The Mars-2 and Mars-3 orbital spacecraft: Results of the investigation of the Martian surface and atmosphere

N4SA TECHNICAL TRAHIiLatx'Jn

NASA TT F-li;,3l4

^S KS;!.^"^ ^'-^^-^ 0R6ITAL SPACECRAFT: RESULTS OF
TnE INVESTIGATION OP THE MARTIAN SURFACE AND ATMOSPHEPJ

V. I. Horoz

Trans lat ion of Orbital 'nyve Apparat v Mara-? 1 Mars -3 •
Rezultaty Issledovanl y poverkhnosti 1 at^^ife rv MarsA.
Author's manuscript, Moscow, l ^j, 1^ pp • " — ' ^

20 p HC $3.00

Onclas
G3/30 628J12

NATIONAL AERONACTICS AND SPACE AK4INISTRaTI0N
WASHINGTON, D.C. 20546 FEBRUARY 1973

- ..%

STANDARD TITLE PAGE

I. ««p«fl Mo.

NASA TT F-i4,3U

-.. . «,

Hm.

! 4. T.t!» saj S«i>t.iU

jTHE MAP.S-2 AND MARS-3 OHBITAL SPACECRAFT^
I KESUIiTS OF THE INVESTIGATION OF THE KAR-
jTIAN SURFACE AND ATMOSPHERE

3. it»c>pi*nt*t Catalofl No.

5 Km^vrt Oat*

February 197.3

6. Pmrinrmif*^ Orgonttotior Code

7. ^«|fnoW -.}

V. I. Moroz

' 0. P««Fetftif«^ Org^^itotion R«por' No.

i!2. 1»oH, Unit No

9. Pcvfoming Orgonttation Noeo ond Ad^roti

Leo Kanner Associates
Redwood City, CA 9-a>53

-^11. CoArr«ct or Of ont No.

i NASW-2481

13. Tyv* of Robert ^t%4 Ponod Cav^rsd }

12. Sp3Rsoring Agency Noa* and Aierm%%

National Aeronautics and Space Admini-
st-'ation, Washington, D.C. 2054b

- Translation

14. Sponsorins Ajoncy Codo

IS. Svpploncontory No9«l

I Translation of Orbital 'nyye Apparaty Mars~2 i Mars -3: Resul-
! ta~y issledovaniy poverkhnosti i atmosfery Marsa , Author's
; ina:~iuscript, Mcscoiv, 1973 > 19 PP

)6. £.i»tiact

- Six differents were conducted on the Mars -2 and Mars -3
orbital spacecraft studying the Martian surface and lover
atmosphere duririg and after a dust storm. Sui'face tem-
peratiire, sell temperature, dielectric constant, relative
I altitudes at the planetary surface, surface brightness,
I H^O content, and the density of the lower atmospheric

I neutral gas and the electronic density of the ionosphere
were determined. Instruments used included an infrared
radiometer, radiotelescope, CO^ and H^O pLotometers, and

a photometer in the 3700-69^ A r^ge.

I 1?. K*y Words (SMWtM by Author^t))

1

19. Socunty CloMif. (of ltli» roperl)

Unclassified

IS. Oittribulion Stolononl

Unclassified - Unlimited

30. Socurity Cla*«i(. (el thi* pogo)

Uiiclassified

31. No. of P.j«os

20

32. Price'

^\

NASA-HQ

THE MARS-2 AND :.IAHS-3 ORBITAL SPACECRAFT: RESULTS OP THE /la*
IWBSTIGATION OF THE MARTIAN SURFACE AND ATMOSPHERE

7. I. Moroz
Introduction

Six different experiments to study the physical parameters .
of the surface and lov;er atmospliere of the planet were placed on
board the Mars -2 and Mars -3 orbital spacecraft:

1) variation in surface temperature based on ^adiatlon in
the 8-40 um rar^e 11^2.,^/,

2) variation in -soil temperature at a depth of several tens
of centimeters and- variation in the dielectric constant based on
radiofrequency radiation in the 3-^ cm wavelength £^^J»

3) determination of relative altitudes at the planetary sur-
face based on the intensity of the COp bands at about 2 urn

4) photoelectric measurements of surface brightness in six
narrow intervals from 3700 'to 13,S00 A /1, 2,6,;^,

5) measurement of HpO content in the atmosphere based. on the
intensity of the I.3S fim absorption band /T,2,77, and

6) radio probing of toe atmosphere to determine the density
of the neutral gas in the lower atmosphere and the electronic den-
sity of the ionosphere /~3_J7.

The infrared radiometer and the photoelectric photometers for
the COo arid iL-.O bands and for selected regions of the continuous
spectrum were described briefly earlier in the works" /T,2, 5,6,7^9/;
Table 1 lists the main characteristics of all the Instruments
(field of view and measurement precision).. The optical axes
of all the instruments wei'e parallel and the surface and atmo-
spheric parameters were measured in the same planetary regions,

* Nvmibers in the margin indicate pagination in the foreign
zcxt .

£f -

«f

dielectric constant, altitude, pressure, and HpO content in the
atmosphere i-fere obtained for the same regions.

The instruments -.vere hard-mounted on the body of the AIS
Automatic interplanetary station/ and during the measurements
they v:ere oriented in a constant direction usually vfith the
solar-stellar orientation system of the AIS. On approaching the
pericenter of the orbit., the instruments v.ere switched on for
several, minutes prior to transiting the limb, v:ith a special
optical serisor. The optical axes transited the planet usually
along a line close to a great circle and the transit from licb
to iirab took about 30 minutes. Belov; ;i-e v. ill refer to the trace
of the optical axis on the planetary surface as the track of the
measurements. Prom a preliminary estimate, the precision vrith
v;hich the measurement track vras determined v.as 1-2 based on

■ J"

I areographic coordinates. . {,

i ' - _ • ^

- In the experiments /T-5/ all' the results are from Mars -3. si

- - ■ 1 ^
1 Its period of revolution was about 12 days. Fig. 1 shows seven

I measurement tracks made with this spacecraft.

The distance at the pericenter to the Hartian surface varied
somewhat as the orbit v;as evolved and v:as roughly in the range

I IOOG-I5OO km during this period. The first three transits,

I'

I . 15 December 1971, 27 December 1971, and 9 January 1972, took place

I during a' dust storm and its abatement, and the remaining transits

I -- after the end of the dust storm, in December, January, and

I February the measurement tracks corresponding to successive dates

i o

V ' of transiting the periares v/ere shifted by about 90 in longitude

$ r

l v;ith respect to each other. As a result, sizable sections of

I

I the 3 February 1972, I6 February 1972, and 28 February 1972 tracks

I past close to the 15 December 1971, 27 December 1971, and 9 Jan-

\ uary 1972 tracks, and we have measurements for the same Martian

i regions 'obtained during the storm (more exactly, during its last

' stage) and after the storm. The 12 March 1972 track could not.

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for* a number of reasons, be tied into the surface with sufficient
reliability and its position as shown in Pig. 1 must be considereo.
as approximate.

> Overall, the volume of information obtained v.ith Mars -3 was

somewhat ■ less than with Mariner-9. However, experiments were Z2.
.conducted on Mar3-3 which v.-ei'e generally not included on Marlner-9
(photoelectric photometry in the near infrared and visible opec-
;. tral regions and radioastronomical measurements) , while as for
'\ the experiments similar to those conducted on K?-'iner-9 (IR-
'■ radiometry, optical altijnetry, and H^O content measurement), ;

the Mars -3 results are of interest not only as supplementary i

-' material since — firstly -- they afford a:i integrated consider-
ation together with phovoraetric and radioastronomical data, and
." -- secondly — they were taken with widely different methods.

j In particular, the measurement of the H^O content and COp- I

Si altimetry in our experiments were made for bands lying in the j

f' near infrared region, and the meas'irement results are practically I

§; independent of the vertical temperature distribution. Bands in -|
is, '

the far infrared spectral region "were used on Mariner to get the

same data, and these bands depend so strongly on the vertical
temperature profile that they can be observed both m emission,
as well as in absorption ^O/. Though the analysis of the spec-
tra obtained with the IRIS /Tnfrared interferom.eter-spectromgtery^
simultaneously yields j.lso the vertical temperature profile, the.
problem is greatly complicated and, probably, does not always
admit of, a unique solution. The topographic material obtained
^'' with Mariner-9 using ultraviolet photometry /Tl/ is very valua)3le

due to the global^ty of the coverage, but requires a cautious . •
approach since it is strongly subject to the effect of inhomogerx-
eities in the atmospheric dust ' content .

m

Below we propose to briefly review already published data I
and present new results.' They apply to the first sixMars-3 .1

sessions. . ■ ' I

i-

h

We are indebted to N. N. Krupenlo and I. B. Drozdovskaya for
giving liS the resulta of the redloastronomlcai experimenua ucxwic
publication.

We are also indebted to D. Shneiderman (nA3A) for the Mar-
iner photographs of the Martian surface in the regions extending
along the Mars-3 measurement ti'acks. In several cases they /4
assisted in the interpretation of measurements. Their compar-
ison with photometric curves confirmed that the tracks were deter-
mined with the above -indicated accuracy of 1-2 , and in the follow-
ing the track position can be calculated with the aid of the Mar-
iner photographs.

2. Direct Results of Meas irements

Figs. 2-7 give the results of measurement's along six tracks
pertaining mainly to the surface. The brightness infrared tem-
. perature T„, soil temperature T_^ (at a depth of several deci-
meters) measured on the basis of radio frequency radiation at a
v:avelength of 3.^ £ni, dielectVic constant e, brightness in the
continuous spectrum (photometric profile) In the near infrared
region 3 (1.4 fim), and altitude Z relative to the 6 mbar level
are presented. Here are also gl en, for comparison .with the
results of the measurements,' the values of ^, -.- the ^osine of

the solar zenith distance — and T~ — the theoretical mean- ,

s , ■

diiirnal surface temperature. -

Fig. 8 presents separately the altitudes for 27 December
1971. They are separated because over much of the track they
clear refer not to the surface, but to the cloud cover

Pigs. 9-i4 'concentrate the results pertaining mainly to

the atmosphere: pressiire P, H^O content profile* and brightness .
■,..■,■,■•.■,•■ • <= o

(photometric profile), in the near ultraviolet region of 37.00 A.
Here also are given the brightness at the wavelength of 4940 A,
detera:Jjied.;by- scatter;ing'bQth by the ^sur face and the atmosphere,
ah(i the brightness" at. the vravelength of 6940 A, determined by
scattering mainly by .the surface ,( just as for lAiim). The

.■3

latter remark is valid only for measurements taken after the end
cf the duct storm. rhiT.incp t-.hp i^i December 1971 and the 27 Decem-
ber 1971 tracks the brightness In both the red and near infrared-
regions was due significantly to reflection from dust clouds'.

The, method of processing infrared temperatures is given in
the papers /l~3/-' We recall that a wide-band filter was used in /2
our radiometer and in the region of the fundamental CO^-- absorp-
tion band ( X =15 Mm) the radiation was determined by the atmo-
sphere, which, can be colder or wanner than the surface — depen-
ding on specific conditions. ,T6 take into account the atmospheric
effect in the first approximation, in the neighborhood of the
15 MiTi band we increased • the measured fluxes by 5 percent (which
gives a correction of • about 1 percent in the temperatiire) . Ac-
tually, the magnitude and sign of this correction.^ depend on the
•local time, atmosphere model, and the zenith angle of the craft. - ■ L
Below we will suggest determining the co v-'ection for absorption |
more exactly. . • |

. . The brightness infrared temperature T^ is -"-ery close to. the

kinetic temperature of the surface layer T_. And. actually, by

• neglecting the difference betv;eenT„ and the' effective tempera- • .

ture T^, we have ;*;■•'.. .'■ '..,,•

<-. . ■ ' ' •':<'■»■■••

where B, is the coefficient of radiation in the. infrared <range .

Laboratory measurements ^2/ for earth minerals yield B, =* 0.95",

so that if we assvune .the same value for Mars, the difference'

.between, T^ and T and T fwill be of the order of . i. percent., The

ratio' TT^/Tr .depends weakly on B, , as the root of the foiirth power.
ij s ' . ■ ■ ■ X-

The sltiiation'i^ even.v/eaker in the radiofrequency range, where
lihe following relationship holds:

. '"' ' :' ■• ■ '^b'. = Vss * . ■ (2).

Here the error due to indeterminacy in the Irnowledge of Bo (the
. coefficient of radiation in the radiofrequency range) is; somewhat.
6 ■ ■ ■ ■

! '

i
.1 L

, CV

greater./ However, the radiofrequency experiment was constructed
• In. such a way (measui-ercent in two polarizations) that it permitted
determining B2 and Tg separately. In processing the observations,
it was assumed that the Martian surface can be represented, as a •
smooth sphere.. The coefficient of radiation for the sum. of the
two polarizations in this case is equal — by Fresnel's law —
to ,_■■,, ^ ■" . . ' ■ ' ;

/

f:

I

• s

= 1,

tan (Z' —2) '..'.^ ■ sin':(Z-' - Z)

(3)

tan (Z;'. +' Z) " sin'^CZ' + Z)

where Z is the zenith angle of the craft,, and Z* is determined,
from the relationship ' •' , ■

■ ■ - ■ • ; sin'z

•ZL

sin Z'

= ^1

'<T.

w

Pigs. 2-7 give the values of T,„ and t separately. The

So

errors in the, determination are evidently due to the disparity
of the- actual surface from the adopted hypothesis of a smooth
sphere. The too large and too small values lead -to overstating
and understating T„„, respectively. V/e can discax"d these out -of -

y SS

line points if we compared T;,^ with the mean-diurnai temperature

of the surface T~. It must be anticipated that these values will

s ■

be close to each other for Martian' soil. In Figs* 2-7 we plotted
the tT values calculated by the formula - ' •

= (-

"0

1 ^ A

cos Z)

y^ '^ ' ' :

(5)

(jr 1. .• •■ .

where cos Z is the mean-diurnal cosine of the zenith angle of the
Fun, A is the integral albedo, Eq is the splar constant/ and r
is the distance to the sun in astrpnomical units. We' assumed'

1 ~ A
the' T,

= 1.

On the average, the T„_ values lie roughly 20. below

curve, which can be attributed to calibration inaccuracy.

\.

7

; '

1 4

afe^

I I

.■:• ',■ . ' J L

I

'f

The ' method of (te'ter'^inlng pressures and relative altitudes
-Is given in 'the' works /li.^t^ and the methou of water content

' detehnlnatlon is found in /~7_7. ' "-.

,,'■'.'.• .' - •■ ' • • ■

'Brightness B raeasureihents were talcen only in relative terms,

'■but here it is essential that the brightness scale is the sair,'^

for all sessior^s. Absolute brightness units plotted on the or-

dihate axes for I.38 Mm were obtained on the assumption that-

for 15 February 1972 and 28 February 1972 ^sessions the brightness

in the 'light regions is subject to Lambert's law, and the bright- •

ness coefficient (visible albedo) for the .light regions is 0.4l. , ,

The fact that gn Mars during the period when the measure-
ments were, begun, the dirrt storm still continued has both nega-
tive and positive aspects. A negative aspect is bbvious: the
• presence of dus\- clouds interferred with the photographing of
the, surface and reduced the posaibilities of several optical ■ /7
experiments (HpO and CO^-photometers) during several of the first
.sessions. Even so, the dust storm brought a benefit, since never
before' were there as great oi^port unities for studying the
natxu'e of .this' tremendous and puzzling phenomenon.

3. When Did the " Storm Begin and How Much; Did It Affept the
Results of Measurements " . . . ■

• Relevant photofelevision images on Mariner were' obtained sys-
tematically since late in December, hov;ever as fai'' as we? can Judge
from the photographs we have at. hr'nd .the trahsparency of the Mar-
tian atmosphere/continufed to, increase during this' period. , ,

. How transp'arency varied with time can be- traced from: our ,
photometric profiles. Table' 2 gives' the- mare -highland contrasts,
for 2.38 Mm in different sessions.- Here are also giyen the ' '
cosines of the zenith angles of the sun and the craft (m'j and' ^2)-
and the phase ang?.es a . 'The contrasts represent the ratip '

B« - B„
c m

whei^e B_, is the mare' brightness (solid curve), and B^ is

m

, 4

. -A'

I

the brightness of the highlands (dashed curve), yielding the

8

Lambert Ian interpolation of the brightness level corresponding
to' the highlands. Table 2 also giye's, the values of the highlands

brightness R corresponding to the dasheri' e for -each track, /o

° , max , . ' ' —

Obviouslyj in general they are systematic -y r^ red^on 1^ Decem-
ber R was, 15 percent greater than in tnt.' tv.o lb.^t sessions in
max . ^ ^ c .

February. ' .■ ■ .

Si.

I

r.

w.

. .'

' *v '

.TABLE

2.

'

'

iSess^on

■ \

r\ r\r- Iff r^

J' . » -^

-Tr^

' ^2

4

'a

E ■
max

r\ iirr

27 Dec 71' 0'. 32 lap'igla -26' 304 0.53^.0:992 53 0.45'
9 Ja: 72 0.5I -M. Erythraeum ■ -23 29 ,0„6o6 0.999 5^ 0.44
3'Feb 72, 0.39 'M. Cimmerlum -30 215 ■O.826 'O.855, 56 0.45

16 Feb 72 0.56 lapigia ■ -25 299 ' O.872 ' O.816 57, .0.41

28 Feb 72 0.55 M. Erythx-aeum -25 -' 30 O.671 0.915 59' 0.4l . •

■ ' ' ' • .

On 9 January 1972 the mare-highland contrast values were
now close tc the values -reached in the February sessions, though
■the difference was still present. , , ^'

. Atmospheric transparency clear]-<7- oepends on latitude. At

latitudes south -of 50, in the l-~> Decf; nDer.arid 27 December sec^sions

the profile's (l. 38 mhi)' contains a lar^e nuqber of fine details,.

while, closer to tne' equator there, are no details and the marla

have the appearance, of smooth *ninima. Oh 15 December, the 'red

'0 • . ■ ' , ■ '

profile (6940 A) showed Prometei Sinus/ but Mare Cimmerium was

altogether absent from it . , , , , . , ,

.The 'general impression^ is that on I5 December and 27 December
1971 the dust content of the atmosphere v;as so high that the, re-
sults of measuring pressure, altitude, .and *H^ conterit for lati- ,
tudes north of —40 were greatly impaired , by the dust .sto'rm.
There is some uncertainty also in similar results for 9. January
1972. S6 the/curves of pressures, altitudes, . and HgO content
for , le first sessions are- plotted with dashed lines, and for

■4

i

v;

! ■

f :

27 December 1972 these curves are not given at all, since in" this .

Session the equivalent COp bandwidths were especially small." In '

another figure (Pig. 8) at^e given the- 'alt itudes^'^foi^thlsr' session;':-

in the i'ollowlng they will be used in determining the .altitude'

of the 'upper cloud ceiline./ .^ ' - y^ ■ ■ -''', /^

. ^ ^ y ' •

. ■ . • ^ •** .-"

The altitudes determined in the Jij December 1971 and 9 'Jan- -

uary 1972 sessions can probably be used.;;ith cation in the,

role of some qualitative characteristic 'of the relief.

The infrared terrtp"eratur€ found fronyj*adiatfon in th,e\8-r4cr

jura range pertains to the surfa,,oe^even for the December ^s;es,s ions; -

Tv70 arguments canr 'be -cited favoring this cpnclusion: -'', ' * , ■■

1) Atmospheric transparency clear*ly increases with v/avelength ■^'
in the transition from 0.7 to 1.4 ^.m.. ' If this is attributed to - . ' ^'

y

y

yi

-''^^

small particle sfzes, which is most highly crobable^ then, for /

the radiation at X^8/^jxm the^dust clouds must b I" completely /9_ '•

:' ■■ y y" ' /j _ ^ . . 1

transparent . , , ' ;,_ - , . ■ . ' „ -?

. 2) The d.3Dendence of temperature oh local time correlates 1

quite well - che tiie^i-etical depqjadence calculated without ' '\

allowance he atmospheric radiation. . tchej:'^ is only the dif-

ference that the measured temperature curye,,-lles sonfevrhart below

the theoretical ciorvev accoimted 'for by the absorption of solar

radiation in the clouds /T,2,3,67-x1*hiB me'ans ;^at the opoical

thickness of the dust clouds is small in'^the Yi>.. ^ilty-of \ > 8,;tin. z^-

/

f

^

4. Marxian Surface: Temperature, . Soil Densit.;-, ' and Altitudes, .^^'

T emperature and thermal propert>6's o^ tjie; surf ace layer
— __ /- >' ■

The theoretiical effective,a^urf:_ce temperatures T "Were'cal-

' y''^^ • ■ y' ■ ! < e -1 /p -f^

culate'd for different value.s^'bf the . thermal inertia (k p c) /for. ' ,- |

values of the' -integral albe.do'A/^0,25. (ilgbt leglohs) and' A =^^''/ ' • '- I

'= 0.15 (dark regions). The T^ projfilet* 'f or 16 ' February 'and' 19' . ' _ )C^

February 1972 are satisfactorily .approximat.e.d -by, theoretical ' . " L^

curves with (k pc)"^/^' = O.OO6 cal-cm^T^-sed'^'^/ -'deg"^ ,(Pigs. ,,. ■' ,

-J ' , ' ■ . y' ' ' ' ' ''' ' ' ' ■ '^'

15 and 16). An exception is represented by the lat^Itudps , ■ .■■,

^ .> +40° where the measured tempex-atures, are v^ry much bel^^'; , ' , 'I ,

' ■■,',■-• 'y ■ ■ ' ■ ' dS .'

10 ■ . '■•••• ■•■•■'■• '•^■:, _ ■ -, ; ;,^ ., ■ •

', . I

I y

. I

•,''*' .> it /

^■. . . v..

>-

f '<:--,) , -'v^y/'

, y.

f

.# ,.
•«^,

•'.-■ '^^X

' .i^'i

r'.

>

y

'fj

iv^jR-"*3fc"

the th.eq]?gticial tsipperatures and' are. close to the co?iaensatloii^'^ ,
/"^ temp^eratur^ -'of COm at.. the'-Idxltudeg <^- ^ ^0 i" • - >• -** .^'f '-'.-/' /^ f

.;■ An Increased -tAerci. -»ertia:?t.ohstant (CT. 003) v/as foijarid<'i?)b-''';>^<>' ,
' , >.:i the area of the ccrapact dark regioii Cerebrus,. ^'Obvious ly/tlfere':,''' V- '

/ >^ ■ , • is-. a vreli^defined correlation between T^ and brightness B tl.io ' /' 'fU
.y^'ii.-' " .'."Mm). .. Regions w^h lower 'brightness '(],ow^er reflect iv^tyj b^>,etl' ' •

^ hlgheft' temperatures . v< . .<-r" v ',> ^v • , '^ -', , - -

'•^ <'-. ■ -• ■ '" . 'V- ; V^ -••-'■■ ^ •-■-■ y^ ■ "^K

■ ih' the diist storrh.'peridd C'i5 December^and 27 December' 1971) •*
' ■''' ' ^ '/ '■ . ■ ' ''"',''. i'' ' ■■'' ' -''■ -^' - '■' . '' . , '/ ■

the ^ui?faet;>'t'emperatiire was. bi^ow '"rtbrnittl"; 2?.r^;3',67; this is , ..- -
also Indid^tjed' by -j;iTe Marlnfe^ ,raeasureinehts,-^j7 and terrestriajls^
"Observations by the author". and b'is coworkers^yT4/. ", . • . ■ * ; <

,.- ' y. -^' ■ " ■ ■ ■ • . ■ • . -^ X'' y ■ .. ,' s ' ■ '

Temperature/' diiilectrig constant,' and aoil denrsity' (reSjalts ■ . .

of radjoastronoAlcal experjn entjf^"^ ' ,',..:-

.F'

^-

^

• ' ■^ '. .

^■^,

/ t

f-' f

>

LI temperature at' a depth of^' several- dec JtoeterB cor--- t,
i^factbrily with the' calcUlSitee' njean-d^ .Trn'''l tecipera- -t

,/

>'-' ' Th-- /soil

relates aafi'^factbriiy with the caicuiatee' laean-a^ Trn'^'i renipeT

, ' • ' -•^ '• ■,''''. ' '.• • J^ '' '

tures., As.^to. be expejcted, there -are no sigi^s •o'f, dilirna?!. soil,. ^' /lO

temperature flu<ftuationS'. If sections whoT^e the .temperature ,T, ■ ?,

differs widely from the cal .;ulc>tc . temjserat^re' T^ are dis.iarde'^cS' . '

the me an^ value of the die lectricr cons tant^ ao •. " .' ,

y ■ ■ ■ ^ ' , ' - ' ■ ,.','' ■'■'/-

■ ,,'-'' ^f *^^>^'^±-'l-/- '.■ ■ ,- ' ,' '.-■•; ' '^ '. ■'

which eorresponfis to.the .norniai'^f^ = 0) coefficient of rtc'lation , -

• ' 'me dielectric jxJhstant f^j?'most anhydrous e^i^th- minerals,

as sh'bwn"by'Krptikov-/T57, is related to the suil density 'p oy .' -,

"they're lat'ionsh'ir , . -'■ ' .^ '* .-"'/■ ' ' ;

whence, vr'e/have the following estiiffite for the -lensity. cf Martian' '•''• .--

■ so-ii ' :■ ,^-^ ' " • . /^''-' .--;■' ' ■ : .'

p = 2 g • era

/

By' cw&paj?ing B (1.3&. Mi") and' f "To'r the' track^ '.from S Taiiuary '
, ■.1972' to 28 Pebruar^r 1972, we can see ihat in the darl? i'^gions^'-
there, is .a tendency* t9wsrd art inprease-in f (and thus, density),

.,', •' '■'; '. • . .-^ ' / . ■■- '' '. /-'■ ■ li

^

n--

j Altitizdes

Aitituc i profiles also correlate .ilth brightness — to a t

lesser extent than do infrared tesperat'ores , but the correlation
anconcitioiiail^ does exist. This correiation is not alnays Kell-
defined and no atttfntion >:s.z ^ivea to it in the first publications
_^i2,27- ^y CK=paring altl ude profiles and brightness profiles-
in Pigs. 2-7 Ks can still see that the darker regions are generally
hiriisr than the neighboring iighter regions.

Altitudes relative to the 6 nbar lev^l in oiir trackt were

in the liialts -1.5 to 6 ks. The highest regions are located) in -"

Mare Australe (9 January 197^ track), Syrtis Major (l6 Pebroary .^

.<- 1972 traclc, about ^ kn) , Kereidiaa FretuE (26 Februdxy 1972 track, %

ato'^t 4 ka), ar^ ti»e loves t are in Ixabra (l5 February 1972 track, j

about -i iis) and Chrise (25- February i9?'. track) . The tracks of >l

'i iS February and 25 Febrxzarv 1972, extending far into the .'-orthern ^4

;■ latitudes, show a tendency tovarc a systecatic iowerixjg of altl- ^

# tudes In the northern hen;isjM-:^re. This is also shown by the -^
1^ r^.iio occultation observatior.s of Mariner /y^J . '

£- j. Kartian .^tncs r / ?re; Pressure, a'ater Vapor, iKist Store, and /n

&" Hi^-latitude Clcuio

# ft?essure . •
*' Absolute pressure values leternined fx^ons our observations are

■ s ■ - *

^ not rell:^wie enough for firial conclusions; however, the Impression

Ir is obtained that the value of >_ irbar Is somewhat higher than the

f^ nean value. The cean value is evidently closer to 5-5-5 mbar.

f. Pi^ss-ures measured for all tracks fluctuates within the lluiits

53^ 3.5 to 7 abar.

^ - • '

1. Radio occultation observations of Mars-2 yield pressures of

fe-' —

% 5-10 mbar /~S /; th.^se" results will obviously be refined.

1*^ • "" •

# feter vapor - ' ' '

E Along the tracks of I6 February 1972 and 2S February 1972 the

% water vapor content in the atraosphere reached u^ = 6-8 um of

I. 1-2

f

e.\»

»fe?

precipitated water. Mariner-9 /y±/ and terrestrial observations
conducted simultaneously /!.€/ yield about 10 fim of precipitated
water on the average for Mars. The agreement can be regarded as
satisfactory, considering the possibility of geograjrfilc and time
variations (and also changes in our calibrations) . The rise in
u, in the period from December to Februai^y, found by measurements
on Mars-3, vras independently confinned by terrestrial observa-
tions 1^0/ . Tnere is some correlation between water content in
a vertical column and pressure, as must be the case in the ab-
sence of saturation (the relative huaidlty was of the order of
several percent) everywhe^"^, with the exception of the cold regions ;
in the northern hemisphere. The abrupt drop in humidity at lati-
tudes north of +50 was accOTjpanied by the formation of neaj?-
polar clouds strongly scatterJjig W -radiation (cf. Fig. 13). On |
the average, the water vapor content in the Mao^tian atmosphere j
in the measvirement period was several times less than in the --_

same season as shown by terrestrial observations during the period - ^^

-I

*'■ of the preceding oppocitions.

V' ' • "

^ Dust storm

here Vfe '«iJ.l deal with three problems — altitude of the
clouds, particle sizes, and the effect of the dust storm on the /12
thermal conditions of the surface.

a) Cloud altitude

Very low pressure (down to 2 mbar) and altitude (down to
IO-I5 km) values were rotained for the 27 December 1971- track
(in the zone lyirig north of —30°) after processing of the COg-
photometer observations using the standard methr>d. It is natural
to assume that these pressures smd altitudes refer to some effec-
tive reflecting level in the clouds. Thus, their altitude proves
to be of the order of the altitude cf the homogeneous planetary
atmosphere. Similar results were obtained in the terrestrial
observations of the author and 0. G. Taranova /y[/ » and also by
Parkinson and Hunt en /IS/- '^^^ distribution of temperature with

H

X

13

Our estimate is based on the simple fact that the transpa-
rency of the clouds at the 1.4 }im wavelength is inarkedly higher ;
than at the 0.7 Mm wavelength. This is especially clearly evi- ,
dent from a comparison of the red (0.69^ jxn.) and infrared (I.38
fira) pix>files of I5 December 1971- Since the cloud albedos (and
tiius also the true absorption) at these wavelengths are nearly ;'
identical, the difference in transparency can be attributed only
to the quite small ratio of /adiu" to wavelength. An approximate j
quanti«aclve consideration yields the estimate indicated above,
r =* 1 /i ni.

The optical thickness i" ,

T = /a- dZ ' '.

2 , ;

(where a^ is the coefficient of extinction) must be about 3 *

'i •

i for l.U iivs. and rnore than 6 for 0.7 uni in order to explain the

I 15 December 1971 observations at this radius. • ^

i- - },

W It is very important not to err in the mean estiraaces of . {

1. particle size for the entire concept, of the dust storm. If pair-
tic le sizes are of the order of 1 mm, the particles can be sus-
pended in the atmosphere for about iOO days and strong vertical
movenents in the atmosphere are not required for protracted per-
sistence of the dust clouds. In this case, the dust stom is a
storm in the common d^nse cf the word only in t fie initial stage, . /IM
but then the wind velocity is reduced and the second phase — the
phase of slew settling — sets in.

p.

But if the estimate of Leovy et al. is valid, arid the particles

are larger, the settling time is only several days and there must |l:

be strong atmospheric movements throughout the period in vzhich '^'..>i

the dust clouds are observed for the dust clouds to persist; -M'J f

■ The optical thickness t =« 3, r =» 10" cm with the density *
p ,a^ 3 g/cm yield a mass of dust in a colur^n 1 cm" in cross-
section of ahout 10 g/cm , which corresponds to a mass of dust
weighing 10 tohs' in the at-nosphere of the entire planet, ^.

3"

A;'

^:

f

c) Effect of .the dust storm on the planetary thermal regime

As indicateol, the s.xirface temperature during the dust storm
decreases.. This is a consequence of the higher transparency cf
the dust clouds for the departing longViave planetary radiatl'on*
than for the shortwave r-^ar radiation. ' It is natural to call
this effect the antigreenhouse effect, since it is opposite in
sign to the greenhouse effect. A semiquantitative analysis of
the planetary thermal balance when the antigreenhouse effect is
present has been presented in a work by Ginzburg /Sl/-

Kifeh-Latitude Clouds • . "

On the 16 February 1972 and 28 Februaj'y 1972 tracks ths ultra-
violet profiles 3hov«ed a sharp rise in brightness upon transiting
the latitude at about 35 -40°. Mariner photographs obtained in '
the same regions, several days later, demonstrate bright clouds
here. These clouds shov; up practically not at all in the near
infrared spectral region, from which the following may be con-
cluded:

1) particle sizes are small (tenths of a micron), and

2) the clouds are entirely transparent to surface radiation
in the far infrared region, and the temperature measured here
pertains to the surface. , - ,

Though the surface temperatures in this region are .close to

' !l ■■

^ the COp condensation point, it is not necessary that the high- ' /15
J* latitude clouds consist of solid carbon dioxide, since here a
%■, temperature inversion in the atmosphere is possible. .From the

.^^ , H,-;0 profiles we can see that water vapor disappears here. Five

2'
to ten microns of precipitated water in the form of small -radius

ice particles can provide optical thicknesses t > 1, occurring

in the shortwave region of the spectrum.

'^

altitude obtained in two Mariner experiments (IRIS, cf . /TC/O and
radio occultation measurements /^^ independently indicate a high
cloud altitude.

b) Sstimate of particle sizes

we will Qv,-ell on this problem in greater detail, since here
there are contradictions betv:een different authors. Moroz et al
^,2,77 give the estimate

*=■:

C&

r ^ 1 \i.m

Pang and Hold indicate a close value £19/ •

r =^ 2 um .

Leovy et al. give a much larger radius /^Q/'-

r =* 10 ^i m

All -three estimates are based on photometric argxiinents. Of
coui'se, dust clouds are inhoiaogeneous in different regions ana at
different altitudes particles of different sizes can be present.
However, the method used by the authors /^O/ raises fundamental
objections. Their considerations amount to the following:

i) The albedo of clouds in the visual spectral region is
small ( = 0.13), which mearis that the albedo of single scatter-
ing is small, and the single-scattering albedo is the smaller,
the larger the particle size. Without presenting their calcula-
tions, the authors /^O/ state that the albedo observed can be
attained only for dimensions of several tens of mJcrons.

2) There ajre photometric and radiometric arguments in favor
of the view that the surface layer conPists of grains several
tens of microns in size. The authors /^O/ believe it is r.atural
to expect that dust clouds consist of particles of the same size.

Both arguments do not appear convincing to us . The same
particles have much linger albedo values of single scattering in
the red and near infrared spectral regions, and the sizes of
, surface layer grains obviously can be much larger than the mean
size of particles suspended in the atmosphere.

14 .

713

4_

f.

h

■&■

REFERENXES" ' /16

1. Moroz, V. I. and Ksanfomaliti . L. V,, Vestnik .A-X SSSR , N"o.

9 {■''972).

2. Moroz, Y. I. and Ksanf omaliti^ L. V., Icarus i2*-f»08 (1972).

/ , ' ,

3. Moroz, V. I., Ksanfomaliti, L. V., Kasatkin, A. M. et al.,

Doklady^ AN SSSR 208 . No. 2 (1973).

4. Basharinov,. A. E. , Di'bzdowskaya , I. B., Egorov, S. T. qfr

al.. Icarus 17? 5^0 (1972).

5. Moroz, V. I,, Ksanfomaliti, L. V., Kunashev, B. S.- et-al., •

Dokladv AX SSSR 208 . No. 5 (1973).

6. More?, V. I,, Ksanfomaliti, L. V., Kasatkin, A. M.,, and

Nadzhip, A. E., Kosinicheskiye issledovaniyA 9. No. b
(1972).

7. Moroz, V. I., Xadzhip, A. E., and Gil'varg, A. B. , D ok lady

AN SSSR 208 . No. h (1973). .

8. Koloso.-, M. A., Yakovlev, 0. I., Kruglov, Yu. M. et al.,

Doklady AN SSSR 206:1071 (1972).

9. Ksanfomaliti, L. V. ^ Pribbry i tekhnika eksperimenta . No. 4,
f .192 (1972). : . .

10. Hanel, R. , Gonr«th, B., Hovis, W. et al. . ' Icarus 1? : 423 -t'
(1972). . ., -

ll.'Hord, C. ¥., Barth^ C. A., Stewart,' A. I., and Lane, A. L. ,
Icarus yj.: kh-y ( 1972). , ,

12. Hovis, W. A. and Callahan, W. R. , JO'SA 56 ; 639,(l956).

'■;■

13. Chase, S.,C., Hatzenbeler, j;, Kieffer, H. H. et al., , »r

Science 121:305 (1972). ' " ' ' . J"

' ' ' ■ ' ■. • ' ' ' ' ' • ' I

14. Lib'erman, A. A., Moroz, V. I., and Khi-otnov, G. S., Astron .

. tsirk. . No. 705, 5 June 1972. ' -

15. Cliore, A., CaiTie, D. L. , Fjeidboj G. et al., Icarus 17 :

484 (1972). , . ' -

16. Tuli, R. G.. and Barker, E'. S., Bull. Atn . Astron. Soc. 4.

No. 3. 11 (1972), • . - I

^

1^ >

17

■ ^ t^" *■' ' -^'^, ^-f

*>'.'*-t ^'1

"X!'

5^_

i&_

A"

■^sr

Moroz, V. I, and Taranova, 0. G,t Astron. tsirk. , No. 697*
10 May 1972.

18. Parkinson, T. D . and Hunten, D. M., Science , jlj: 323'(l972),

19- Pang, K. and Hold, c. W., Marlner-9 Ultraviolet Experlmervt :
1971 Mars Dust Storm . University of Colorado, 1972.

/17-

20.

Leovy, C. B., Eriggs, G. A., Young, A. T. etal.^ Icarus
12:373 (1972). ;

21. Ginzburg, A. s., Doklady AN SSSR , 203 , No. j (l973) .

CAPTIONS' TO FIGURES
Pig. 1. Measurement tracks of Mars -3. /I8

Pig. 2. Results of measurements along' the 15 December 1971

track. Brightness Infrared temperature T„, soil temperature
(calculated from radlofrequency radiation), T„„, brightness
,B (1.4 fi m) j.n the continuous spectrum near 1.4 (xm, dielec-
tric constant of soil e , altitude Z relative to the 6 mbar ,
' level, T^ -- calculated 'mean-diurnal temperature, and ;i, - —
cosine of zenith distance of the sun.

Figs'. 3-7- As above, for the remaining five tracks from, 27 Dec-
ember 1971 to 28 February 1972. •

, Figi 8. Altitudes based 'on 27 December measurements. In the

right part, the altitudes undoubtedly refer to the upper cloud
celling, and -not to the surface. Altitudes along the coinci-
dent section of "the I6 February 1972 track are given by the
dashed line. ' _

Fig. 9. Results of measurements along the I5 December 1971' track.-
The HoO content, pressure, brightness at the wavelengths of

C-, -0 ' . ■

6940, 4940, and 37OO A, M^ — cosine of the zenith distance
of the sun, arid Mo is the ^cosine of the zenith distance of .
the spacecraft . '

"18 '

Figs. -10-14- As above for the remaining five tracks.

Fig. 15. Comparison of measured and calculated temperatures for
the 16 February 1972 track.

Fig. 16. As above for the 28 February 1972 track.

FOOTNOTES
Figs. 1 -7 and 9-l6 are missing.

' 19

,^

31

'^

3

f»,i ^. :s 2:

V

-t — h

v>

cv

C-7

;^

t a •*■■

X

■-55.
h

t.

a'

^
Vi

-

,,_^

«

r-

*^

fv.

'3

^.

u

t

■^

"J

t.

u

r^

\^

"'

1

'J

1)
c

I

o

^ . \ i

X

It

/

1-^

X

N>;.>

M

« i .

«a Co V:

J

N

V

J

I 00

-. — >,

-I ^

— 'X— =--

i
T

,c^

I_

«
J

UJ X

■a- I •' ♦>

->c-

t— i

r. f

H

t_.-J

H-

><

t_

I — ^_

-J

r

fv> I

O

I ^

o

4^f^^

/19

-1
1

4

i'

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1