The neutral composition of the stratosphere and mesosphere

JOVW& of Atmospheric and Temeid

Physics,

Vol.37,PP.865to 884.Persamon Press,1975.Printedin Northern Ireland

!Phe neutral composition of the stratosphere and mesosphere JAMES C. ANDERSON and T. M. DONA~JE University of Pittsburgh, Pittsburgh, Pemsylvania 15260,U.S.A. Al&a&-Our present understandingof the factors that control the distribution of minor species in the mesosphereand stratosphereis discussed. Attention is devoted to the odd hydrogen, odd oxygen, odd nitrogen, sulfate and aerosol systems. The results of recent memurementsand a comparisonwith model calculationsare presented. Emphasis is on the portion of the atmosphere in which the distribution appears to be controlled by chemistry and vertical eddy transport. It is shown that reasonably good agreement between observation and theory now exists in the region above 60 km for odd hydrogen, nitrogen and oxygen systems,but that seriousshortcomings exis5 in our empirical knowledge of minor species and of the coupling between dynamics and chemistry in the stratosphere. INTRODUCTION During the past three years there has been a dramatie increase in the attention shown by atmospheric scientists to the problem of understanding the composition of the stratosphere and mesosphere. This interest, caused by ctonoern over the possible effects of pollution at stratospheric levels, is bringing together the previously loosely coupled disciplines of meteorology, chemical kinetics and aeronomy. The result so far has been at worst the meaningful formulation of the major problems and at best the apparent solution of some of them. DYNAldlCS In this review the complex dyna~e~-ehe~c~ system of the troposphere and lower stratosphere will not be discussed. We merely point out that in the troposphere the motion of the atmosphere may be taken to be composed of a meridional and zonal circulation and eddy motions that are deviations from the zonal averages. Stratospheric and mesospherio transport is often treated in model calculations by aeronomers in particular as though it were one dimensional (vertical) and could be described by ‘eddy mixing’ producing vertical fluxes of constituents in a manner rather analogous to molecular diffusion at low particle densities. In fact there is a regionat least in the lower stratosphere-where it is clear that there is a general ciraulation causing a distinct pattern of organized vertical and meridional motion and that there are regions where the stagnant barrier between stratosphere and troposphere called the tropopause scarcely can be said to exist. The behavior of ozone (Fig. 1) is the best sort of evidence for this situation.

Although ozone is clearly produced in the tropics as a consequence of 0, photolysis, the maximum vertical column concentrations occur at high latitudes. Clearly ozone is effectively transported poleward to a sink near the poles in a large vertical region of the atmosphere. A major question is at what altitude can the effect of this circulation be ignored and the problem treated as one of simple vertical diffusion and photochemistry.

The physical system to which we are addressing ourselves is one in which the surface of the Earth is the source of a number of gases that are stable in the lower troposphere, but are carried upward by vertical transport into the stratosphere and mesosphere where the chemioal environment is very different than it is near the Earth. The principal difference is that at stratospheric altitudes and above the atmosphere is highly oxidizing as a consequence of the photodecomposition of moleoular oxygen and the creation of product species such as atomic oxygen and ozone. Metastable excited forms of atomic oxygen also are present in large enough concentrations to play an important role in the chemistry. The principal constituents of the lower atmosphere that diffuse upward to be transformed into other interesting forms and on which we shall focus attention are the following: (a) Hydrogen compounds such as H,O, CH, and H, that rise upward through the troposphere and are photolyzed or react with oxygen allotropes in the stratosphere, mesosphere and lower thermosphere, there to be ohanged into such species as H, OH, HO,, H,O,, CO and CO,.

866

866

JAWS G.

Average

ANDEBBON

and T. M. DONAHUE

Variation of Total with Latitude

Latitude

Ozone

‘N

Fig. 1. Average varicttion of ozone with latitude.

(b) Nitrous oxide (N,O) and NH, that eventually are converted after initial reactions with OH and O(‘D) to NO, NO, and HNO, among other interesting nitrogen compounds. (c) HCl which eventually will be decomposed into Cl which in turn may react with ozone to form the oxide Cl0 as part of a series of reactions potentially important in the ozone chemistry. (d) SO, that emanates from volcanoes, rises and is transformed into layers of sulfates and aerosols at high altitudes. As we shall see these gases orginate from a variety of sources as products of organic reactions in swamps and rice paddies or as the result of outgassing, tectonic activity, or vulcanism. They are transported vertically and horizontally by the general circulation in the lower atmosphere where they may undergo heterogeneous chemical conversion. Ultimately they enter the stratosphere where eventually one may combine vertical flow described by eddy and molecular diffusion with photochemical production and loss processes. Of course the four categories of chemical species: hydrogen, nitrogen, chlorine, sulphur and their oompounds, may interact in important ways. Some of these interactions we shall try to identify and discuss. As we have pointed out, pollution problems have stimulated a dramatic increasein the interest atmospheric scientists have shown in the problem of understanding the composition of the stratosphere and mesosphere during the past few years. This interest has been stimulated by the need to understand the effect of emissions from supersonio jet airoraft and possibly other kinds of vehicles on ozone particularly.

The ozone problem has been with us for a very long time, ever since observations showed that the simple CHAPMAN(1930) removal scheme 0 + 0, -+ 20,

(1)

left more ozone than wss observed. The introduction by BATESand NICOLET(1950) of hydrogen catalytic schemes ending in O+HO,+OH+O,

(2)

O+OH+O,+H

(3)

and

still was inadequate to bring the calculated concentrations down to the observed ones. Desultory discussionof the possibilitythat the reaction of ozone and nitric oxide, NO +O,+NOs+O,

(4)

might resolve the difficulty can be found in conference proceedings before 1970 but it was CRUTZEN (1970) who first worked out a cycle involving odd nitrogen, reaction (4) followed by NO,+O-+NO+O,

(5)

that showed promise of f%nallysolving the photochemical problem. And it was JOHNSTON(1971) who dramatically drew attention to the possibility that serious reduction in 0, could be caused by NO emissions from large fleets of super-sonic transports flying in the stratosphere where residence times for pollutants is long. These early papers treated transport processes,horizontal and vertical, very approximately. Since transport exerts a decisive control over the global distribution of ozone below 28 km, the real consequences

The neutral composition of the stratosphere and mesosphere of artificial injection of odd nitrogen and the real explanation of the natural distribution and seasonal behavior of ozone remained obscure but for very practical reasons muat be determined. Fortunately, but fortuitously, aeronomy had developed by 1971 the techniques needed to attack with some confidence the problem of coupled flow and photo~hemist~ in a planetary atmosphere under very complex conditions at least where the flow could be assumed ss essentially vertical. This was so because of the need to understand the unexpected complexities found in the atmospheres of Mars and Venus where the problem of understsnding the stability of the CO, atmosphere of these planets and the vertical flow of hydrogen compounds was very challenging (DONAHUE, 1968, 1971). Techniques for handling the vertical coupled flow problem for those two terrestrial planets with molecular and eddy diffusion were developed rapidly, most conspicuously by MCELROY and his colleagues (HUX~EN and MCELROY, 1970; MCELROY and MCCONNELL, 1971). Those techniques were ready in 1971 to be applied to the mesosphere and stratosphere of the Earth. They were based on the method developed by COLE~ROVE et aI. ( 1965,1966) in the mid 1960’s to solve the problem of atomic oxygen recombination in the Earth’s atmosphere near 100 km. The crucial feature of this method is its use of the ooncept of turbulent or eddy diffusion and its reduction mathematic~y in a flux equation to a role analogous to that of molecular (Fickian) diffusion, with an eddy diffusion coeffifiioientthat produces flows of individual atmospheric constituents when there is a gradient in their mixing ratio relative to the ‘major’ species. Thus, where eddy diffusion dominates and the atmosphere is isothermal, the flux of a minor species of concentration [z] is given by

where [M] is the total particle con#ntration, fr is [~I~[~] and fi is the eddy diffusion coefficient. In more luxuriant detail, but still omitting several complexities, the flux of constituent i in the presence of molecular and eddy diffusion is determined by the differential equation

867

where Q is the molecular diffusion coe%oient for species d,&@“, = -d(e%[i])/dz is the aotual local scale height for species i, soi kT&g, a is the local average atmospheric scale height, and CL~ is the coefficient of thermal diffusion for species i. The flux equations must be solved in such a way that they satisfy the oontiRuity equations

-dA = pi dz

l$

where pc and 1, are appropriate production and loss terms, usually but not always chemical or photolyti~. One great obstaole to progress in solving many complex problems has been the lack of information concerning some crucial data defining pi and 1, at the appropriate temperature, even though the kineticists in the laboratory have been doing a labor of Hercules to supply them. Another great failing in many oalc~ations has been failure to impose and observe reasonable boundary conditions, as pointed out by STROBEL (1972a). Finally, there is the problem that in most treatments of the flow problem-those of the AECRL school moat notably excepted (KENESHEA and ~I~~~, 1970)--p, and Ii are taken to be time independent averages. One matter to be settled at the outset, if one wants to attempt to use the coupled flow approaoh to prediot minor constituent densities in the lower atmosphere, is to discover how K varies with altitude. Below the tropopau~ direct observation of the motion of tracers is possible. At higher altitudes some theoretical guidance is available for mixing length models from the work of NEWELL (1964), REED and GERM~LN(1965) and LINDZEN (1971). Experimentally, advantage may be taken of a dete~ation of the vertical profile of some tracer which is consumed by photochemistry but not regenerated. In this case pi vanishes identically. One such tracer is methane; NsO is another. EHHALT et al. (1972) have obtained data for the mixing ratio of CH, up to 50 km. The chemical scheme by which CHd reacting initially with 0 (‘D}, OH and sunlight is converted ultimately to CO, and hydrogen atoms without any known regenerative mechanism is shown in Fig. 2. Application of equations (7) and (8) with pi = 0 and a source of CBi, amounting to 3 x 1O’l cm-s se& at the Earth’s surface and arising from d~omposit~on of organic matter in swamps and paddy fields (ROBINSON and ROBINS, 1968) has led to a profile for H up to 50 km as shown in Fig. 3 (WOFSY and MCELROY,

JAXYBSG. Anmsnsoa and T. M. Dox~riux

888

Fig. 2. Methane reaction scheme in the lower atmosphere.

60 -

IO3 Eddy

I

I

I

104

I05

106

Diffusmn

Coefficient

(cm2sec-’

IO7 )

Fig. 3. Eddy coefficient deduced by (WOSSYand MCELROY,1973) marked ‘high’ compared to an earlier pro% (Worsv et al.,1972). 1973). Agreement between calculated and observed CH, concentrations is shown in Fig. 4. If K is extrapolated from 50 km following a [&fJ-1’2 law it comes out at 100 km to a vahre higher than is now compatible there with atomic oxygen or argon data (Fig. 5 from DONAX~~ et al., 1973). That is to say it tends to put the turbopause too high, the [0] concentrations too low near 100 km, and the [~]~~2] ratio too large at high altitude. Recently CUNNOLD et al. (1973) have suggested a modification of the profile for K near 16 km. Obviously further observations of the CH* density variation with altitude will be most valuable, as will further work on its photochemistry, for not only does the methane distribution provide us with information concerning vertical transport coefficients but CH, is also an important source of other atmospheric constituents in the mesosphere, such as hydrogen compounds, CO and CO, (MCCONNELL et al., 1971).

A major simplification in the anaIysis of the behavior of atmospheric constituents has been provided wherever there are atmosphe~c regions in which certain species interact chemically very rapidly compared with the rate at which they are created indi~du~y from or converted to other species. Then they may be treated in the coupled flow problem ss a single entity. Their individual densities may ult~a~ly be computed whenever they are needed, from photochemical equilibrium relations among their members. Thus odd hydrogen: [HO,1 = 131 -I- [OHI -t [HO,1

(9)

as ~stin~ished from combined forms of H such HsO, H2 and CR, may be treated in this way. So may odd nitrogen: [r\rO,l = INI + !301 -t [HNO,]

+ t37021 + IN027 4 2l32%,1 + CHNO,l.

(10)

889

The neutral composition of the stratosphere and mesosphere

WO O(W

I

-I- CK, -+ CH,

+ OH,

(13a)

(13b)

A d&ailed diagram showing &he chemical reaction scheme for hydrogen compounds is shown in Fig. 5. This aonstituent of planetary atmospheres is interesting not only because of the role it plays in the recombination of odd oxygen on Earth or CO and 0 on other terrestrial plane& It is also interesting because one sink for HO, is ssoape from the atmosphere into spaoe with all that implies for the evoluutionof planetary atmospheres and the presenoe of water in liquid or vapor form on the planet;s. So-oalled Jeans escape of atomic hydrogen from the base of the exosphere by atoms traveling upward with grea%r than escape veIocity in the tail of the Maxwelli.8 ‘A.. , * Boltzmm distribution has been long regarded &s controlling the loss of hydrogen from planets. Only wikhin the pas%few years-again for reasons related to oddities in the Martian and Cytherean environments-has carefulconsideration beengiven I.5 1.0 to the great variety of factors that control the CW Mixing Rotio Ippm) upward ftow and eventual es~pe of atmospherio 4 constituents (BXIKEMAX, 1969, 1971; DON;1IIWE, Fig. 4. CH, mixing ratio observed compared to that 1969; EWXTEN and MCELROY, 1970; HUNTEN, predicted for low, adopted (high in Fig. 3) and high, A, C rend B respectively, eddy diffusion coefficient 1973a, b). Thermal and nanthermal processes p&iles. can play important roles in escape in &heexosphere (MCEWXOY, 1972; MCELWY and DONARUIZ, Radical 1972; GOLIZ, 1966; TINSLEY, 1973). There are many potential bottlenecks for the outward Inlerchange Production L’S’ flow besides the well known one a% the critical OH ____------------L H,O level called the axobase, Recently HUXTEN OH 0 (1973a, b) has analyeed the controIling factors /-- 0 # O,H /’ ‘20 ,/6-I 1 carefully in an impotiant series of papers. He haa 03 o’a hv /’ ___‘_-< \ HO shown that there is a wide range of practical 0,O OH -., 10”’ 0 -. conditions in which the exobaso will accommodate ‘. L --\ HZ H ‘, 1 “u II / 02 any Aow of hydrogen it reoives from below and *____“_---_-“.---H H2 allow it to escape simply by 4.lowing the density O(b) to build up high enough. The real bottleneck Fig. 5, HO, rear&ionscheme, tends to OCCUFin the region near the 80 calfed turbopause where the amount of upward flux is as distinguished, say from N, or N,O. The conoept set mainly by the mixing ratio of hydrogen in of odd oxygen, particularly 0 and O,, is an old all forms at lower altitudes, the density independone. XII fact auf b&c problem is precisely how ent part of the molecular diffusion coefficient O,, created by photolysis, is destroyed. and looa scale heights. This can be seen from

I ‘r0

0

relations (6) and (7).

ODD HYDROGEN

Odd hydrogen in the stratosphere is produrxd mostly from the following processes (NICOW, I9704 O(%)

+ H,O -+ 20H

(11)

U(W)

+ H, *OH

(12)

+H

At low altitude where eddy

diffusion dominates normal fluxes will t&rate

no appreoiabfe gradient in& On tihe other hand the molecular diffusion contribution to the Aow is basically given by (14)

870 but B* = b,f[l@].

J-a

G.

ANDERSON

So this flux may be written as

(15)

and T. M.

DONAHUE

mixing ratios of H,O, H, and CH, at 50 km, the photolyxing solar flux and the exospheric temperature. They have also published curves showing the main production and loss rates for H,O, H, and HO, as functions of altitude together with the fluxes of H, Ha and HaO. (See Figs. 9 and 10 for examples and ss an aid in following the discussion in this section.) They have shown that, when Tc is greater than 800 K the upward flux of hydrogen will be 2 x 10’ crnmaset-r times the total hydrogen mixing ratio at 60 km in ppm. By the total mixing ratio we mean

where b, is altitude independent and fj,aa we have pointed out, will change little until the eddy flow becomes small compared to the molecular flow. According to his arguments the upward flow and escape rate should be determined mainly by fi for a given atmosphere as long as the e&ion velocity at the exobase set by the exospheric temperature is large enough, but could drop to very low values if that temperature were low enough. Dependence on details of chemistry, photolysis rates for HsO, and other factors should It turned out that H, was dominant in density be of secondary importance and the escape between 74 and 133 km and in the upward flux it flux for Earth should be almost independent of produced from about 83 to about 13Okm for the exospheric temperature above about 860 K. These remarks led HTJWEEN and STROBEX, large T,. Above 130 km Ha was converted to H by reaction with hot oxygen atoms in the tail (1974) and LIU and DONAH~J~ (1974a, b, o) to of the Maxwell-Boltzmann distribution. In the undertake detailed development of the coupled models of LIU and DONAHUE the mixing ratio flow problem for HO,, HsO, CH, and H, from the of H, at 50 km is set at O-5ppm and of CH, at mesopause to the base of the exosphere, It was 0.25ppm (EEEALT, 1974), some Ha0 mixing clear-and indeed has been clear for a long time-ratio assumed and the upward flux calculated. that the calc~ation of the ~st~bution of hydrogen There occurs a strong flow of Hz up from 50 km compounda in the mesosphere and lower thermoto a sink resulting from decomposition of H, by sphere must include the esoape flux as an integral O(l.D) and OH near 58 km. There is a large part of the calculation. That it was clear did not source of water vapour at 59 km as a result of necessarily mean that it was ever done. Clsssical the reaction calculations of the flow of hydrogen through the the~osphere and outward from the base of the OH: +HO,+H,O +O, (17) exosphere (MANGE, 1961; BATIGSand PATERSON, 1961; KOCEAIW and KICOIZT, 1962, 1963) and the water flows upward and downward from this source. CH, flows upward everywhere essentially assumed a fixed density of atomic and is converted to HO,. Two forms of HO,, hydrogen somewhere-100 km or the exobaseOH and HO,, are concentrated below 80 km. and derived a distribution of II sufficient to Above this altitude their density decreases maintain a given flow or else discovered that rapidly with altitude because of the tra~o~ation with a fixed density of H at the lower boundary the of HO, from H to HO, and OH depends on the flow was temperature dependent for suf&iently presence of 0,: low T,--the temperature at the exobase. The possible role of other forms of hydrogen such as H+O,-+OH-+-0, (18) H, on the flow have never been guantitatively and of 0, studied. HUWJYEN and STBOBEL (1974) have published a calculation of the densities of hydrogen II+-O,+~+HO,+M. (19) compounds from the stratosphere to the exosphere There is an important source of H, as a result of and established a relationship between the mixing the reaction ratio of hydrogen sources in the stratosphere and the (presumed) Jeans escape flux for one R:+HO,+H,+O, (26) set of conditions. Lm and DONAZXUX(1974a, b, cf have gone further and calculated ~stributions of at 82 km. Out of this source, H, flows upward HO,, CR,, H,O and H, from 50 km to the exobase to be converted to II by atomic oxygen above for a very wide variety of conditions involving 125km and downward to the O(‘O) sink near variation of the chemical rate constants, the 58 km. In the region between 58 and 82km

Temperature (K)

Fig. 6. Vari&ion of Jeans eecapeflux of hydrogenfrom Earth with exospherictemperature, Threecurve8are labelledin terms of eddy diffusionooefficients at 100 km in 10dcmpaec-l. is flowing downward Hz0 is ffowing unward from the OH-HO, aouree near 63 km to be destroyed %nally by photolysis above 82 km. Above 82 km photolytio de¬ion of H&I dominates reconve~ion of HO, to water vapour and the source for esoaping hydrogen develops. (Below 65 km decomposition of H&i by O(‘D) is much more irn~o~&nt than photolysis for destruction of H,O and creation of HO,). Some of the atomic hydrogen oreated from H,O and R, flows up to the exobase to escape and some goes downward to be converted to other forms of HO, or to recombine with HO, and form Lf,, At 90 km the flow of atomio hydrogen reverses, The dominant hydrogen& speeiee between 133 and 79 km is H,. Bowever, only 3.6 ppm of R&I at 50 km were found niece to produce a %ux of 7 x 10'cmBa sea-l. And as Hunten predicted, it proved very difficult to budge this relationship. The essential validity of &mien’s principle that the mixing ratio of hydrogen in the lower atmosphere controls the escape flux for a Bpecifioplanetary atmosphere and large T, seems well established. When T, is below 800 K the density of atomie hydrogen became 80 large trying to maintain a given finx at the exobase that the ainkrepresented by reaotiou (20) begau to limit the attainable densities of H at 1OOk.r~ and hence the esoape flux associated with a given mixing ratio. Under suoh conditions the ET created from IT,0 photolysis and reaction of H, with 0 Gould not eseape rapidly and most uf it began to flow down to the 90 km level to recombine with HO, and form

where H,

H,. The altitude at which the H %ux reverses was found to move upward with reduced T, and the e~ape flux found to drop (Fig. 6). Apart from giving density pro%l~ for hydrogen species down to 60 km these c~eu~ations showed that the escape flux of atomio hydrogen from Earth mu& fall between 16 x 10’ a.nd 30 x 107 cm+ aeo-1 if the total hydrogen mixing rate at the stratopauae &XI between 9 and X7 ppm and that the escape flux must be independent of T, above 800 K. The mixing ratio corresponds to H,O values between 4 and 7.6 ppm aa measured by MASTENBROOK (1968). The measured Jeans escape %ux by VIAL ~WADUR et ai, (X974), by BERTATJX (Ii'@%) and deduced long ago by DOXAEUE (1966) is closer to 5 x IOrem-” at 1000 K than to these large vahse~~ This disorepancy led Lru and DONAIGX (1974a) to suggest either that the BASTEBEROOX (1968) values were muoh too high or that other important mechanize for hydrogen escape mn& exist. These were found in lateral flow to supply the polar wind and-most importtlntly as COLE (1966) and TINSLEY(1973) suggested-by creation of fast H atoms following H++O+HfO+

(2X)

in the exosphere, A cakulation of the magnitude of this charge exchange flux showed that it was very large. Furthermore it should deorease with T, since the hydrogen content of the exosphere should decrease with increasing T,. Thus the

JAMES G. ANDERSON

872 Table

1. Hydrogen fluxes 107 cm-2 set-1

in units

of

and T. M. DONAHUE Jeans

flux

ought

to increase

so as to maintain Predictions

a total

960° 1000” llooO 1200” 1500° 1900”

2.6 3.67 5.0 7.05 8.7 13.5 18.2

22.2 21.2 20.0 16.6 13.5 8.9 5.6

1.4 1.9 1.8 2.9 3.6 4.4 2.9

(Lm

and

show

the

required

DONAHUE, densities if

the

dependencea

1974b). of

HO,,

total

and

Jeans This

6.4 ppm

flux

at

flux

H,O,

1

7 and

8

H,

and

mixing

CH,

ratio

is

[0.5 ppm H,, 0.25 ppm

as it ought is

to be if the

5 x 10’ cmm2 se&.

such a Jeans

densities

of

HsO] 1000 K

is because

spheric

T,

of T,.

in Table

Figures

hydrogen

14.8 ppm at the stratopause CH,

increasing

are shown for the values of the various

flux and their temperature 900”

with

flux independent

flux

calls for exo-

that result in a charge

20 x 10’ crnm2 see-l

and

exchange

an

average

flux to support the polar wind of 1.8 x 10’ crnp2 set -1 - 26.8 x 10'cmp2 set-’ in all. The fluxes of individual duction Fig.

species

are shown

and loss rates

10 (LIU and DONAHUE,

The density Fig.7 depend and

(20).

tegrated

proflles

In

1971b) above

Fig.

11 we

in

shown in

chosen for (17)

compare

observed

of OH

levels with

in-

(ANDERSON,

those predicted

of rate constants

refer to the reaction

k,, and

numbers in

It can be seen that very low values

of k,, and k,, would been measured the

pro-

1974c).

densities

specified

A).

9 and and H,O

for OH and HO,

combination

k,, (the subcripts Appendix

H,

on the rate constants

or column

for various

in Fig.

for HO,,

apportionment

three dominant

demand

more

by Anderson. of

odd

OH than has

The reason is that hydrogen

among

its

forms is given by

[HI -= [H&l &CO1 Density

~5021[~1

(cm-‘)

+ &l [O21(~,[021[~1

+ ~2[021)/k,[01

(=a) Fig, 7. Distribution of odd hydrogen in an atmosphere with fn = 14*8 ppm and 1000 K exospheric temperature .

[OHI -=[J3O,l

WI [HO21

W32lPfl

+ ~,[%I &KY

60 104

IO6

IO8

10’0

Density (cmm3) Fig. 8. Densities of H,O.

H,,

CHI under same conditions as Fig. 7.

(22b)

The neutral composition of the stratosphereand mesosphere

varies as the square root of the rate constant k,, in the region from 50 to 70 km where the OH-HO, reaction is the dominant sink for HO,. The larger the mixing ratio of total hydrogen-HzO, CH, and Hz-the larger is the value of k,, needed. It would appear that the indicated value lies somewhere between 2 x 1O-1acm3 se& as measured by HOCHENADEL et al. (1972) and 2 x 1O-11 cm3 se@ which is the value used for the curves labelled ‘low k’. The reaction between H and HO, forming H, is also important indirectly in controlling the OH concentration as is apparent in the relations (22) and (23). The so-called small value (NTCOLET, 1970a) is

I40

120

? f

too

3 .X z 80

k,, = 5 x 10-12T1’2 exp ( -1000/T)

60

while the ‘large value’ 1974) is

-I

IO')

IO' FIUK

IO9

(cm-*set”’ 1

Fig. 9. Constituent fluxes under same conditions as Fig. 7. Solid lines indicate upward fluxes and dashed lines downward fluxes. while the overall production and loss set its total concentration through PO,l’ =

873

2J,,,IH,Ol + 2k*[O?D)ICH,O bKW[HO~1

Thus, the concentration

+ H, + 2CH,l

+ bFV/[HO,l

’ (23)

of both OH and HO,

1%,,= 4.2 x lo-‘f

(24)

(GARVIN and HAMPSON, exp (-350/T).

(251

In Fig. 12 we have compared the Jeans escape flux as it depends on T, acaording to these models (LITJ and DONAHUE, 19740) with the measurements of VIDAL-MADJAR et al. (1974) and BERTAUX (1974). The agreement seems to be satisfactory. At the moment the problem of hydrogen photochemistry, flow, and escape appears to be in fairly good shape and there is satisfactory agreement between the escaping flow of hydrogen implied by observations of sowxx constituents of the stratosphere and mesosphere.

Production ond Loss Rates (cM3sec-‘) Fig. 10. Principal reactions for production and loss of HO,, H,O and HB (See Fig. 7). The numbers refer to reactions listed in Appendix A. Reaction rates and not production and loss rates are plotted exoept for Ep and CZ. Solid lines are for production reactions, dashed for loss.

JAMES G. ANDIER~ON and T. M. DONAEVE

874

I

l

x

kzs

hiph k,,,

high

hipk k,,,

low kt3

d,

low k,,,hiqh

o

low k,,.

kg3

low k2,

60 -

Column Densitykm-*1 Fig. 11. Comparisonof computedand observedOH column densities. ANDERSON’S (1971b) ob&vations &e indicatedby+- -I. 12

.,

,

I

t /

-

i

7

‘O-

This spsoies (NO,.) is produced by oxidation of N,O, nitrous oxide, resultingfrom nitrogen fixation by bacteria in soils (BATES and HAYS, 1967; MCCONNELL and MCELROY, 1973; NICOLET, 1970b; GEORGII, 1963; SCHUTZ et al., 1970) O(‘D) + N,O -+NO

-I- NO

(26)

(However, most of the N,O ia simply photolyzed to N, and 0.) This process demonstrates the dramatic role played in the chemistry of the lower atmosphere by metaatable atomic oxygen that is created in ozone photodecomposition 0, f hv --t 0, 4 O(lD)

(27)

and is present in mixing ratios aa low as lO-1g at 20 km because of its rapid deaotivation. CADLE (1964) and HAIWSON (1964) first Tex.(“K) recognized the importance of this species that Fig. 12. Jeansfluxesplotted&sfunctionsof exospheric had always been dismissed previously as hopetempemture. Solid line is that calculated by LIU and DONAH- (1974c), dashed line measurementsof lessly ineffectual in the stratosphere because of VIDALMADJAR et al. (1974), dotted line measurements its low concentration. Other potential sources by BERTAUX(1974). of NO, are NH, (but see KAPLAN, 1973) and ionization of N2 by cosmic rays followed by LIIJ and DOIUHUE chose 50 km aa their lower production of N(eD) in the conrse of the ion boundary because they left NO, chemistry out tr~sfo~~tion and r~ombination process (WAXof their chemical scheme and assumed an 0, NECE, 1972; RUDERMAN and CHAMBERLAIN, distribution. To go lower on this basis would 1973). This process followed by be very dangerous. Obviously a marriage of the N(zD) +O,-+NO $0 (28) models about to be discussed (Fig. 19) that include NO, and the Pittsburgh models of Figs. 7 in competition with and 8 is needed. One can note some inoonsisten~iss N(*S)+NO-+N,+O (29) where they overlap. The Liu-Donahue model contains oonsiderably more OH and HO, than the is the source of the thermospheric NO (BAXTE, 1966; MEIEA, 1971) that is transported to the MCELROYef al model. 900

1000

1100

I200

1300

JAMES C. ANDERSON tand T. M. L)ONA~UE

876

the energy source that seems to convert preciable fraction into

NO

of the atmosphere

during

these events

an ap-

30

near 100 km

(DONAXXUE, 1972),

2s

but it should always be kept in mind that there is a potential that

could

high latitude,

alter the NO,

high altitude budget

under

source certain

oonditions. To date the most elaborate attempts NO,

distributions

sphere

using coupled

of McElroy included

and

flow

the

and

et al.,

1974).

boundary

density

of NO

are those

group

Wofsy

(MCCONNELL and

McEnno~

and meso-

techniques

Harvard

McConnell

spicuously

to model

in the stratosphere

that

con-

MCELROY,

They

has

most

set

their

1973; upper

and flux to agree with

IE

the Meira data and include the N(*S) sink for NO above 70 km.

They use the N,O

surface as we have alresdy the conversion

and

by assuming

1973;

JUN~E,

0

to HNO,

a lifetime

against rain-out and wash-out MCELROY,

IE

and treat

of other forms of [NO,]

as a sink for [NO,] HNO,

source from the

indicated,

for

(MCCONNELL

1963;

ROBINSON

NO,

Number

Density

(cm-“)

15. NO, number density predicted by MCELROY et al. (1974) compared with observations by ACKFRMAN and MULLER (1973). Fig.

and ROBINS, 1968) of 5 days at 5 km decreasing exponentially their

latest

HO,

and

0,

toward

ground

treatments

they

creation

and

level. have

In

one

included

destruction

of the

self-con-

sistently and have arrived at the results shown in Figs.

14 and

15 for NO and NO,

It can be seen that agreement

mixing

ratios.

with Ackerman’s

data for [NO] was fairly good in these calculations provided

the

photodissociation

of

HNO,

assumed to vanish at long wavelengths. with [NO,]

data

was

Agreement

was rather less satisfactory

at

low latitude no matter what the long wavelength photolytic be.

absorptivity

of HNO,

was assumed to

More recently, however, the group appears to

have modified

its eddy diffusion model

(WOFSY,

1974) near 16 km following a suggestion of CnNNoLD et al.

(1974)

agreement [NO],

[NO,]

and 17.

and

to

between

achieved

have

observation

and [HNO,]

and

as shown

very

[NO].

There

for

in Figs.

There is one serious problem,

concerning

good

theory

16

however,

are measurements

that

give high values for [NO] above 20 km (ACKERMAN et al.,

1973 and FABMER, 1974) and these agree

with

the

model.

The

the Jet Propulsion call for an NO

latest

Lab data

density

lying

2.7 ppb from 11 to 16 km. give conspicuously 24 km. depends 2100A

1.2 and

There are others that

the

exact

concentrations on the

between

of

1974)

lower densities between 20 and

Furthermore

predicted

interpretation (TOTH et al.,

with

quantum

yield

course

of

of HNO,

the still

altitude

above

(see JOHNSTON, 1974).

The results of the model calculations of MoEnnov et al. NO

Number

Density

(cm-3)

Fig. 14. NO number density predicted by MCELROY et al. (1974) compared with observations by ACICERMAN et I%?. (1973).

(1974)

shown

for various

in Figs.

18 and

minor 19.

constituents

Many

of those

are in

Fig. 12 have still to stand the test of comparison with these

observed

densities.

comparison

will

Most be

that

important with

OH.

of all For

a77

The neutralcomposition of the stratosphere s;ad mesosphere

NO

Number

Density

NO,

(cm-‘)

Number

Density

(cm’3)

Fig. lB(a, b). NO, and NO number densities calculated (Wora~, 1974) and observed. Data are closed circles with error bars ACKERMANet al. (1973); Crosses and asterisks, RIDLEY et al. (up and down legs ( ); Cross hatching LO~ENSTEM el al., 1974). The result of T~TH et al. (1974) giving a mixing ratio of NO of about 3 x lo- lo from 11 to 16 km ;&renot plotted. They would lie between l-2 and 2.7 x 108 cm-S_

and OH -I- NO, f M + HNO, + M(k,,), and the catalytio destruction of 0,

(36)

(5) and (6)

giving ENol=

W’,I

HNO,

Mixing

Ratio

(V/V)

Fig. 17. HNO, Mixing Ratios calculated (MCELROY et al., 1974) and observed. Date are open circles: REXHE et al. (1969); open squares: WILLIAMS et aZ. (1972); Ieft cross hatching, LAZA.BUS et al. (1972); Right cross hatching, HARRIES (1973); closed circle, closed squares, triangles and plus marks, MURCRAY et al. (1973). Recent observetions by GIRARD (1974) from about 12 to 28 km seem to agree well also with the model.

reduced to its baldest form the entire photochemical scheme for [NO,. can be put in terms of two processes. These are creation and destruction of HNO,

taking into acoount the reactions OH + HNO,

-

H,O

-I- NO,&,)

(34)

JNOZ -t- MO1

w?&l.

-

(36)

The key role of OH is obvious in (33) as is the value of JflNOa. Work to establish the density of the one and the efficiency of the other should receive the highest priorities. McElroy and his oolleagues have obtained steady state 0, profiles (30’N latitude, 12’ solar declination) as a result of their calculation. The models along with measured values are shown in Fig. 20. (Note that according to the criterion of transport versus photoohemicalcontrol the calculated values are shown only to 28 km.) The NO, assisted recombination of 0, does appear to succeed well in explaining the former discrepancy below 50 km. Curve C is for the Chapman chemistry alone, curve B includes the HO, reactions of Bates and Nicolet and curves A and D are results of the model involving NO, with different values for the rate of reaction (4). It is not the purpose of this review to go into the consequences of artifiaial injection of NO, and HO, at various altitudes. We only note that the results of MCELROYet al. (1974), agree qualitatively with the earlier projections of CRUTZEN (1970) and JOHNSTON (1971) that the effects on 0, concentration are potentially very

878

JAMESG. ANDERSON

IO6

10’

and T. M. DONAHUE

IO9

IO8 Number

Density

IO'O

(cmm3)

Fig. 18. NO, densities calculeted by MCELROY et al. (1974).

60

Fig. 19. HO, and other densities calcu&ed by MCELROYet al. (1974). serious for some standard models of SST traffic. In this connection we would like to draw attention to an elegant analytical treatment of the artificial source problem by Hunten. He points out that the solution of (6) is (37) The atmosphere from 0 to 15 km can be regarded aa a region of efficient mixing (K z lo5 cm2 see-l). At 15 km, the tropopause, K drops to the low value of about 3 x lo3 cm2 see-’ over a rather large height range. HUNTEN (1974) emphasizes that it is this stagnant region above the tropopause end not a mysterious barrier at the tropopause that leads to the long residence times in the stratosphere and related effects that depend on

the height above the tropopause at which a constituent is injected. With constant K, the solution to (37) is

fi = A - WWfl

(33)

[i] = A[M]

(39)

and - +JK.

If & is constant, different values of A, the integr&ion constant, will prevail in the two regions of different K above and below the tropopause. If a souroe is assumed to exist at some altitude above the tropopause from which a constant flux goes downward and none goes upward, fi will be constant above the source level and decrease downward with [M] increasing and c#*negative. The solution below the tropopause, where K is large, is such that the value of [i]

879 simhr tea tha WC, 530~~8 from 8ST’s might seriously thre&en. the 0, fapr, The pr+~nt plans for the Space Xhuttle, for example, call for the we of 8 pcsmhlorate a&d fi%l whose combustion product ineludes ffCl. Vary mxdy (RQWLAND and MQLIN*A, 1974) have drawn attentian to m potentially serious and insidious source of stratospheric:C‘I as a consequence of phofoy&S above 30 km of ~h~~ro~~or~m~tha~~s CFCls and CF@, (Freous) now being r&+ased in the troposphere from spray oans and refrigeration u&s. A oontinued study af Cl chemistry involving constituents of the mesosphere and stratosphere is strongly to be encouraged.

Among the mom s%rt&ng discover& cou~~ning the oomp~sition of the mesospharrsmade durmg the pa& few years wzt$ the ~bs~~atio~ by a photometer aboard %h~000-8 aat&te of a very dense layer d particles that eohects h a layer Ies~ than 5 km wide over the geographic pde &ring looal Summer (DONARUEand GWXWYCHE~, 1973). A typical prowls of the slant radianoe produced by t&o layer and observed by the photomarer is shown in l?ig. 21, A typical variation in the m&mum radiance of’ a layer observed during a travemal of the pafar cap in two colors k alzo-wm in Rig. 22. ‘I’ba average altitude of the layers is 84-3 km. They appear over either pole during the

YELLOW Latitude 66.9’ Sclor 2 64’ 175 my, I969 10: es UT

880

JAMEScf. ANDERSONand T. M. t80"

DONAHUE

Figs. 7 and 8 the density of H, at 85 km would normally be 8 x I@ omw3, of H,O about 7 x IO’ cm-’ and of H about 10’ ome3, giving a total concentration of 2H of only lo0 ome3. Another way of stating the dBlculty caused by these observations and this interpretation is that the water vapor mixing ratio represented by the ice particles would be between 70 and 20 ppm by volume, or a total hydrogen mixing ratio of 140 to 80ppm. Hence an efficient transport to a cold trap at the polar summer mesopause might be indicated by these results. They show a charaoteristic buildup time of only about 5 days. SULPHATE AEROSOL LAYERS

Aerosol layers exist in the stratosphere that have been the object of extensive investigations from the ground (VOLZ and GOODY, 1962; FIOCCO and GRAMS, 1964; LAZARUS et at., 1971) 20:47-20:58 UT and sampled by devices carried on aircraft (FRIEND , 1966) and GANDRUD and LAZARUS (1974). Layers O0 Fig. 22. Maximum slsnt radiance observed by the exist near 24 km and at least up to 37 km. F’RIE~ OCO-6 air glow photometer at 5577A and 5890 A (1966) and CABLE and POWERS (1966) find these plotted perpendicular to the traok of the line of sight layers to consist largely of ammonium sulfate at 90 km. and persulfate. The most likely origin of the appropriate season. At low latitudes their radiance sulfates is oxidation of SO, rising from volcanoes. Concentrations are found to vary considerably and frequency of occurrence correspond to those from year to year, presumably because of variation of noctiluoent clouds. They first appear 15 days in vulcanism. before the solstice. The probability of their being observed reaches about 33 per cent 65’ CONCLUSIONS and 70” latitude by serial day 190, 60 per cent between 70’ and 75O by day 190 and saturates at Some sweeping conclusions are obvious. 100 per cent above 80° at about day 170. If, as (I) A massive attack should be continued on seems very likely, these layers are daytime the problem of understanding stratospheric and mesospheric circulation. The latter in particular manifestations of the phenomena called noctilucent clouds in the twilight, and have the same optical needs at least to get started. One goal of this properties (WITT, 1960, 1969) we may investigate study should be to develop simplified methods for coupling chemistry and transport similar to the the consequences. Analysis of the photo-polaripresent vertical eddy diffusion approach if that metric data for noctiluoent clouds show that is possible. A part of this study should be an those data are consistent with the particles in the observational program designed to obtain the clouds being spherical ice particles 1300 A in latitudinal and seasonal (if not diurnal) disradius. Their density at low latitudes is about tribution of minor species throughout the meso1 cme3 in a layer about 0.75 m wide (FOOEL and sphere and stratosphere. We admit that the latter REES, 1972). The satellite results, interpreted on program may not be practical until the shuttle the basis that similar conditions apply for the layers observed over the sunlit poles imply flies with a space lab carrying an atmospheric science facility (Scientific Uses of the Space particle densities as high as 50 omB3 if the layers Shuttle, 1974). are 1 km thick and 15 ornm3if the layers are 5 km (2) Measurements of the concentration of key thick. Since each particle would contain 2.7 x lOa minor species throughout the stratosphere, mesoH,O molecules if it is 1506 A in radius, the water sphere and upper troposphere are crucial. The tied up in these cIouds would be between 13 and measurement problem may be viewed in two 4 x log omm3at about 85 km. According to the parts (a) determination of the chemical source model of hydrogen compounds presented in

The neutral composition of the stratosphere and mesosphere

functions which require knowledge of the concentration of the stable species which diffuse upward through the troposphere from the planets surface, most notably H,O, IX,, CH,, N,O and HCl whioh are generally in the part per million range (the KC1 concentration may be significantly less) and (b) the concentration of atomic and radical species which play the central role in the reactive ohemical cycles, most notably 0(3P), O(lD), OH, HO,, NO, NO,, Cl and Cl0 which have concentratious in the part per billion to part per Tremendous progress has been trillion range. made recently in the me~~ement of the stable species CH,, H, and NsO as was previously mentioned. In addition the principal sink for odd hydrogen and odd nitrogen, HNO,, remains very important and its altitude and latitude dependence should continue to receive study. (3) Certain reactions with their temperature dependences (in the proper range) ought to be given high priority in laboratory studies. The key reactions are OH

+HCX-+HsO

-l-Cl

ACXERXAN M.snd FRIMOUTD. ACKERMAN M.and MULLERC. ACKERMANK~~~MULLER C. ACKERMANM.,FONTANELLAJ.C.,FRIMOUTD., GIRARD A.,LOUI~NARD N.,MuLLERC. and NEVEJANS D. ANDERSONJ. G. ANDERSONJ. 0, ANDERSONJ.~. ctndKAUFMAN F. ANDERSON J. G.,MAR~ITANJ. J. tend KAUFIVIANF. BARTH C.A. BATES D.R. and NICOLETM. BATES D.R.&~~PA~E~oNT.N.L. BATEsP.~II~HAY~P.B. BRINKMAXXKT. BRINKXANN R. T.

CADLER.D.~~~POWERSJ.W. CADLXR.D. CHAPMAN& CICERONE R.J.~~~STOLARSKIR.S. COLE K.D. COLEQROVEF.D.,HANSON W.B.,and JOHNSONF.S. COLEOROVE F.D..JOHNSON F.S.,zu~d HANSONW.B. CRUTZEN P.J. DEM0REW.B. DONAEUET.M. DONAHUET.M. DONARUET.M.

881

OH~~H~~H~O~~s OH -+- HNO, -+ HsO -I- NO, OH-l-SO,-+-M+HSO,$N OH +HOs+H,O

-1-0,

HO,+0,-+OH+20a HO, + H -+ ZOH; H, -I- 0,;

H,O + 0,

HO,+O+OH$O, HO,+NO~OH+NO, c1+0,+c10+0, Cl -i- CR, --, HCl +- CH, CI+H,-+HCl+H. (4) The time dependence of changes induoed in natural constituents of the stratosphere and mesosphere should be studied with care at both sunrise and sunset as their kinetic behavior under perturbed conditions hold the key to questions hidden by steady state measurements. Acknowledgements-This mork Fyas supported, in part, by the National Science Foundation, Atmospheric Sciences Section, Grant GA-37744X.

1969

1972 1973 1973

Acad. R. Be&. RuEI. CEasse Sci. 55, 948. Nature, Land. 240, 300. Pure Appl. Geophys. 100, 1325. Nature, Land. 245, 205.

1971a 1971b 1973 1974

J. geophys. Res. 76,4634. J. geophys. Rec. 76,782O. C%m. P&8. Lett. 19, 483. J. them. PhyS.60,3310.

1966 1950 1961 1967 1969 1971e

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p. 89.D. Reidel, Dordrecht-Holland. !l'elEus 18, 176. If&. Faraday Sac. 57,66.

1966 1964 1930 1974 1966 1966

J. geophys. Res. 70, 4931.

1966

J. geophya. Rea. 71,2227.

1970 1973 1966 1968 1969

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Nature, Land. 211, 1335.

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332

JA.MESQ. ANDERSON and T. M. DONAE~E

DONAEXJET. M. DONAHUE T. M. DONAHUE T. M., UDENTHER B. and BLAMONT J. E. DONAEIIII T. M., GUENTHER B. and THOMU R. J. DONAHIIII T. M. and GUICNTHERB. EEEALT D. H. EHEALT D. H., HEIDT L. E. and MARTELL E. A. EVANS W. F. J., HUNTEN D. M., LLEWELLYN E. J. and VALLANCE JONES A. FARMER C. B. FIOCCO G. and GRAMS G. FOQEL B. and REES M. H. FRIEND J. P. GANDRUD B. W. and LAZARUS A. L. GEORQII H. W. GOLDMAN A., MURCRAY D. G., MTJRCRAYF. H., WILLIAMS W. J. and BONOMO F. S. HARRIES J. E. HILSENRATH E., SEIDEN L. and GOODMANP. HOCHANADEL C. J., CHROMLEY J. A. and OQREN P. J. KOCKARTS G. and NICOLET M. HUNTEN D. M. and MCELROY M. B. HUNTEN D. M. HUNTEN D. M. HUNTEN D. M. and STROBEL D. HUNTEN D. M. JOHNSON F. S., PURCELL J. D., TOUSEY R. and WATANABE K. JOHNSTON H. S. JOHNSTONH. S. JUNUE C. E.

1971 1972 1972

J. atmos. Sci. 28,896. Radio Sci. 7, 73. J. atmos. Sci. 29, 1205.

1973

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1973 1974 1972 1968

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1974 1964 1972 1966 1974 1963 1970

Can. J. Chem. J. atmos. Sci. 21, 323. J. geophys. Rea. 7’7, 720. Tel1u.e18, 466. Tram. Am. geophys. ‘Un. 55, 383. Atmos. J. geophya. Rea. 68, 3963. Nature, Lond. 229, 443.

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Nature, Lond. 241, 515. J. geophys. Res. 74, 6873. J. Chem. Phys. 56, 4426.

1962 1970 1973a 197313 1974 1974 1952

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1971

KAPLAN L. D. KAUFMAN F. KENESHEA T. M. and ZINMERMAN S. P. KOCKARTS G. and NICOLET M. KRUEUER A. J., HEATH D. F. and MATEER C. L. LAZRUS A. L., GANDRUD B. and CABLE R. D. LAZRUS A. L., GANDRUD B. and CADLE, R. D. LINDZEN R. S.

1973 1969 1970 1963 1973 1971 1972 1971

LIU S. C. and DONAHUET. M. LIU S. C. and DONAHUE T. M. LIU S. C. and DONAHUE T. M. MANQE P. MA~TENRROOKH. J. MCCONNELL J. C., MCELROY M. B. and WOFSY S. C. MCCONNELL J. C. and MCELROY M. B. MCELROY M. B. MCELROY M. B. and MCCONNELL J. C. MCELROY M. B. and DONAHUE T. M. MCELROY M. B., WOFSY S. C., PENNER J. E. and MCCONNELL J. C. MEIRA L. G., JR. MIJRCRAYD. G.. KYLE T. G.. Mrnrcaa~ F. H. and WILLIAMS W. J. MURCRAY D. G., GOLDMAN A., CSOEKEPOECKH A., MURCRAY F. H., WILLIAXS W. J. and STOCKERR. N. NEWELL R. E. NICOLET M.

1974a 1974b 1974c 1961 1968 1971

Science 173, 517. J. Phys. Chem. 78, 1, 1974. Air Chemistry and Radioactivity. Academic Press, New York. Pure Appl. Geophys. 109-108, 1341. Can. J. Chem. 47.1917. J. atmos. Sci. 27,-831. hds B6ophys. 19, 370. Pure Appl. Gwphys. 103-108,1264. J. geophys. Rw. 76, 8083. J. Appl. Met. 11, 389. Mwospheric Model8 and Related Experiment8 (Edited by G. Fiocco) p. 122. D. Reidel, Dordrecht, Holland. J. atmos. Sci. 31, 1118. J. atmos. Sci. 31, 1466. J. atmoa. Sci. 31, 2238. An& GBophys. 17, 277. J. atmos. Sci. 25, 299. Nature, Land. 233, 187.

1973 1972 1971 1972 1974

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1971 1968

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1973

J. geophys. Rw. 78, 7033.

1964 1970a

Pure Appl. Gwphys. 58, 146. Planet. Space Sci. 18, 11 Il.

1963

The neutral composition of the stratosphere and mesosphere

NICOLETM. NORTON R. B. and BARTH C. A. REEDR.J.&~~UERXAXK.E. RHINEP.E.,TDBBS L.D.and WILLUMSD. RIDLEYB.A.,SCHIFFH.I., SHAW A. W., BATESL.HOWZETTC.,LEVAW:H., MEOILL L.R.,ASEE~EELDEBT. E. SCEXJTZK.,JU,Y~EC.,BECKR. and ALBRECHTB. STOLARSKIR.~~~ CICEZOXER. STROBELD. STROBELD.,HUNTEND.M.~~~MCELROYM.B. STROBELD. STROBELD. TINSLEYB.A. ToTER.A.,F~;~zERC.B.,SCH~~D~R.A. andRApEx0.F. VIDALMADURA.,BLAX~ONTJ.E.~~~ ~~~PHISSAMAYB. Vo~zF.E.and GooDYR.M. WARNECKP. WILLIAXSW.J.,BROOKS J.N.,M~RcRAY D.G.,MuRcRA~ F.,FRIED P.M.rtnd &~~WEI~~J.A, WxnG. WITT G.

WOFSY S.C.,MCCONNELLJ.C.~~~ McELROYM.B. WOFSY,S.C.~ndM.B.M~E~oy WOFSYS.C.~~~M~ELROYM.H. ZIPFE.C.,BORSTW.L.~~~~DONAH~ET.M. Reference is alao made to the followiltg unfiliahed

1973

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1970

J. gwphys.

1974 1972a 1970 1971 197213 2973 1974

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1974

J. geophys. Rea. 79,233.

1962

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197Ob

1970 1965 1969

1972 1972

1972 1974 1973 1970

Can. Jour. Chem. 52, 1682. J. geophys. Res. 78, 2619. J. geophye. Res. 75, 6371.

material:

1974

CUNNOLD D.M.,ALYEAF.N.,PHILLIPsN.A. ~~~PRINN R.G. FARMERC.B.,RAPEX

O-F., RoTRRA.

Res. 75,223O.

J. gwphys. Res. 85, 925. Spats Besearch IX (Edited by K. S. W. CHAMPION P. A. SMITH and R. L. SMITH-ROSE) p. 157. North-Holland, Amsterdam. J. geophya. Res. 77, 4477.

1960 1969

1974

BERTAUXJ.L.

883

1974

1973

and SCHINDLER R. A.

GARVIN D.~II~HAMsoNR.F. GIRARDA.

1974 1974

HAMPSON 3.

HER~uW.S.~~~BORDE~T.R.

1964 1967

KAUFMAN F.

1968

LO~XZNSTIZINM., PADD~OK J. P., Popover I. G. and SAVAOE H. F.

1974

ROBINSOW E. and ROBBINS E. C.

1968

L'hydrogeneatomiquedans I'exosphere terrestre: measures d’intensite et de largeur de raie de l’emission Lvmen-Al&e a bord satellite OGO-5 et int~~~t~tion. Ph.D. Thesis, L’Universite de Perk. Mea.snrements of Nitrogen Dioxide from Concorde 002. Presented at Third CIAP Conference, Cambridge, Mass. A general circulation model of stratospheric ozone. IAMAP/IAPSO Conference, Melbourne, Australia.. Pro Third Conference Climatic Impact Assessment Program. NBSIR 74-430. Study of Minot Constituents in the Stratosphere by Absorption Spectroscopy. Presented at Third CLAP Conference, Cambridge, Mass. Tech. Note 1627, Can. Arm. Res. Def. Estebl. Ozonesonde Observation over North America. Vol. II, Vol. IV. Air Force Cambridge Resecsfch Lrtboratoriea Environment Research Papers. The Physics of Electronio and Atomio Collisions: Invited Papers from the Fifth International Conference, Leningrad (Edited by L. M. BRANS-

COMB). Stretospherio Nitric. Oxide Meesuremente. Presented at Third CIAP Conference, Cambridge, M&es. Soumes, Abundances and Fate of Gaseous Atmospheric Pollutants. Stanford Res. Proj. PR6755, Amer. Petrol. Inst. Washington, D.C.

JAMES G. ANDERSONand T. M. DOXAETJE

884 RUDERMANM. A. and CANERS

J. W.

SCIENTIFICusns OB TEE SPACESHWT~LE

1974

Origin of the Sunspot modulation of Ozone: its Implication for Stratospheric NO Injection. Institute for Defense Analyses, JSS-73-18-3 Report of Summer Study, National Academy of Sciences, Washington D.C.

APPENDIX A ChenriealreQotions

R,,

OH + CH, -(- H,O + CHJ

HO, Reactions

%

0 +CH,-+OH+CH,

(Rettetion rates with refsrences can be found in LIU and DONAHUE (1974a)

%l

O(lD) + HIO -+OH

R4e

O(lD) +H,-+OH H,O+hv+OH+H H,O+hv-tHs+O

H,O + hv -+ products

%

H’+O,+M+HOP+M

R2

H+Og-+OHfO,

Rs

OH+O+O,+H

R48 J lea J IBb

R,

OH+Os-+HOa-l-O8

J BLo

R7

HO,+O-+OH+O0,

RI6

OH+OH+H,OfO

O(lD)

+ OH +Hk*

+ CH, + OH + CHs

NO, Reactions

RI?

OH +H0,-+H:80

RI8

OH +H,-+H,O

-i-O

%a

H+HO,+H,+O,

R,,

H,+O+OH+H

%

R,l

HO, + HO, + H,O C 02

RS

NO,+O+NO+o,

%

OH + H,O,

J NOe

NOa+hv-+NO+O

+H

+ E,O

I- HO,

R ala

H,O,

+ 0 + &O

R Qb

H,O,

+ 0 ---f HOa + OH

+ 0,

Reaction rates with references can be found in MCCONNELLand MCELROY (1973) NO+O*‘NO~+o,

Rx0

HNOI, + OH -+ H,O + NO3

Rl%

NO,+OH+M-+HNO,+M