radiatively important aerosol properties, and simultaneous measurements of aerosols and gases involved in heterogeneous processes.

scholarly journals Parameterisation of the chemical effect of sprites in the middle atmosphere

2008 ◽  
Vol 26 (1) ◽  
pp. 13-27 ◽  
Author(s):  
C.-F. Enell ◽  
E. Arnone ◽  
T. Adachi ◽  
O. Chanrion ◽  
P. T. Verronen ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Chemical Effect ◽  
Local Enhancement ◽  
Local Effects ◽  
Transient Luminous Events ◽  
Trace Species ◽  
Global Rate ◽  
Order Of Magnitude ◽  
Red Sprites ◽  
Odd Nitrogen

Abstract. Transient luminous events, such as red sprites, occur in the middle atmosphere in the electric field above thunderstorms. We here address the question whether these processes may be a significant source of odd nitrogen and affect ozone or other important trace species. A well-established coupled ion-neutral chemical model has been extended for this purpose and applied together with estimated rates of ionisation, excitation and dissociation based on spectroscopic ratios from ISUAL on FORMOSAT-2. This approach is used to estimate the NOx and ozone changes for two type cases. The NOx enhancements are at most one order of magnitude in the streamers, which means a production of at most 10 mol per event, or (given a global rate of occurrence of three events per minute) some 150–1500 kg per day. The present study therefore indicates that sprites are insignificant as a global source of NOx. Local effects on ozone are also negligible, but the local enhancement of NOx may be significant, up to 5 times the minimum background at 70 km in extraordinary cases.

scholarly journals Chemistry of sprite discharges through ion-neutral reactions

2008 ◽  
Vol 8 (1) ◽  
pp. 2311-2336 ◽  
Author(s):  
Y. Hiraki ◽  
Y. Kasai ◽  
H. Fukunishi
Keyword(s):  
Electric Field ◽  
Electron Density ◽  
Middle Atmosphere ◽  
Time Behavior ◽  
High Electron ◽  
One Dimensional ◽  
Long Time ◽  
Concentration Changes ◽  
Source Sink ◽  
Odd Nitrogen

Abstract. We estimate the concentration changes, caused by a single streamer in sprites, of ozone and related minor species as odd nitrogen (NOx) and hydrogen (HOx) families in the upper stratosphere and mesosphere. The streamer has an intense electric field and high electron density at its head where a large number of chemically-radical ions and atoms are produced through electron impact on neutral molecules. After propagation of the streamer, the densities of minor species can be perturbed through ion-neutral chemical reactions initiated by the relaxation of these radical products. We evaluate the production rates of ions and atoms using electron kinetics model and assuming the electric field and electron density in the streamer head. We calculate the density variations mainly for NOx, Ox, and HOx species using a one-dimensional model of the neutral and ion composition of the middle atmosphere, including the effect of the sprite streamer. Results at the nighttime condition show that the densities of NO, O3, H, and OH increase suddenly through reactions triggered by firstly produced atomic nitrogen and oxygen, and electrons just after streamer initiation. It is shown that NO and NO2 still remain for 1 h by a certain order of increase with their source-sink balance predominantly around 60 km; for other species, increases in O3, OH, HO2, and H2O2 still remain in the range of 40–70 km. From this affirmative result of long time behavior previously not presented, we emphasize that sprites would have a power to impact on local chemistry at night. We also discuss comparison with previous studies and suggestion for satellite observations.

scholarly journals Modelling the effects of the October 1989 solar proton event on mesospheric odd nitrogen using a detailed ion and neutral chemistry model

2002 ◽  
Vol 20 (12) ◽  
pp. 1967-1976 ◽  
Author(s):  
P. T. Verronen ◽  
E. Turunen ◽  
Th. Ulich ◽  
E. Kyrölä
Keyword(s):  
Chemical Reactions ◽  
Middle Atmosphere ◽  
Solar Proton ◽  
Solar Proton Event ◽  
Atmospheric Composition ◽  
Proton Event ◽  
Chemical Production ◽  
Ion Chemistry ◽  
Composition And Structure ◽  
Odd Nitrogen

Abstract. Solar proton events and electron precipitation affect the concentrations of middle atmospheric constituents. Ionization caused by precipitating particles enhances the production of important minor neutral constituents, such as nitric oxide, through reaction chains in which ionic reactions play an important role. The Sodankylä Ion Chemistry model (SIC) has been modified and extended into a detailed ion and neutral chemistry model of the mesosphere. Our steady-state model (containing 55 ion species, 8 neutral species, and several hundred chemical reactions) is used to investigate the effect of the October 1989 solar proton event on odd nitrogen at altitudes between 50–90 km. The modelling results show that the NO concentration is significantly enhanced due to the proton precipitation, reaching 107 –108 cm-3 throughout the mesosphere on the 20 October when the proton forcing was most severe. A comparison between the chemical production channels of odd nitrogen indicates that ion chemical reactions are an important factor in the total odd nitrogen production during intense ionization. The modelled electron concentration for the 23 October is compared with EISCAT incoherent scatter radar measurements and a reasonable agreement is found.Key words. Atmospheric composition and structure (Middle atmosphere – composition and chemistry); Ionosphere (Particle precipitation)

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