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Advances in Space Research 38 (2006) 1881–1886

Ozone depletion in the middle atmosphere duringsolar proton events in October 2003

Kh. Fadel a, E.V. Vashenyuk b, A.S. Kirillov b,*

a Swedish Institute of Space Physics, Umea University, Kiruna, Swedenb Polar Geophysical Institute, Apatity, Murmansk region, Russia

Received 23 December 2004; received in revised form 18 April 2006; accepted 19 April 2006

Abstract

A one-dimensional time-dependent model has been used to calculate the production and loss of minor components of the middleatmosphere during solar proton precipitations in October 2003. We used the solar proton fluxes measured on the GOES-11 spacecraftto estimate the rates of ion–electron pair, odd-nitrogen and odd-hydrogen production. Our calculations show that the production of odd-hydrogen causes the ozone depletion by the factor 2 and more at the altitudes higher than 55 km. This depletion is in an agreement withmeasurements of O3 altitude profiles made on POAM-3 satellite.� 2006 COSPAR. Published by Elsevier Ltd. All rights reserved.

Keywords: Solar proton event; Middle atmosphere; Ozone depletion; Odd-nitrogen; Odd-hydrogen

1. Introduction

Solar protons precipitating in the middle atmosphereproduce large amounts of odd-nitrogen, odd-hydrogenand electronically excited atoms and molecules (Ruschet al., 1981; Solomon et al., 1981, 1983a; Jackman et al.,2000; Krivolutsky et al., 2001; Kirillov, 2004a). The odd-ni-trogen NOx and odd-hydrogen HOx can cause ozonedepletion in the mesosphere and stratosphere through thecatalytic cycles (including NO + NO2 and H + OH + HO2)(Brasseur and Solomon, 1984):

NOx + O3!NOxþ1 + O2, ð1aÞ

NOxþ1 + O!NOx + O2, x = 1, ð1bÞ

and

HOx + O3!HOxþ1 + O2, ð2aÞ

HOxþ1 + O!HOx + O2, x = 0, 1. ð2bÞ

0273-1177/$30 � 2006 COSPAR. Published by Elsevier Ltd. All rights reserv

doi:10.1016/j.asr.2006.04.015

* Corresponding author. Tel.: +7 81555 79760.E-mail addresses: sunactivity@yahoo.se (Kh. Fadel), kirillov@pgi.

kolasc.net.ru (A.S. Kirillov).

Moreover, solar protons and secondary electrons causethe effective electronic excitation of main atmospheric com-ponents N2 and O2 in inelastic collisions. It was proposedin (Toumi, 1993; Zipf and Prasad, 1998) that electronicallyexcited molecular oxygen could cause the sufficient produc-tion of odd-nitrogen and odd-hydrogen through reactionsin the middle atmosphere. Also it was concluded in(Kirillov, 2004a) that there is an effective production ofsinglet molecular oxygen (excited in metastable a1Dg orb1Rþg states principally in vibrational level v = 0) and highlyvibrationally excited O2 (in ground X 3R�g state, v > 20)in the middle atmosphere during solar proton events(SPEs).

Here we do not consider, however, any role of electronicand vibration kinetics in chemical balance of the middleatmosphere. This is the complicated independent taskwhich is beyond the given study. So here we will limit our-selves by the ‘‘traditional’’ point of view in the calculationof the odd-nitrogen and odd-hydrogen influence on theozone balance according to processes (1a,b) and (2a,b).The main goal of the paper is to study ozone concentrationdepletions observed in the middle atmosphere during SPEseries in October 2003.

ed.

1882 Kh. Fadel et al. / Advances in Space Research 38 (2006) 1881–1886

2. The model

The model considers a production of a set of minorcomponents in the middle atmosphere by the solar lightabsorption and by energetic proton and secondary electronimpacts. The set includes atomic oxygen O(3P, 1D), ozoneO3, atomic nitrogen N(4S, 2D), odd-nitrogen NOx (nitricoxide, nitrogen dioxide and trioxide), dinitrogen pentoxideN2O5, nitrous oxide N2O, odd-hydrogen HOx (atomichydrogen, hydroxyl and hydroperoxy radicals), even-hy-drogen H2Ox (molecular hydrogen, water vapor andhydrogen peroxide), HNOx (nitrous, nitric and peroxyni-tric acids), COx (carbon monoxide and dioxide), CHx

(methyl and methane), CHxOy (formyl radical, formalde-hyde, methoxy and methylperoxy radicals and methylhydroperoxide), chlorine and bromide compounds: X2,X, HX, HOX, XO and XONO2 (here X = Cl or Br),unsymmetric ClOO and symmetric OClO chlorine diox-ides, chlorine oxides Cl2Ox (x = 1–3), BrCl. One hundredand thirty seven chemical reactions between the compo-nents are included in the model (Atkinson et al., 2005;Sander et al., 2003).

Since the reaction of nitrous oxide with electronicallyexcited atomic oxygen

N2O + O (1D)!NO + NO ð3Þ

is the main production channel of odd-nitrogen in thestratosphere during quiet period (Jackman et al., 1980)we input N2O concentrations according to (Olsen et al.,2001). The source of odd-hydrogen is the direct photolysisof H2O and by the reactions (Solomon et al., 1983b; Crut-zen, 1997)

H2O + O (1D)!OH + OH, ð4Þ

H2 + O (1D)!H + OH. ð5Þ

The concentrations of even hydrogen H2O and H2 weretaken equal to 6 ppmv and 0.5 ppmv, respectively, (Robleand Dickinson, 1989), decreasing at altitudes higher than70 km and lower than 40 km for H2O (Gunson et al.,1990; Zhou et al., 1997). So concentration profiles ofN2O, H2O and H2 are taken as invariable in time in ourcalculations.

Also we consider concentration profiles for carbon diox-ide CO2 and methane CH4 as invariable. Data for CO2

were taken according to (Zaragoza et al., 2000) and forCH4 according to (Gunson et al., 1990; Zhou et al.,1997). Seasonal variation of long-lived trace gases (Sum-mers et al., 1997) are neglected in our consideration.

We input initial concentration profiles for chlorine com-pounds HCl, HOCl, ClO and ClONO2 according to(Michelsen et al., 1996; Zander et al., 1996). Initial concen-tration profiles for bromine compounds Br2, Br, HBr,HOBr, BrO, BrONO2 and BrCl were taken according toBrO profiles measured in (Harder et al., 1998) and normal-ised to be in agreement with model data of Lary (1996).

Different spectral intervals of the solar light are impor-tant in the dissociative processes of O2 and minor compo-nents, so the solar spectral irradiance in visible andultraviolet regions used in the model calculations was takenaccording to (Mount and Rottman, 1981; Nicolet, 1989).Absorption cross sections for major gas O2 and minorcomponents were taken mainly according to (Atkinsonet al., 2005; Finlayson-Pitts and Pitts, 2000; Sander et al.,2003). All spectrum diapason 120–900 nm is divided inthe intervals with the width of 1 nm. The decrease of theintensity of solar light in the every interval was calculatedaccording to exponential Lambert–Beer law where theoptical depth at the altitude h includes the contributionof all atmospheric components having non-zero cross sec-tions of solar light absorption.

To calculate the rates of ion–electron pair production byprecipitated particles we use the following formula for ratesof solar proton energy dissipated in cubic centimeter persecond at the altitude h (Dorman, 1975, chapter 6):

wðhÞ ¼ qðhÞAZ Emax

Emin

Z p2

0

f ðEÞ Emþ1 � Aðmþ 1Þ Xcos h

� � mmþ1

� 2p sin hdE dh: ð6Þ

Here q is the density of the atmosphere, f(E) is the energeticspectrum of solar protons, X is the respective depth ing/cm2, Emin = 1 MeV, Emax = 400 MeV and parameters A

and m are equal to 242 and 0.75, respectively. The rate ofion–electron pair production is related with the valuew(h) by the relation

qðhÞ ¼ wðhÞQ

; ð7Þ

where Q is equal to 35 eV. Here we suggest the isotropicdistribution of solar protons on the pitch angle h in allour calculations.

The continuity non-stationary equations

oni

ot¼ o

ohD

oni

ohþ 1

ToTohþ 1

Hi

� �ni

� �� �þ P i � Lini ð8Þ

are solved for minor components of the middle atmo-sphere. Here ni and Hi is the concentration and the scaleheight of the ith component, D is the diffusion coefficient,T is the temperature, Pi and Li are the production and lossrates of the ith component. The production and loss ratesinclude the contributions from dissociative processes relat-ed with solar light inelastic scattering, chemical reactions,production of minor components in collisions of protonsand secondary electrons with main atmospheric compo-nents. Diffusion coefficient adopted in our study was takenaccording to (Crutzen et al., 1978). Upper and lower bor-ders in our calculation are at 90 km and 20 km, respective-ly. Border conditions are given fluxes at 90 km andphotochemical equilibrium at 20 km. The time integrationof Eq. (8) were carried out explicitly, in which case the spa-tial derivative terms are only evaluated at known time (pre-ceding step in time) (Rood, 1987). Time and altitude steps

Table 1Characteristics of solar flares

Date X-ray 1-8 A max Flare importance Heliocoordinates

28. 10. 2003 11.10 4B/X17.2 S16E0829. 10. 2003 20.49 2B/X10.0 S15W02

Fig. 1. Intensity profiles of energetic solar protons on October 28–30,2003: 1 – E > 10 MeV, 2 – E > 30 MeV and 3 – E > 100 MeV; a – 6.00 UTof 28.10, b – 18.00 UT of 28.10, c – 6.00 UT of 29.10, d – 18.00 UT of29.10 and e – 6.00 UT of 30.10.

Kh. Fadel et al. / Advances in Space Research 38 (2006) 1881–1886 1883

for the integration in our calculation were taken equal to0.1 s and 1 km, respectively.

Since electronically excited atomic oxygen participatingin chemical reactions (3)–(5) is responsible for the produc-tion of odd-nitrogen and odd-hydrogen in the quiet atmo-sphere. The atoms are produced mainly inphotodissociation processes related with molecular oxygenO2, ozone O3, nitrous oxide N2O, water vapor H2O andcarbon dioxide CO2.

The production of electronically excited atomic oxygenO(1D) in the process

O2 + hm!O + O (1D)

is believed to be possible only in the Schumann-Rungecontinuum and by Lyman-a line. Cross sections for thespectrum interval 130–175 nm have been taken accordingto (Watanabe et al., 1953; Goldstein and Mastrup, 1966).A quantum yield of unity is for the interval 139–175 nmand with oscillating structure for the interval 130–138 nm(Nee and Lee, 1997). Although the results of (Lacour-siere et al., 1999) have revealed a strongly wavelength-de-pendent window in the O(1D) yield, we have acceptedthe value of 0.44 from sufficiently earlier laboratorystudy (Lee et al., 1977). The solar light absorption inthe Herzberg continuum and in the Schumann-Rungebands for O2 is supposed to cause a production of twooxygen atoms in the ground state 3P (Yoshino et al.,1988, 1992).

The solar light absorption of O3 in the Hartley, Hugginsand Chappuis bands causes the dissociation of ozone mol-ecule. Only the scattering in Hartley and Huggins bands isbelieved to have the production of O(1D) (Matsumi andKawasaki, 2003) in the process

O3 + hm!O2 + O (1D).

We suggest the quantum yield of O(1D) about 0.90 forspin-allowed channel with the production of O2 (a1Dg) forthe 185–305 nm interval (Atkinson et al., 2005) anddecreasing yield for higher k (305–330 nm) according to(Armerding et al., 1995; Talukdar et al., 1998). The solarlight scattering in Huggins (330–350 nm) and Chappuisbands (440–750 nm) causes only the production of twooxygen atoms in ground state.

Absorption spectrum of nitrous oxide N2O was takenaccording to (Finlayson-Pitts and Pitts, 2000) for the spec-tral interval 173–240 nm. The molecule absorbs and disso-ciates with unit quantum yield to N2 and electronicallyexcited atomic oxygen

N2O + hm!N2 + O (1D)

(Sander et al., 2003; Atkinson et al., 2005).Absorption spectrum of water vapor H2O was taken

according to (Brasseur and Solomon, 1984) for the spectralinterval 120–200 nm. The quantum yield of 0.11 for theprocess

H2O + hm!H2 + O (1D)

is suggested for spectral interval 120–145 nm (Stief et al.,1975). The cross section for solar Lyman-a line (121.6 nm)is equal to 2 · 10�17 cm2 (Sonnemann et al., 1977).

Absorption spectrum of carbon dioxide CO2 was takenaccording to (Thompson et al., 1963) for the spectral inter-val 120–200 nm. The quantum yield of 1.0 for the process

CO2 + hm!CO + O (1D)

is suggested for spectral interval 120–167 nm (Lin and Bau-er, 1969).

3. Experimental data on solar protons

Ionization effects in middle atmosphere in late October,2003 were caused by the SPEs of 28 and 29 October. Char-acteristics of the parent solar flares are presented in Table1. Fig. 1 shows intensity profiles of solar protons with ener-gies >10 MeV, >30 MeV and >100 MeV as measured atGOES-11 spacecraft. Two maxima on the intensity curvescorrespond to the two SPEs: on 28 and 29 October. Byarrows at the time axis are shown the times of the relevantflares (Table 1). The date, the time of X-ray maximum(probable moment of particle acceleration), flare impor-tance and heliocoordinates are shown in respective col-umns of Table 1.

The differential energy spectra of solar protons werederived using the GOES-11 data in the integral energy

Fig. 2. Derived spectra of solar protons for five times (a–e) as in Fig. 1.

Fig. 4. Profiles of O3 concentrations measured on POAM-3 satellite: 1 –22.00 UT of 27.10, 2 – 22.00 UT of 28.10 and 3 – 22.00 UT of 30.10.

1884 Kh. Fadel et al. / Advances in Space Research 38 (2006) 1881–1886

channels: >1 MeV, >5 MeV, >10 MeV, >30 MeV,>50 MeV and >100 MeV for every hour in the period from11.00 UT of 28.10 to the end of day of 30.10. The spectraderived in five moments of time, corresponding to markedby characters ‘a’, ‘b’, ‘c’, ‘d’ and ‘e’ in Fig. 1 are shown inFig. 2. The relevant position of the spectra in vertical axiscorrespond to the intensity variations of solar protons dur-ing the considered period (Fig. 1).

Fig. 3 shows the ionization profiles calculated usingspectra ‘a’–‘e’ and formulas (6) and (7). The profile ‘a’ cor-responds to ionization state before the start of SPE of28.10. Profiles ‘b’ and ‘c’ correspond to the intensity max-imum of the SPE of 28.10. The profile ‘d’ is calculated forthe period before the start of SPE of 29.10, and the profile‘e’ is for its maximum. A little difference between the spec-tra ‘d’ and ‘e’ was because of sufficiently high intensity ofsolar protons produced in SPE of 28.10 retained up to

Fig. 3. Calculated ion production rate due to solar protons for five times(a–e) as in Fig. 1.

the start of SPE of 29.10. The profiles are in good agree-ment with similar calculations in (Jackman et al., 2005)showing the ion pair production more than 104 cm�3 s�1

at the altitude interval 45–80 km of 28–29.10.

4. Results of calculations and comparisons with experimental

data

Altitude profiles of O3 concentration measured onPOAM-3 satellite are shown in Fig. 4. The altitude profilesat the point (70�N and 110�W) are presented for 22.00 UTof 27.10 (quiet) and 22.00 UT of 28.10 and 30.10 (after SPEseries). As it is seen from Fig. 1 during the period of 28–30October a series of powerful SPEs has occurred. The ozonedepletion at the altitudes higher than about 50 km after theseries of very strong SPEs can be seen in the figure. A littledecrease at smaller altitudes (30–40 km) can be to consideras negligible.

The results of our calculations of ozone concentrationsfor a quiet period for 12.00 LT of 27.10 and for 12.00LT of 29.10 and 30.10 are shown in Fig. 5. The significantozone depletions (factor 2 and more) is obtained for alti-tude interval higher than 55 km. We suggested in the calcu-lations that in the middle atmosphere the odd-nitrogen andodd-hydrogen produced per ion–electron pair has theratios of 1.3 and 2.0, respectively (Heaps, 1978; Ruschet al., 1981; Solomon et al., 1981). The averaged GOES-11 solar proton data for 00.00–12.00 UT on 26 Octoberare taken as background proton intensities for quietperiods.

We see from Fig. 3 that the processes of the ionizationand odd-nitrogen and odd-hydrogen production are effec-tive only at the altitudes higher than 40 km for isotropicdistribution on pitch angles for solar protons. The calcula-tions of altitude profiles of atmospheric components haveshown the obtained decrease in ozone concentrations iscaused by OH production and the chemical process

Fig. 5. Calculated profiles of O3 concentrations: 1 – 12.00 LT of 27.10,2 – 12.00 LT of 29.10 and 3 – 12.00 LT of 30.10.

Kh. Fadel et al. / Advances in Space Research 38 (2006) 1881–1886 1885

(2a,b) having high rate coefficients of the interaction. Thisdecrease of ozone concentrations in northern hemisphere isin good agreement with ozone estimations made accordingto limb scatter measurements with the SCIAMACHYinstrument on the Envisat spacecraft in (Rohen et al.,2005). Similar ozone depletion on October 28, 2003 wasobserved on the Odin satellite over the southern polarcap in (Degenstein et al., 2005). The production of odd-ni-trogen and the chemical process (1a,b) during SPEs doesnot cause the ozone decrease for the considered period(2–3 days). Stratospheric effects of the particle precipita-tions in the reduction of O3 are strongly pronounced onlyfew months later (Randall et al., 2005).

5. Conclusions

A one-dimensional time-dependent model of the mid-dle atmosphere is applied to estimate the changes ofminor components during SPEs of 28–30 October of2003. Following Heaps (1978), Rusch et al. (1981) andSolomon et al. (1981) we use the ratios of 1.3 and 2.0of the production of the odd-nitrogen and odd-hydrogenper ion–electron pair. Our calculations have shown thatthe main factor causing the ozone content decrease inthe middle atmosphere during solar proton precipitationsis the odd-hydrogen species production through the mul-tiple hydrogen and subsequent recombination in theionization products. Here we have not considered theinfluence of electronically excited atomic and molecularcomponents on the production of odd-hydrogen andodd-nitrogen and ozone balance in the middle atmo-sphere during SPE discussed in (Toumi, 1993; Zipf andPrasad, 1998; Kirillov, 2004a) but leave the issue forfuture investigations. The conclusion of (Kirillov, 2004a)about effective production of singlet oxygen in the middleatmosphere during SPE is based on good agreement ofcalculated quenching rate coefficients of electronically

excited N2 and O2 with recent laboratory data obtainedin (Kirillov, 2003, 2004b). Since the ozone concentrationdecreases depend on the amounts of these producedatmospheric components as well as on the rate coeffi-cients of the chemical reactions, so the influence of elec-tronically excited atmospheric components on the ozonebalance could take place in the middle atmosphere duringlarge disturbances.

Acknowledgements

The work of E.V.V. is supported by the Grants 05-02-17143 and 03-02-96026 of Russian Foundation for BasicResearch (RFBR). The work of A.S.K. is supported bythe Grants 05-05-64271, 06-05-65044 and 03-02-96026 ofRFBR. The work of Kh. Fadel is supported by the Grantsof Swedish Institute.

References

Armerding, W., Comes, F.J., Schulke, B. O(1D) quantum yields of ozonephotolysis in the UV from 300 to its threshold and at 355 nm. J. Phys.Chem. 99, 3137–3143, 1995.

Atkinson, R., Baulch, D.L., Cox, R.A., Crowley, J.N., Hampson, R.F.,Jr., Hynes, R.G., Jenkin, M.E., Kerr, J.A., Rossi, M.J., Troe, J.Summary of evaluated kinetic and photochemical data for atmospher-ic chemistry. In: IUPAC subcommittee on gas kinetic data evaluationfor atmospheric chemistry, 2005.

Brasseur, G., Solomon, S. Aeronomy of the Middle Atmosphere. D.Reidel Publ. Cy., Dordrecht, Holland, 1984.

Crutzen, P. Mesospheric mysteries. Science 277, 1951–1952, 1997.Crutzen, P., Isaksen, I.S.A., McAfee, J.R. The impact of the chlorocarbon

industry on the ozone layer. J. Geophys. Res. 83, 345–363, 1978.Degenstein, D.A., Lloyd, N.D., Bourassa, A.E., Gattinger, R.L., Llewel-

lyn, E.J. Observations of mesospheric ozone depletion during theOctober 28, 2003 solar proton event by OSIRIS. Geophys. Res. Lett.32, L03S11, doi:10.1029/2004GL021521, 2005.

Dorman, L.I. Experimental and Theoretical Background of Astrophysicsof Cosmic Rays. Nauka, Moscow (in Russian), 1975.

Finlayson-Pitts, B.J., Pitts Jr., J.N. Chemistry of the Upper and LowerAtmosphere. Academic Press, New York, 2000.

Goldstein, R., Mastrup, F.N. Absorption coefficients of the O2 Schu-mann-Runge continuum from 1270 A to 1745 A using a new contin-uum source. J. Opt. Soc. Am. 56, 765–769, 1966.

Gunson, M.R., Farmer, C.B., Norton, R.H., Zander, R., Rinsland, C.P.,Shaw, J.H., Gao, B.-C. Measurements of CH4, N2O, CO, H2O, and O3

in the middle atmosphere by the atmospheric trace molecule spectros-copy experiment on spacelab 3. J. Geophys. Res. 95, 13867–13882,1990.

Harder, H., Camy-Peyret, C., Ferlemann, F., Fitzenberger, R., Hawat, T.,Osterkamp, H., Schneider, M., Perner, D., Platt, U., Vradelis, P.,Pfeilsticker, K. Stratospheric BrO profiles measured at differentlatitudes and seasons: atmospheric observations. Geophys. Res. Lett.25, 3843–3846, 1998.

Heaps, M.G. The production rates of odd-hydrogen and odd-nitrogenspecies for ionizing events in the mesosphere and upper stratosphere.Eos Trans. AGU 59, 341, 1978.

Jackman, C.H., DeLand, M.T., Labow, G.J., Fleming, E.L., Weisenstein,D.K., Ko, M.K.W., Sinnhuber, M., Russell, J.M. Neutral atmosphericinfluences of the solar proton events in October–November 2003. J.Geophys. Res. 110, A09S27, doi:10.1029/2004JA010888, 2005.

Jackman, C.H., Fleming, E.L., Vitt, F.M. Influence of extremely largesolar proton events in a changing stratosphere. J. Geophys. Res. 105,11659–11670, 2000.

1886 Kh. Fadel et al. / Advances in Space Research 38 (2006) 1881–1886

Jackman, C.H., Frederick, J.E., Stolarski, R.S. Production of oddnitrogen in the stratosphere and mesosphere: An intercomparison ofsource strengths. J. Geophys. Res. 85, 7495–7505, 1980.

Kirillov, A.S., Estimation of temperature dependence of electronicquenching rate coefficients using quantum-chemical approximationsfor molecular oxygen and molecular nitrogen. In: Proceedings of the30th Annual European Meeting on Atmospheric Studies by OpticalMethods, Longyearbyen, Norway, 2003, pp. 38–42.

Kirillov, A.S. Production of singlet oxygen in Earth atmosphere duringsolar proton precipitations. Ekologicheskaya chimiya 13, 69–78 (inRussian), 2004a.

Kirillov, A.S. Calculation of rate coefficients of electron energy transferprocesses for molecular nitrogen and molecular oxygen. Adv. SpaceRes. 33, 998–1004, 2004b.

Krivolutsky, A.A., Kuminov, A.A., Repnev, A.I., Vyushkova, T.Yu.,Perejaslova, N.K., Nazarova, M.N., Bazilevskaya, G.A. Modeling ofozonosphere response on solar proton event in November 1997.Geomagnetism i Aeronomy 41, 243–252 (in Russian), 2001.

Lacoursiere, J., Meyer, S.A., Faris, G.W., Slanger, T.G., Lewis, B.R.,Gibson, S.T. The O(1D) yield from O2 photodissociation near HLyman-a (121.6 nm). J. Chem. Phys. 110, 1949–1958, 1999.

Lary, D.R. Gas phase atmospheric bromine photochemistry. J. Geophys.Res. 101, 1505–1516, 1996.

Lee, L.C., Slanger, T.G., Black, G., Sharpless, R.L. Quantum yields forthe production of O(1D) from photodissociation of O2 at 1160–1170 A.J. Chem. Phys. 67, 5602–5606, 1977.

Lin, M.C., Bauer, S.H. Molecular reaction of N2O with CO and therecombination of O and CO as studied in a single-pulse shock tube. J.Chem. Phys. 50, 3377–3391, 1969.

Matsumi, Y., Kawasaki, M. Photolysis of atmospheric ozone in theultraviolet region. Chem. Rev. 103, 4767–4781, 2003.

Michelsen, H.A., Salawitch, R.J., Gunson, M.R., Aellig, C., Kampfer, N.,Abbas, M.M., Abrams, M.C., Brown, T.L., Chang, A.Y., Goldman,A., Irion, F.W., Newchurch, M.J., Rinsland, C.P., Stiller, G.P.,Zander, R. Stratospheric chlorine partitioning: constraints fromshuttle-borne measurements of [HCl], [ClNO3], and [ClO]. Geophys.Res. Lett. 23, 2361–2364, 1996.

Mount, G.H., Rottman, G.J. The solar spectral irradiance 1200–3184 Anear solar maximum: July 15, 1980. J. Geophys. Res. 86, 9193–9198,1981.

Nee, J.B., Lee, P.C. Detection of O(1D) produced in the photodissociationof O2 in the Schumann-Runge continuum. J. Phys. Chem. 101, 6653–6657, 1997.

Nicolet, M. Solar spectral irradiances with their diversity between 120 and900 nm. Planet. Space Sci. 37, 1249–1289, 1989.

Olsen, S.C., McLinden, C.A., Prather, M.J. Stratospheric N2O–NOy

system: Testing uncertainties in a three-dimensional framework. J.Geophys. Res. 106, 28771–28784, 2001.

Randall, C.E., Harvey, V.L., Manney, G.L., Orsolini, Y., Codrescu, M.,Sioris, C., Brohede, S., Haley, C.S., Gordley, L.L., Zawodny, J.M.,Russell III, J.M. Stratospheric effects of energetic particle precipitationin 2003–2004. Geophys. Res. Lett. 32, L05802, doi:10.1029/2004GL022003, 2005.

Roble, R.G., Dickinson, R.E. How will changes in carbon dioxide andmethane modify the mean structure of the mesosphere and thermo-sphere? Geophys. Res. Lett. 16, 1441–1444, 1989.

Rohen, G., von Savigny, C., Sinnhuber, M., Llewellyn, E.J., Kaiser,J.W., Jackman, C.H., Kallenrode, M.-B., Schroter, J., Eichmann,K.-U., Bovensmann, H., Burrows, J.P. Ozone depletion during thesolar proton events of October/November 2003 as seen bySCIAMACHY. J. Geophys. Res. 110, A09S39, doi:10.1029/2004JA010984, 2005.

Rood, R.B. Numerical advection algorithm and their role in atmospherictransport and chemistry models. Rev. Geophys. 25, 71–100, 1987.

Rusch, D.W., Gerard, J.-C., Solomon, S., Crutzen, P.J., Reid, G.C. Theeffect of particle precipitation events on the neutral and ion chemistry

of the middle atmosphere: I. Odd nitrogen. Planet. Space Sci. 29, 767–774, 1981.

Sander, S.P., Friedl, R.R., Golden, D.M., Kurylo, M.J., Huie, R.E.,Orkin, V.L., Moortgat, G.K., Ravishankara, A.R., Kolb, C.E.,Molina, M.J., Finlayson-Pitts, B.J. Chemical kinetics and photochem-ical data for use in atmospheric studies, JPL Publication 02-25, JPL,Pasadena, CA, 2003.

Solomon, S., Reid, G.C., Rusch, D.W., Thomas, R.J. Mesospheric ozonedepletion during the solar proton event of July 13, 1982. Part II.Comparison between theory and measurements. Geophys. Res. Lett.10, 257–260, 1983a.

Solomon, S., Rusch, D.W., Thomas, R.J., Eckman, R.S. Comparison ofmesospheric ozone abundances measured by the Solar MesosphereExplorer and model calculations. Geophys. Res. Lett. 10, 249–252,1983b.

Solomon, S., Rusch, D.W., Gerard, J.-C., Reid, G.C., Crutzen, P.J. Theeffect of particle precipitation events on the neutral and ion chemistryof the middle atmosphere: II. Odd hydrogen. Planet. Space Sci. 29,885–892, 1981.

Sonnemann, G., Felske, D., Knuth, R., Martini, L., Stark, B. How dry isthe thermosphere? Space Res. 17, 265–270, 1977.

Stief, L.J., Payne, W.A., Klemm, R.B. A flash photolysis–resonancefluorescence study of the formation of O(1D) in the photolysis of waterand the reaction of O(1D) with H2, Ar, and He. J. Chem. Phys. 62,4000–4008, 1975.

Summers, M.E., Siskind, D.E., Bacmeister, J.T., Conway, R.R., Zasadil,S.E., Strobel, D.F. Seasonal variation of middle atmospheric CH4 andH2O with a new chemical–dynamical model. J. Geophys. Res. 102,3503–3526, 1997.

Talukdar, R.K., Longfellow, C.A., Gilles, M.K., Ravishankara, A.R.Quantum yields of O(1D) in the photolysis of ozone between 289 and329 nm as a function of temperature. Geophys. Res. Lett. 25, 143–146,1998.

Thompson, B.A., Harteck, P., Reeves Jr., R.R. Ultraviolet absorptioncoefficients of CO2, CO, O2, H2O, N2O, NH3, NO, SO2, and CH4

between 1850 and 4000 A. J. Geophys. Res. 68, 6431–6436, 1963.Toumi, R. A potential new source of OH and odd-nitrogen in the

atmosphere. Geophys. Res. Lett. 20, 25–28, 1993.Watanabe, K., Inn, E.C.Y., Zelikoff, M. Absorption coefficients of oxygen

in the vacuum ultraviolet. J. Chem. Phys. 21, 1026–1030, 1953.Yoshino, K., Cheung, A.S.-C., Esmond, J.R., Parkinson, W.H., Freeman,

D.E., Guberman, S.L., Jenouvrier, A., Coquart, B., Merienne, M.F.Improved absorption cross-sections of oxygen in the wavelength region205–240 nm of the Herzberg continuum. Planet. Space Sci. 36, 1469–1475, 1988.

Yoshino, K., Esmond, J.R., Cheung, A.S.-C., Freeman, D.E., Parkinson,W.H. High resolution absorption cross-sections in the transmissionwindow region of the Schumann-Runge bands and Herzberg contin-uum of O2. Planet. Space Sci. 40, 185–192, 1992.

Zander, R., Mahieu, E., Gunson, M.R., Abrams, M.C., Chang, A.Y.,Abbas, M.M., Aellig, C., Engel, A., Goldman, A., Irion, F.W.,Kampfer, N., Michelsen, H.A., Newchurch, M.J., Rinsland, C.P.,Salawitch, R.J., Stiller, G.P., Toon, G.C. The 1994 northern midlat-itude budget of stratospheric chlorine derived from ATMOS/ATLAS-3 observations. Geophys. Res. Lett. 23, 2357–2360, 1996.

Zaragoza, G., Lopez-Puertas, M., Lopez-Valverde, M.A., Taylor, F.W.Global distribution of CO2 in the upper mesosphere as derived fromUARS/ISAMS measurements. J. Geophys. Res. 105, 19829–19839,2000.

Zhou, D.K., Bingham, G.E., Rezai, B.K., Anderson, G.P., Smith, D.R.,Nadile, R.M. Stratospheric CH4, N2O, H2O, NO2, N2O5, and ClONO2

profiles retrieved from Cryogenic Infrared Radiance Instrumentationfor Shuttle (CIRRIS 1A)/STS 39 measurements. J. Geophys. Res. 102,3559–3573, 1997.

Zipf, E.C., Prasad, S.S. Evidence for new sources of NOx in the loweratmosphere. Science 279, 211–213, 1998.