Adv. SpaceRes.Vol. 13,No. 1, pp. (1)321—(1)324.1993 0273.1177/93 $15.00Printedin GreatBritain. All rightsreserved. Copyright© 1992COSPAR

ON THE RELATIONSHIPS BETWEENVERTICAL OZONE DISTRIBUTION ANDMIDDLE ATMOSPHERE DYNAMICS DURINGSTRATOSPHERIC WARMING AT SOLARMINIMUM

Y. K. Tassev,*H. V. Spassov**andP. I. Vellinov*

* Solar—TerrestrialResearchLaboratory, BulgarianAcademyof Sciences,

Acad.G. Bonchevstr., B]. 3, Sofia1113, Bulgaria** Geophysicalinstitute,BulgarianAcademyofSciences,Acad.G.Bonchevstr., B]. 3, Sofia1113,Bulgaria

ABSTRACT

On the basis of a statistical analysis synonymous relationships between ozone concentrationand wind and temperature — the main atmospheric parameters characterizing warming, are estab—lished.Thè investigations were carried out over Southeastern Europe during the solar minimum.Use was made of the most important levels in the maximum of the ozonosphere, reflecting thephotochemistry and accumulation of this constituent in the atmosphere.

INTRODUCTIONThe stratospheric warmings at mid—latitudes are complex processes. The evolution of the stra-tosphere at mid—latitudes during a sudden stratospheric warming results from complex interre-lationships between the dynamical, radiative, and photochemical processes in the stratosphere,mesosphere, and thermosphere. The scale of global variations strongly depends on the distn~bu—tion of the sources of radiative heating and the movements themselves influence the absorbtionand emission of energy. This leads to the change of temperature and pressure/il. During stra-tospheric warmings, as is well known, there are changes in the circulation of the zonal windcomponent. At the same time there are corresponding temperature variations. These warmingswhich occur at a height of 45—50 km should render some influence on the minor constituents ofthe atmosphere. The present work treats the relationship between the parameters of stratosphe—nc warming: wind and temperature and the partial pressure of ozone’03’ at the height of itsphotochemical formation 23—28 km and at the height of its maximum concentration, 19—23 km.Similar investigations have been made in /2/ for the arctic and subarctic latitudes but forthe total ozone content (TOC). It is established that TOC variation and final warmings areconnected. Subsequently, in /3,4/ temperature variations in the stratosphere were linked tothe TOC variations over the Mediterranean.

DATA USED A~ID METHODOF ANALYSISFor the present investigation we ha~selected three typical winter months (December, Januaryand February) in a period with low solar activity. These were the years 1983—84. 1984—85,1987—88, when there were stratospheric warmings too. The temperature and wind data used (theirvertical profiles) were from rocket soundings from the site in Ahtopol(42 N; 28 E), Bulgaria(Southeastern Europe). These soundings were made every week and as an exception two days con—sequtively. The temperature values were measured at every two kilometers from 24 to 70 km,and similarly for the windbut only up to 60 km. The 03 data were taken from the Canadian cata-logue ‘Ozone Data for the World’. The TOC values from Bucarest station were also used.Bucarest(44 N; 26 E) is 280 km from Ahtopol on a direct line; bearing that in mind , the scale of thestratospheric warnings , the distance between the two stations was considered acceptable.TheTOC data were taken for the same dates for which the temperature and wind vertical profileswere measured. The supplementary calculations were: from the temperature profile of the strato-pause the values at heights 44, 46, 48 and 50 km were taken and were separately averaged forall days that were involved. The resulting averaged value was used which was smoothed to ob-tain the maximum of the stratospheric warming at these heights. The vertical distribution ofthe TOC concentration was calculated according to methods indicated in /5/. The O3(h) concen-tration profile was computed for nine layers. From the profiles thus calculated two layerswere taken with their relative concentration values: at 19.2 — 23.7 km and at 23.7 —28.2 km,conditionally called 19—23 and 23—28. After that all data series were smoothed by three—daysliding values.

ANALYSISThe final quantitative evaluations of the dependence between the parameters of the stratosphe-ric warming and the 03 concentration in the indicated levels of its maximum are given inTables 1, 2 and 3. Correlation coefficients have been determined between the ozone concentra-tion in two layers (19-23 and 23—28 km) and temperature in the layer 44—50 km. In additionthe calculations were repeated using temperature at 70 km; the latter two correlations werecarried out solely for comparison purposes as there was no physical reason for a connection

(1)32 1

(1)322 Y. K. Tassevet al.

between ozone in the lower stratosphere and temperature at 70 km. We have also calculated thecorrelations giving the non—linear connections between the two series for which the linearcorrelation coefficients are calculated . The criterion for linearity 1 is also given whichaccepts values larger than 2 in the case of nonlinear connection. Together with the criteriafor reliability, all calculated values are given in Table 1.

Table 2. involves the same correlations but the series of data have been smoothed by a three-day creeping average. Table 3. shows the coefficients of linear correlation, the correlationrelationships and the evaluation for linearity between the 03 concentration at 19—23 km leveland the wind zonal component at 48 km, i.e., where the height region of the temperature maxi-mum is usually to be found. Similar results are obtained for the 23—28 layer. The values inTable 4. , which have the suffix ‘t’, are the data for three days smoothed by a creeping ave-rage.From a review of Table 1. it is seen that the correlation coefficients ri and r3 are low andthe criteria for reliability is unsatisfactory. At the same time, the c~i~relatT6n ratios Yc’yand Yx/y are high — 0.89 and 0.90 — and they are reliable. This is valid both for the connec-tion of ozone from 19-23 and 23—28 km levels with the temperature at 44—50 km, and for thecorrelations with the temperature at 70 km. The assessment for linearity in both cases, i.e.the correlation of ozone concentration at 19-23 km with the temperature at 44—50 km, and ozo-ne concentration at 23—28 km with the temperature at 44—50 km, firmly shows a nonlinear de—dependence. The correlation of 03 concentration at the two levels with the temperature at 70km, is quite different. On the one hand, there are comparatively low coefficients of linearcorrelation (but higher than the 03 concentration with the 44-50 km temperatures). On theother hand, the evaluation of linearity shows that the connection must be linear. The evidentcontradiction, in our opinion, shows that there is no correlation. This conclusion is validfor both periods - 1983-84 and 1984-85 - but it is not the same for the 1987—88 period. Butas it is seen from Table 1, neither the coefficient of linear correlation, nor the correla-tions are reliable. This is so because of the small series of data and that is why it is dif-ficult to use them for the purposes of generalizations.

These conclusions can be supported by Table 2., where the evaluations for linearity exceed 2at 19—44 and L=2.70, while for 19—70 and 28—70 they are lower. In the 1984—85 period this ismost obvious where for L 2 while r2t=O.1O and L 2 while r4t=0.11. But there is an obviousdiscrepancy when the dependence is linear and at the same time the linear correlation coef-ficient is low. Thus, so far, the basic conclusion is that the ozone concentration in both19—23 and 23—28 km layers has a nonlinear connection with the temperature at the height ofthe stratospheric warning 44—45 km.The results from the analysis of the ozone behaviour at height 19—23 and 23—28 km and the zo—nal wind component are given in Table 3. By ‘t’ we denote the assessed values after smootiTingby creeping average for three days. In both main periods, (for the estimations of the un-smoothed data as well as the smoothed data), the coefficient of linear correlation is highbut negative. Correspondingly, the reliability criteria confirm the reliability of these co-efficients. These conclusions are also supported by Figs. 1. and 2., where the smoothed va-lues of the wind and ozone at the two levels in the course of time develop in antiphase. Thesame but more faintly expressed is observed in the 1984-85 period.

CONCLUSIONSFirst we shall start with the interpretation of the results obtained concerning the ozone—windbehaviour since the result here is more synonymous. It is well known that during the strato-spheric warnings some disturbance of the ozone flux is observed which is characteristic ofthe winter stratospheric circulation. At more southern latitudes a change of the westerliesby an easterly transfer in the stratosphere is realized /6/. Justaposing it with our resultsit implies that when the zonal component is in the east-west direction (E—W), there is strath—spheric warming and then the ozone concentration at the two levels decreases. But this chan-ge in the large—scale circulation is accompanied by relatively large motions downwards, and,hence the regions above are affected by the abrupt warnings /3/. It is exactly these motionsdownwards which create decreased partial pressure of the ozone at the heights under investiga—ti on.As far as the nonlinear connection is concerned which is established by us—between the tempe-rature at the height of the stratospheric warming and the ozone (03) concentration in the re-gion of its photochemical formation and where it accumulates — it can be suggested : sincethe system of the photochemical reactions at a height larger than 25 km also depends on thetemperature /7/, it is not excluded that (03) is influenced by the dissipation of the gravitywaves. Thus after the dissipation in the stratosphere a part of them, varying in wavelength,heat the region of photochemical ozone formation. Of course, the problem is not clarified andthis is only a hypothesis which is to be tested. To this end, it is necessary to study thewhole ozone profile.

The problem of such an investigation of the 03(h) behaviour and the stratospheric warningsduring high solar activity is open. Different single investigations at proton flares /9, 10/show that the solar activity is a decisive factor which changes the state of the middle atmo-sphere and the ionospheric D and F regions.

Ozone and MiddleAtmosphereDynamics (1)323

REFERENCES

1. A.D.Danilov, E.S.Kazimirovski, G.V.Vergasova, G.J.Hachikin, Meteorological Effects inIonosphere, Gidrometeoizdat, Leningrad, 1987,(in Russian).

2. W.L.Godson, Ozone Changes and the Middle Stratosphere over Arctic and Subarctic Areasin Winter and Spring, Quart J. Roy Met. Soc., 86, 1960.

3. R.D.Bojkov, Ozone Changes and Sudden Stratospheric Warnings over the Mediterranean Areasduring the Cold Half—Year, drology and Meteorology, 5, 8, 1964,(in Bulgarian).

4. R.D.Bojkov, Total Ozone Variations and Their Connection with the Changes in Temperaturein the Stratosphere, Ge~g~tismand Aeronomy, 1, 100, 1964, (in Russian).

5. R.D.Bojkov, Calculations of Vertical Ozone Distribution in the Atmosphere According toData about Its Total Content, Meteorology and Hydrology, 1, 10, 1969, (in Bulgarian).

6. R.D.Bojkov, Rare and Unusual Stratospheric Warnings over Sofia in Winter, ~~plogy andMeteorology, 3, 21, 1963, (in Bulgarian).

7. S.P.Perov, A.Kh.Khrgian, The Modern Problems of Atmospheric Ozone, Leningrad Gidrometeo-ET1 w424 578 m518 578 lSBTizdat, 1980, (in Russian).

8. P.I.Vellinov, G.Nestorov, Ch.Spasov,, Ts.Dachev, Y.Tasev, Adv. Space Research, 4, 4, 163,1984.

9. C.H.Jackman, A.Douglass, R., Handbook for MAP, 29, 129, 1989.

T A B L E 1 CorrelatIon Coefficients and Correlation Relationships Obtained fromUnsmoothed Data for the 83/84, 84/85, 87/88 Periods

JCo.ffic. lError of Criteria Criteria Corre _Relibi— Corre —IRelibi— IEstin,o—IPeriod of lineor the linear for reli— for reli— lotion laity of lotion laity of tion

correla— coefficient obility obility relo— correl. rein— Icorrel. forlof correl. :l~0b00l table tion Irelotion tion relation Iljneor

— •r tr t va/v ,j~tYx/y Yy/a t Yy(n t.

163184112.1.2In—is

19—44 rlt.0.08 0.25 0.34 2.12 0.89 3.56 0.89 3.56 2.79

119—70 r2t.0.38 0.23 1.63 —‘— 0.89 3.87 0.67 2.90 1.74

28—44 r3t.0.19 I 0.25 0.79 —— 0.90 3.58 0.89 3.56 2.79

28—70 lr4t—0.15 0.26I F

0.56 —~— 0.90 3.60

—F————————0.67 I 2.68

—I2.07

—

84/851112.1.21

II

II I

n.14 I I I19—44 nt. 0.06 0.27 0.22 2.15 0.16 2.61 0,83 I 5.09 I 2.1119—70 Ir2t— 0.10 0.27 0.36 —~— 0.76 2.81 0.10 0.35 I 0.00

128—44 Jr3t.—0.14 0.26 —0.54 —~— 0.84 3.23 0.83 3.07 2.4328—70 rkt— 0.07 0.27 0.24 —~— 0.64 3.11 I 0.10 0.57 0.21

187188112,1,21n.8 I

119—44 Irlt.—0.16I 0.35 —0.45 2.31 0.42 1.19 0.61 I 1.73 0.9119—70 Ir2t-—0.201 0,35 —05728—44 Ir3t-—0.161 0,35 —0.45

——

——

0.420.22

1.200.63

0.840.61

2.40I 1.74

0.871.07

28—70 r4t.—0.20 0.35 —0.59 —~— 0.84 0.84 I 2.40 I 1.07

150.00 ~D.L 200.00

1 150.00

140.00

100.00

130.00 ‘ 250.00

3

120.00 0.00

—50.00

110.00 —100.00 ~ 2

100.00—150.00

Duy�90.00 ~,,,i’,i’’’ ~,,, —200.00

0.00 5.00 10,00 15.00 20.00 0.00 5.00 10.00 15.00 20.00Fig. 1. Ozone at 19—23 km (curving line 1) and at 23—28 km Fl

9. 2. Temperature at 44—50 km çcurving line 1) and 0t 70 km(line 2) with the data smoothed by 3—day sliding values for (line 2), zonol component of the wind (line 3); their smoothedthe 1983/84 period, values for the 1983/84 period.

tion

(1)324 Y. K. Tassev etal.

T A B L E 2 Correlation Coefficients and Correlation Relationships;the Series of Data Have Been Smoothed by a Three-day Creeping Average

Coeffic. Error of Criteria Criteria Come —Rel.ibi— Corre —Relibi— Eetima—‘Pariodlof linear the linear Ifor reli—Ifor neli—Ilation Ilitv of lotion lity of Ition

cornea— coefficientlability lability rein— Icorrel. rela— correl. fortion of carrel. colcal. table tion relation Ition relation liinear i

r 1 Sr

162/8412.1,21 I

In.16 I II19—44 nlt-0.24 I 0.26 I119—70 Ir2t—0.12 0.27126—44 lr3t.0.38 0.25~28—70~r4t—0.15 .20

I~/a~I I112.1, 21In.1’~ I119—44 Inlt.0.30 0.28I19—70 Ir2t.0.10 0.29128—44 Ir3t.0,07 0.29128—70 r4t-0.1i I 0.29

-1-187 /88112.1.2In—SI119—44 lnlt-0.35 0.38

19—70 r2t—0.05 0.41128—44 n3t-0.40 0.3828—70 r4t——0.08 0.41

tr

II

0,94 I0.121.53

0.50

1.07

0.330.230.24

II 0.910.121.05—0.21

t

2,15—~—

——

——

2.18——

——

——

II 2.45I ——

I ——

—~—

~,Yx/y,1

I I0.990.990.940.96

0.950.950.82

I 0.97

~—

II 0.42I 0.42I 0.56

0.26

t Vo/y Vy/x

I3.85 0.943.70 0.863.76 0.963.69 0.66

I

3.40 0.823.28 0.612.83 0.973.34 0.69

—

1.11 0.561.02 0.851.40 0.260.63 jO.85

t Yy/x

3.633.193.863.29

2.912.12 I3.342.38

1.472.070.682.07

1

2.702.532.702.51

2.12

1.612.271.89

—

0.490.68—

0.52

T A B L E 3 Unear Correlation Coefficients, Correlation Relationships, and Evaluationfor Linearity between 03 at 19-23 km and the Wind Zonal Component at 48 km

I I I I I I I I I

I Coeffic. tError of Icritenio ICnitenia ICorre —IRelibi— Icorre —Ioelibi— lEetimo—IPeriodlof linearithe linear for reli—Ifon reli—j lotion Ility of Ilotion Ility of Ition

icorreio— coefficient ability lability Irmia— Icorrel. Irelo— carrel. Ifortion of comrel. coical. Itable ltion ‘relation Ition Irelation ll.inear~.—.1. —i ~———-———---—

,_~_, Sr tr t Vx/y t YxJy vy./xI tYy/n i

183/841112.1,21In~18 I

II I

119—48 In -—0.451 0.2228—48 1r2 ——0.481 0.22

I- I I

—2.00—2.17

2.12——

0.890.90

4.05 0.74 I 3.354.09 0.74 3.36

~{—}—

0.431.77

In—is I I119—48tInlt——0.46 0.24128—48tIr2t——0.52 0.23

—1.96—2.31

2.15—~—

0.990.89

1—

0.760.84

F—

4.133,87

0.900.90

3.773.19

2.302.14

—.I—184/851 I I I I112.1,2 IIn—is I I119—48 In .—0.23I 0.26 1—0.80 2.15128—48 1r2 ——0.42 0.24 1—1.73 I ——

I I F

2.923.50

0.770.77

2.953.21

2.151.92

ln.14 I I I I119—48t1n3t-—0.46I 0.26 1—1.78 I 2.18128—48t1r4t.0.11 I 0.25 L2~14 ——

I I +

0.95 3.650.97 I 3,88

—1

0.84

I 0.84—

3.243.38

1.951.81

187/eat I112.1.21In—b I18—48 In1 —0,44 0.32

128—48 1r2 .0.41 I 0.32I 4

1.401.28

2.31——

I

0.420.22

I

1.310.69

IIIj 0.90

I 0.96I

3.00 —

3.00 —

I—10—81 I119—4StIrit.0.32 0.39128—48t1r2t.0.29 I 0.39I I.

0.830.73

2.45——

0.420.26

—

I I1.08 0.58

I 0.67 0.58

1.491.49

-i

0.51—