AFCRL-68-0153: APRIL 1968

ENVIRONMENTAL RESEARCH PAPERS, NO. 285

AIR FORCE CAMBRIDGE RESEARCH LABORATORIES

L. H.ANSCOM FIELD, BEDFORD, MASSACHUSETTS

UV, Visible, and IR Attenuationfor Altitudes to 50 km, 1968L. ELTERMAN

OFFICE OF AEROSPACE RESEARCH

United States Air Force

-$7

AFCRL.68-0153APRIL 1968ENVIRONMENTAL RESEARCH PAPERS, NO. 285

OPTICAL PHYSICS LABORATORY PROJECT 7670

AIR FORCE CAMBRIDGE RESEARCH LABORATORIESL. 0. HANSCOM FIELD, BEDFORD, MASSACHUSETTS

I r

UV, Visible, and IR Attenuationfor Altitudes to 50 km, 1968L. ELTERMAN

Distribution of this document is unlimited. It maybi released to the Clearinghouse, Department ofCommerce, for sole to the general public.

OFFICE OF AEROSPACE RESEARCHUnited States Air Force

VIP

[i

Abstract

An atmospheric attenuation model for the ultraviolet, visible,. and infraredI

was developed in 1964, based on scattering (molecules and aerosols) and ozone ab-

sorrtion. Since then more measurements have been made and our knowledge of

aerosol attenuation has widened. These circumstances result in attenuation model

changes which are relatively unimportant for most exploratory calculations. They

can be significant, however, for long slant-path high-altitude applications entailinglarge zenith angles, factors which characterize, for example, the measurement

geometries of rockets and satellites. Accordingly, a revision of the 1964 Attenua-

tion Model is warranted.

In this paper the optical parameters are computed spectrally and with altitude

as follows: (1) pure air attenuation parameters are determined by utilizing ýayleighscattering cross sections with molecular number densities from the standard at-

mosphere; (2) ozone absorption parameters are derived based on Vigroux's coeffi-

cients applied to a representative atmospheric ozone distribution; (3) seven sets

of aerosol measurements are compared and a profile of aerosol attenuation coeffi-

cients vs altitude is developed. Attenuation coefficients and optical thickness due

to molecular, aerosol, and ozone attenuation are computed and tabulated individual-

ly so that the influence of each can be compared. The newly derived tabulations

permit various exploratory calculations, including horizontal, vertical, and slant-

path transmission at kilometer intervals to an altitude of 50 km, individually for

each attenuating component or for overall atmospheric extinction (molecular +

ozone + aerosol).

iii ,

I

IJ

Contents

1. INTRODUCTION 1

2. RAYLEIGH PARAMETERS 3

3. ABSORPTION PARAMETERS FOR ATMOSPHERIC OZONE 7

44. AEROSOL ATTENUATION 8

5. ATMOSPHERIC EXTINCTION 20

6. 'EXPLORATORY TRANSMISSION CALCULATIONS 20

7. CONCLUDING REMARKS 21

8. TABULATION OiF PARAMETERS 21

ACKNOWLEDGMENTS 45

RE.FERýNCES 47

Illustrations

1. Index of Refraction for 1013 mb and 151C (Table 1) 4

2. Rayleigh Cross Section vs Wavelength (Table 1) 43. Representative Atmospheric Ozone Concentration l'rofil,2 (Table 2) 74. Aerosol Attenuation Coefficients vs Altitude at = 0. 55p 9

Illustrations ; /

5. Single Profile I3u(h, AI) for 11 April 1964 ft 02:00 MST, Similar toMean of 79 Pofiles 1i

6. Single Turbidity Profile A3p(h, X )/Pr(h, A) for 11 April at 02;00 MST 12

7. Mean of 79 Low Stratospheric Dust Profiles (Table 3) forApril 1964 to April 1965 14

8. Mean Turbidity Profile #3p(h,..X1)/5r(h, '1) 15

9. Expanded Scale for 26 to,32 km Altitude Region Showing Hp 3.75 kmfor 79 Profile Mean p 16

10. Comparison of Profiles 1711. Aerosol Attenuation Coefficients pp(O, X) vs Wavelength at Sea Level

for a Meteorological Range Approximating 25 km 19

Tables

1. Model Parameters as a Function of Wavelength 2

2. Model Parameters as a Function of Altitude 63. Aerosol Optical Thickness as a Measure of Volcanic Dust, X = 0. 55gi 13

4. Parameters at 0.27p to 4 . 00 (Tables 4. 1 to 4.22)

vi

-iA

I /

S~Symbols

A. Vigroux ozone absorption coefficient (cmat ) S bD Ozone concentration (cm/kin)

d Horizontal path length (kin) pH Aerosol scale height (kin)

ph Altitude (km)

K Mie scattering efficiency

m Aerosol index of refraction

m Index of refraction at sea level, air at 1013 mb and 150C

N3 Ozone number density (cn 3 )3-

N Aerosol number density (cm

N Molecular number density (cm 3 )

N Molecular number density at sea level (cma")

r Particle radius (microns)

t Turbidity (3prT Temperature °K

Th Horizontal transmission

T0h Transmission between sea level and altitude h

Th-.v Transmission between h and space

T Ah Transmission between two altitudes above sea level

13~ Atmospheric ozone absorption coefficient (kmi)

1p Aerosol attenuation coefficient (kin1 )

(h, X)Mean of 79 profiles for X 0.55 microns (kW")

vii

-',

O•r Rayleigh attenuation coefficient (kmn

""3ext Extinction coefficient (kmi) ¶

•"I L)epolarization factor

!. Zenith angle

Wsvelength (microns or cm)Wavelength 0. 55 microns

ar Rayleigh scattering cross section (cm 2)

r3 Ozone optical thickness from sea level to altitude h (0-h)Ozone optical thickness from altitude h to space (h-,) Y'

T Aerosol optical thickness from sea level to altitude h, (0-h)pC Aerosol optical thickness from altitude h to -pace, (h-o)-p

r Rayleigh optical thickness from sea level to altitude h, (0-h)

r Rayleigh optical thickness from altitude h to space, (h-') IS~r~ext Extinction optical thickness (molecular + ozone + aerosol)ext from sea level to altitude h, (0-h)

7t Extinction optical thickness (molecular + ozone + aerosol)from altitude h to infinity, (h-m<.1

Aerosol size distribution function

Vl

viii 4

S,?

UV, Visible, and IR Attenuation for Altitudes to50 kmn, 1969"

I. INTROIDIUCTION

In 1964, an atmospheric attenuation model was published (Elterman, 1964)

which has'been useful for a variety of exploratory calculations. Now a revision is

warranted for reasons given in the abstract and Section 4 of this report. In this

revision most of the earlier material is presented in summary form. The section

on attenuation by Rayleigh scattering, however, is retained because the content

leading to the derivation of the Rayleigh parameters is useful. In one instance,

due to existing interest, the material is expanded, i.e. , the tabulations which com-

prise the attenuation model now include aerosol and ozone optical thickness so that

a comparison can be made of the relative importance of each attenuating component

for vertical and slant paths.

The shortest wavelength considered is 0.27 microns. The use of shorter wave-

lengths would require a treatment of 01, absorption. Also, attenuation is suffi-

ciently severe so that interest in the shorter wavelength region for purposes of

ultraviolet transmission below 50 km probably is limited. The longest waivelength

used is 4.0 microns. Calculations for longer wavelengths are complicated hv the

presence of absorption bands of I110, CO),,, and their wings. In between, n total

of 22 wavelengths is chosen (Table 1) within the atmospheric windows and for the

ultraviolet region where ozone absorption is important.

(1leceived for publication 25 March 1 )(I)

2

Conceptually, the attenuation model starts with moleculardensities from thelatest published U.S. Standard Atmosphere (1962) followed by the addition of ozone

and aerosol components. The meteorological range (M.R.) at sea level correspondsto about 25 km at 0. 5 5p wavelength. This choice serves a useful function because

it permits including some important measurements conducted at X - 0. 550 . Inaddition, this wavelength customarily represents the phototopic region.

Table 1. Model Parameters as a Function of Wavelength

A (microns) m5 a or (cm 2) A (cm"I)26 2

0.27 1.00029668 8,960 X to-26 2.IOX 10 20.28 1.00029475 7.646 X 10- 1.06X 1020.30 1.00029156 5.677X 10- 1.01 X 101

-260.32 1.00028902 4.310X 10 2 6 8.93X 100.34 1.00028699 3.334 X 10 26 6.40x Xo2 I I0.36 1.00028531 2.622X 10 26 1.8ox 10o3

0.38 1.00028392 2.091 X 10-26 00.40 1.00028275 1.689 X -26 00.45 1,00028052 1.038 X to26 3,50X 10-

0.50 1.00027896 6.735X 0-27 3.45X 1o 2

0.55 1.00027782 4.563X 0-27 9.20X to20.60 1.00027697 3.202 X 10 27 1.32 X 1010.65 1.0002763.0 2.314 X 10 2 7 6.20X 102

0.70 1.00027518 1.714 X 10" 27 2.30X 10'2

0.80 1.00027503 9.990 X 10- 2 8 1.00 X 10- 2

0.90 1.00027451 6.213 X 10 2 0

1.06 1,00027397 3.216 X 10- 2 8 01.26 1.00027357 1.606 X 10- 28 0

1.67 1.00027315 5.189 X 10"2 9 0

2.17 1.00027292 1.817X -29 03.50 1,00027272 2.681 X 10-30 04.00 1.00027269 1.571 X 10- 0 0

- Wavelength

ms - Index of refraction (1013 mb, 15°C)

or - Rayleigh scattering cross sectionAbsorption coefficient after Vigroux for pure 03., smoothed

v values (1013 mb, 18*C)

4AI

3

2. RAYLEIGH PARAMETERS

A fundamental requirement for generating an accurate series of Rayleigh

parameters is an exact dctcrmination of the index of refraction for the wavelengths

of interest. With this known, the Rayleigh cross sections can be computed. This

in turn permits computation of the Rayleigh attenuation coefficient and its variation

with altitude as well as corresponding optical thickness values.

The index of refraction for a standard atmosphere (1013 mhb, 15°C) specifically

for the desired wavelengths used is determined by Edlen's (1953) expression

(ma 1)10~ .- 6432.8 + 2949810 25540146 - 0)7) 41 - -2)

where m. = refractive index

X - wavelength (microns)

Penndorf's (1957) computations using Eq. (1) demonstrate that the effect of water

'vapor can be neglected and'the derived m 'values have negligible error for the

spectral range from 0. 2 to 20.0 microns.

The R•ayleigh cross section is expressed by

3 - (2)

where

r ' the Rayleigh scattering cross section (cm 2 ),Sthe wavelength (cm),

'Me a the index of refraction of air at 15C and 1013 mb pressure,

N a the molecular number density at sea level for a standardatmosphere (cm- 3 ),

6 a the depolarization factor.

The term (6 + 36)/(6 - 78) accounts for the degree of depolarization attributable to

the anisotropy ofthe atmospheric moleculb,. The depolarization factor has been

determined by-calculation and by laboratory measurement. The latest work of

Gucker and Basu (1D53) yields 6 - 0.035 . The wavelen4ths of intereHL with Ohw

indiceF of refraction and Rayleigh cross sections [computed frnm I'Pqs. (1) and (.))j

are listed in Table 1, and plotted in Figures I and 2.

Using the scattering cross sections, the linyleigh coefficients art obtained

with

4

1.00030 -- 1 -rTFFT-r1T

1.00029

3 1.00028-

1.0002 I I I 01

1010( WAVELENGTH (MICRONS)

Figure 1. Index of Refraction for 1013 mb and 150C (Table 1),IoTO RepreSent Attenuation Model Wavelengths

IOC0-26

10-27io2

10 30 1 1-2 1 1

WAVELENGTH (MICRONS)

rigu4re 2. Rayleigh Cross Section vs Wavelength (Table I),uouo Represent Attenuation Model Wavelengths

II

r •MX) r 00 N r(h) (10 cm/kr) (3)

where

Or = the Rayleigh attenuation coefficient (km"i)

Or 2 the Rayleigh scattering. cross section (cm2),

N r * the molecular number density (cm- 3)

The values of N (h) needed for Eq. (3) were obtained from the U.S. Standardr

Atmosphere and are listed in Table 2. This expression is used to compute an array

of Rayleigh attenuation coefficients as a function of altitude for each wavelength.

With the Rayleigh attenuation coefficients determined, the optical thicknessesfrom sea level to some altitude h are computed by

h

Tr(h,,) - )".r(hx)Ah , (4)

0

where5Tr* Rayleigh optical thickness (0 - h)

r mean of the Rayleigh attenuation coefficients (kmfor each altitude increment,

A h altitude increment chosen as one km for the.e calculations.

The Rayleigh optical thickness for altitude h to space is obtained by the rela-

tionship

r I (h X h r ,- 1r(hX) , ()

where

7(h) a Rayleigh optical thickness (h-)

r() = Rayleigh optical thickness (0- a* )'

r0km Abv80inStrlt(96cacltosbaeonN, adThe term rr(oo) was obtained by using Eq. (4) with the limits set between 0 and-80 kmn. Above 80 kmn, Stergis' (1966) calculations, based on N 2- 0 2 ,and 0 s

the principal atmospheric constituents, yield

. 0-6 , ), = 0. 4;f. pr(h,),) d 6. 7 •.X 107 X =0.61A

80 2.1X 10-7 X= 0 . 8M

These values approximate a constant 10" , that of the Hayleigh optical thickness

for unity air mass. For our purposes then the integral can be neglected because

the constant is small and applies to all wavelen-",q of interest.

Table 2. Model PnranspterR mR a Function of Altitudc

h (kim) Nr (cm" 3 ) D3 (cm/km)r 33

0 2.547 X 10 1 9 3.56 X 10-ý1 2.311 3.26 ,2 2.093 2.933 1.891 2.504 1.704 2.265 1.531 2.216 1.373 2.167 1.227 2.238 1.093 18 2.289 9.712 X to 2.81

10 8.598 3.5011 7.585 4.6012 6.486 6.2113 5.543 8.4514 4.738 9.5715 4.049 9.94 -216 3.461 1.03X 10 2

17 2.959 1.1118 2.529 1.2219 2.162 1.4220 1.849 1.6421 1.574 1.8422 1.341 1.97

2' 1.144 17 1.98,24 9. 760 X1t 1.9325 8.335 1.8026 7.123 1.6327 6.092 1.4128 5.214 1.2329 4.466 1.0730 3.828 9.03 X 10 3

31 3.283 7.9332 2.818 6.8233 2.406 5.8234 2.056 4.8535 1.760 4.3136 1.509 3.6137 1.296 3.0238 1.110, 16 2.5339 9.620x to 2.1740 8,308 1.86

41 7.187 1.5242 6.227 1.19 443 5.404 9.30 X 10 4

44 4.697 7.4445 4.088 5.7646 3.564 4.4647 3.112 3.5348 2.738 2.7949 2.418 2.2350 2.135 1.86

h- Altitude; Nr - Molecular number density;D 3 - Ozone equivalent thickness

1 73. ABSORPTION PARAMETERS FOR ATMOSPHERIC OZONE

This section is a summary of the material used in the 1964 Attenuation Model.

The parameter for determining 03 absorption as a function of altitude is the

atmospheric ozone absorption coefficient expressed by-

3(h,) ( , (6)

113 = atmospheric ozone absorption coefficient (km 1 ),

AV the pure ozone absorption coefficient (cmn ) after Vigroux,

D the ozone equivalent thickness (cmakm). .

Thus, the Vigroux coefficients (1953) listed in Table I in conjunction with the ozone

concentrations, Table 2 and Figure 3, permit the computation of an array of atmos-

pheric ozone absorption coefficients to 50 km for each of the desired wavelengths.

40

TOTAL OZONE&O.S5cm

F/

0 4 8 12 16 20 24

03 (cm/km x 10-3

Figure 3. Representative Atmospheric OzoneConcentration Profile (Table 2). Values for:0 to 30 kin, based on Handbook of Geophysiles

and Space Environment (1965)30 to 40 kmn, interpolated40 to 50 kin, based on London, Ooyama, and

Prabhakara (1962)

I

8

The ozone optical thickness from sea level to altitude h, 7 3 (h 0 ), and the

ozone optical thickness from some altitude h to space, r'3(h,7,), are included in

alie model tabulations. 4'I ne expressions for deriving these parameters have the

same form as Eqs. (4) and (5).

4. AEROSOL ATTENUATION

Of the various methods used to investigate aerosol attenuation, for the present

we will consider optical techniques only because they are suited to this type of study.itl In this country, Newkirk and Eddy (1964) used solar aureole photometry; Penndorf

(1954) analyzed solar radiation measurements from aircraft altitudes; Elterman's

results (1966a,b), with searchlight probing, comprise a substantial number of pro-

files acquired in New Mexico for altitudes to about 34 kmn. In Australia, Crosby

and Koerber (1962) used a balloon-borne integrating nephelometer. In the U. S. S. R.,

"Kondratiev, et al. (t967), conducted balloon solar transmission measurements;

Feoktistov (1965) analysed photographs of the earth's horizon from the spacecraft

Voschod; Rozenberg, et al. (1960) (1966):, acquired their results with searchlight

probing. 'rhe various pesults, as shbwn in Figure 4, were made comparable at.

;k - 0,. 55j& by using ,tKt empi.cal relationship that the aerosol attenuation codfft-

cient is inversely prlo ptrtidnal to wavelength. For reasons of clarity, a substantial

body of results W0 not included in Figurq 4,'as for example the twilight measure-

ments by Rosenberg (1965), Volz and Gocidy (1962), the searchlight measurements

by Spankuch (1967), analysis of twilight aýreole photographs from. the spacecraft

Vostok-6 by Driving (1966), the aircraft measurements of sky brightness by San-

domirski, Altovskaia and Trifonova (1964), and aircraft nephelometry by Waldram

(1945). Also, interesting results in the form of relative values have been obtained

with optical techniques: the twilight measurements byBigg (t 964), the laser beam

backscatter by Collis and Ligda (1966), by Clemeshaw, Kent, and Wright (0967),

and by Grams and Fiocco (1967)..

A consideration of all results shows, \as does Figure 4,. that the aerosol atten-

uation coefficient is a strongly fluctuating parameter and that average values based

on an adequate number of measurements are necessary in order to establish a repre-

sentative profile. The recent searchlight probing measurements (Elterman, 1966a

and 1966b) appear representative based on several considerations. First, each

profile was acquired by continuous measurement through both troposphere and

stratosphere and.with an altitude resolution approximating one km. In addition, a

total of 119 profiles comprising absolute -values of aerosol attenuation coefficients

were determined for various times throughout the year. This represents a sub-

stantially larger sample than previously published. Further, such a quantity of

,*1

9I10 7.-IIII

0

0

0 00++ AA

I&.O46+ A

* OoX++

o• • + ..-104 X4

U. x ,OA

A C"A++

Z X +++

W +0 40

L1J~~ ",,X44+ •

xx O

0 / 5 10 15 20 25 30 35

"• ALTITUDE (kin) O

Fire 4. Aerosol Attenuation Coefficients vs Altitude at 0. 55p.Co parison of results:x X X solar aureole, 2 balloon flights, Newkirk and Eddy (1964):

' solar radiation measured from aircraft, mean of 8 flights,Penndorf (I.954);

+ +++ + searchli ht probing, mean of 105 profiles, Elterman(1966a) and (1966b);

"me w ® balloon integrating nephelometer, mean of 14 flights, Crosby/,, and Koerber (1962);*,so e•a solar radiation measured from balloons, mean of 3 flights,/ .., Kondratiev et al. (1967);\spacecraft horizon photography, analysis of 4 frames,: Rozenberg (1966),

oeoktistov (l965);

/ o d,o searchlight probing, mean for 5 nights, lHozenberg (1966)

14.i ,

10

results readily permits statistical treatment. Finally, we note that the mean of the

119 profiles falls reasonably well within the values determined by other researchers,

a circumstance which tends to provide a meas.ure of comfort.

In considering the suitability of the 119 proofiles, ýextensive averaging is re-

quired and this tends to wash out features easily noted in the individual profile.We present, therefore, in Figure 5 a single profile, chosen because its properties

are readily evident and also because it is similar to the overall average. The fea-

tures can be made to emerge more prominently if the aerosol coefficients are used

to compute a turbidity profile, tp(h,1 I7N p (h, X )/Or(h, X) , where 0P and Pr are

the aerosol and Rayleigh coefficients respectively and X I 0. 55w (Figure 6).

Since volcanic dust in the atmosphere can have a residence time of several

years, the effects of the Mt. Agung eruption (March 1963) must be considered.

'The direct measurements of Junge, Chagnon, and Manson (1961), Friend (1965),

Mossop (1964), and Posen (1968), collectively considered, before and after this

event, show evidence of change in the stratospheric aerosol content. The observa-

tions of the twilight sky by Volz (1965) and Meinel and Meinel (1964) also show

augmentation of stratospheric particulates. Since the searchlight probing measure-ments yielded absolute values of aerosol attenuation coefficients, the most suitable

parameter to use for examining this feature quantitatively is tne stratospheric

aerosol optical thickness for the altitude region between the tropopause and 25 km.

The reason. for choosing the latter altitude limit will be discussed later, Accord-

ingly, all profiles were placed in time-sequential groups determined by the simi-

larity of the stratospheric-dust feature. Then the optical thickness was computed by

n 2

1F IN A p( h ,(7)

iml' hI

where n is the number of profiles in the group, h1 is the altitude of the tropopause,

h2 the 25 km altitude, 1' the mean aerosol attenuation coefficient (within each pro-

file) for the altitude interval, and Ah the altitude intervals used for computing

the profiles. The results of this computation are presented in Table 3. The tabu-

lation demonstrates a relatively high level of stratospheric dust for the December

1963 to March 1964 period. Beginning with April 1964, dust abatement and a gen-

erally stabilized level are in evidence. The mean optical thickness of Group (B+C+D)

is 26 percent less than that of Group A. Since Group A entails a period of abnorm-

ally high aerosol content, its profiles are not representative. These results are

in satisfactory agreement with the findings from the direct measurements of the

authors mentioned.

/

+ + +I+ +

i+

4'

20- +++

S1 ÷÷÷AEROSOL +++•:!.--. MOiECULAR :

30 -4.• ''•4N.

2 +

20

10-6 10-5 104 10-3AR O

ATTENUATION COEFFICIENT (krn"1

Figure 5. Single Profile]p,(h,? It) for I I April 1964 at 02:00 MST,Similar to Mean of 79 Profiles, XI w 0.,55,Surface to 5 kmn- convective region;5 to It.7 kmn- troposphere dust layer;

It. 7 to 23.,8 kmn- stratosphere dust layer,25.6 km - upper altitude maximum. . A E aerosol (measurements)

S molecular of pried)moeua computed)

i12

40 -

30 -4,

+

30- 4.

25- 4.44,

+

4..

taJ +

Is2_ 4-4

+ 4. 4 -.

++

10- +÷•, • • ÷ ,4.

4.4

S4 -.... 4 ,.4.

00*~ TURBIDITY p$

Figure 6. Single Turbidity Profile fi (h,;k )/0(h,),1

P' t

for It April at 0200 MST.+++4+ Measurements,(See caption pertaining to Figure 5)

oI.,

13

Table 3. Aerosol Optical Thickness as a Measure of Volcanic Dust, XI- 0. 5 5 jM

Period Number of Mean Optical ThicknessGroup (Inclusive) Profiles (approx. 12-25 kin)

A Dec 1963- Mae 1964 40 3. 1 X 10-2

B Apr 1964 50 2.2

C Oct 1964- Nov 1964 10 2.7

D Dec 1964-Apr 1965 19 2.4

B+C+D Apr 1964- Apr 1965 79 2.3

The considerations discussed above Justify the selection of the Group (B +1D)

profiles as a basis for developing representative aerosol attenuation pararnete'rs.

It will be convenient to designate the 7d profile average for X 1 0 O. 55 P as

p(h,l) (Figure 7). This profile can be extended to encompass a larger altitudep

range by using the scale height relationship,

p t3( 2 0% 1) ~~h2 ,x I exp - H2 h (8)p,.

Penndorf's study (1954) shows that for the lowest 5 km, the aerosol coefficients fall

off exponentially with a scale height 0.97 < I < 1.4 km. We resort to the use of

his mean value, Hp -1.2 km,' to extend the 9 (h1, X profile from 3.7 km to sea

level. This results in aerosol coefficients which are identical to those of the 1964

Attenuation Model for altitudes 0 to 3 km (Table 4.11).

Above the convective region, up to the tropopause the aerosol coefficients show

a moderate gradient which is in close agreement with Penndorf's analysis (1954) of

the vertical distribution of aerosols in the troposphere. Also, this section of the

profile is based on high signaJ to noise measurements and extensive averaging,

factors which contribute to its reliability. Additionally, this altitude region, being

above the convective layer, is cuiaracterized by aerosol conditions which tend to be

independent of surface terrain. These considerations suggest that the shape and

values of the p(h, XI) profile for this altitude region are realistic.

Above the tropopause, up to 25 kin, the coefficients are larger than those de-

rived for the 1964 Attenuation Model by a factor of about 20 (at 20 km for Xl 0. 5 5P ).

This difference may be attributed in part to the intrinsic difficulties of converting a

size distribution to an optical parameter, that is, establis hing the radii limits,

particle shape, chemistry, and index of refraction. H,' itiv, to profile shape, a

turbidity maximum dominates at about 1.) km ( I'igure 8). '[lie measurenients of

Rosen (1968) and those of Volz (19611) for 1.964 to 19611 are, in smtisfactory agrecr1.ent

I

4'm

14

lot

T 4,

4. ,.4 ÷i

eillCQ"II

. M.4

35, ,

II4.

4,

30- 4

44

Ol 20O

25 +

+

4o

15 -

S4.

20

Fiur 0. MenTridt rf

* 1 ( )4)

( t F

4,.

10 44.4.

4.4.

o - , 4. 4. . .

0 I.0 2.0 3.0TURBIDITY ,Gp/•Gr •

Figure 8, Mean Turbidity Profile, •p(h, X)/1 3(h,•l(See caption for Figure 7) Par

16

with the mean optical thickness and shape of the Group (B ýC+D) profiles. Table 3.

Afin their resultR ghow that the stratospheric dust level has remained approximate-

ly constant from 1964 to the time of this writing. The ý p(h,AI) curve (Figure 7)

shows this dust feature as the knee of the profile rather than a massive layer fea-

ture indicated by the turbidity profile. This conceptual relationship suggests thatover-emphasis is possible when dealing only with turbidity profiles.

The turbidity profile shows an upper stratospheric maximum with its lower

terminus at 25 km. This altitude then, was the basis for choosing the upper strato-

spheric dust limit in Eq. (7). The maximum at 26 km occurs with sufficient fre-

quency to be easily identified in the turbidity profile. The existence of such all

aerosol concentration above 20 km is supported by the analysis of satellite photog-

raphy reported by-Mateer, Dave, Dunkelman, and Evans (1967).

To establish upper altitude aerosol coefficients, a least square fit was com-

puted for ý (h,X 1 ) from 26 to 32 km (Figure 9). The result, Hp = 3.75 km (in

effect derived from 790 measurement points), was used in Eq. (8) to extend the

values to 50 krm. Miller (1967) obtained H. = 3.25 km from a thorough analysis

of rocket measurements acquired in 1964 for this altitude region. The overall

profile from sea level to 50 km is presented in Figure 10 (Table 4. 1 t). Since the

lo*'S , I I i I I '

"I10,,

S,-

4n02 26 28 '30 32ALTiTUCE (kin)

F'igure 9, E;.xpanded Sc~ale for 26 to 32 km Altitude RegionShowing lip = 3•75 km for 79 Profile Mean; AerosolAttenuation Coefficients, I3D(h.X 1 ) va Altitude; LeastSquare Vit Used to Extrarolate to 50 kin; X'7 --9.5

I' S 17

50 .

MOLECULAR

40

530

AEROSOL AEROSOL20 1964 ~19683

10-

ATTENUATION COEFFICIENT (ký'

liigure 10. Comparison of Profiles. Aerosol attenuation coefficientsPp(h, Xj) , with molecular gr(h. Xi). The 1964 profile shows interpola-tion between 5 to 10 kin; X10 55

18

turbidity is proportional to the mixing ratio, the diminishing values for the extrapo-

origin, the mixing ratio would tend to be constant or increase for altitudes 30 to 50

km.

Thus far we have selected a set of measurements for X, - 0.55p and provided

reasons for 'ts use. It would be in order now to examine some expressions leading

to corresponding aerosol profiles for other wavelengths. If we consider a real

atmosphere, the aerosol sizes within unit volume can be described by a size dis-

tribution function, * (r) . Various size distribution functions are in use: the Junge

type power law (1963) with a choice of exponents discussed in detail by Bullrich

(1964), a similar distribution modified by gaps observed by Fenn (1964), a log-

Gaussian distribition used by Foitzik (1965), a composite distribution with com-

ponents from several types. The optical-particle size relationship utilizes O(r)

such that

N

p(mr,,) -f Ia(m,r,X) dN(r) (9)p p p

N

dNp -N 0 O(r) dr (10)

No(h) C Np(h) . (11)p

1P is the aerosol attenuation coefficient, m is the index of refraction, Nrl and

Nr 2 are the aerosol number density limits established by the radii limits r 1 and

r2 , ap is the aerosol cross section for each particle, Np is the total number of

particles between r 1 and r 2 - For a given altitude, N actually is proportional

to the particle number density-between r 1 and r 2 . Since the same size distribu-

tion function applies to all altitudes (an assumption), Eqs. (9), (10), and (11) are

combinedr 2

p(hA) = CN (h) f op(rX) d(r) dr . (12)r1

Here, C N p(h) is placed outside the integral which now contains only factors that

are independent of altitude; also, m is removed because subsequent considera-

tions will pertain to particles without any distinction in refractive index. If

Eq. (12) is normalized to sea level conditions, the integral cancels out. Then

generally for the various wavelengths X, and specifically for 1= 0. 55p we have

II

N!j3.._(h,)X) &_(h. X,) N (h) (3

or

Pp(hX) p (0, . p(h,A1) (14)

Equation (13) has been derived in this manner to demonstrate its compatibility with

particle size considerations. Sea level conditions have been researched extensively

by Curcio and Durbin (1959), Curcio, Knestrick, and Cosden (1961). Knectrick,

Coaden, and Curcio (1961), Dunkelman (1952), Baum and Dunkelman (1955). The

P,0(0,X•) values for a 25 km M.R., based on the results of these authorsare shown

in Figure 11 (see also Elterman, 1964). Utilizing these results, in conjunction

with the Ip (h, k1) profile (Table 4. 11), all requirements for the right-hand side

of Eq. (14) are satisfied and an array of aerosol attenuation coefficients can be

computed for all altitudes and wavelengths of interest.

The aerosol optical thickness from sea level to altitude h, r (h, X) , and the

aerosol optical thickness from some altitude h to space, .'(h, X, are included inp

the model tabulations. The expressions for deriving these parameters have the

same form as Eqs. (4) and (5).

i~~~~~ Sxl' .... - ,I

r If ! "

5 X 10"

16.1

2K1020.1 0.2 Q.3 0.5 1.0 2.0 4.0

WAVELENGTH (microns)

Figure 11. Aerosol Attenuation Coefficients •u(O, ) vsWavelength at Sea Level for a Meteorological RangeApproximating 25 km.A - derived from Baum and Dunkelman (1955)B - contained in Curcio, Knestrick, and Cosden (1961)

20I

. .V%0SIOPIIERIC EXTINICTION

In this section, three sets of extinction parameters are considered: extinction

coefficient, extinction optical thickness from sea level to a desired altitude, and

extinction optical thickness from a desired altitude to space.

The atmospheric extinction coefficient ext is the sum of all the attenuating

components:

•ext(h,?,) Pr(hX) + 003(h,A) + Ph,•) .(15)

The extinction optical thickness from sea level to altitude h , Next(hX) , and

the extinction. optical thickness from some altitude h to space, rTxt(h,X ) , are in-

cluded in the tabulations of the attenuation model, The expression for deriving

these parameters has the same form as Eqs. (4) and (5).

6. EXPLORATORY TRANSMISSION CALC•IATIONS

Using the derived tabulations that follow, some explopatbry calculations withextinction parameters (for any of the wavelengths) are,/demonstrated. Rayleigh,

aerosol, and ozone parameters can be used similarly.

For horizontal transmission (Th) over a path (d) at any altitude (h) , the ex-

tInction coefficient

STh exp [ -Pext f(h,X ),d d (16)

For -vertical and slant-path transmission from sea level to a given altitude,' at

zenith angle a for all wavelengths of interest

To- = exp [- Tet (h) -seae] (17)

For vertical and slant-path transmission between two altitudes above sea level

T Ah ' exp - [ext(h2) - 7'ext(hl). sec 0 (18)

For vertical and slant-path transmission from a given altitude out into space

T =x e'xt(h) sec 0 (19)

/

I

21I ~~7. C:ONC:LUDlING REMARKS•

The procedure for developing the aerosol attenuation profile is summarized as

follows :

(1) Various studies were compared and of these a set of measurementsselected.

(2) The choice of measurements (comprising 119 profiles from 2.76 to 34.4 kin)

was examined statistically. This resulted in the elimination of 40 profiles

(December 1963 to March 1964 inclusive) characterized by a high volcanic

dust component.

(3) The mean of the 79 remaining profiles was extended to sea level and to

50 km respectively by reasonably supported extrapolations.

(4) The overall profile then was developed laterally to obtain 21 additional

profiles for the wavelengths of interest.A significant aspect of the procedure is that the wavelength--height array of param-

* eters was derived independently of the assumptions associated with conversion of

a size distribution to an optical parameter.

For most purposes, calculations using the new parameters will be affected

only moderately. For example at X 0,, 55BA , the 1964 Attenuation Model providesan extinction optical thickness, text 0. 331, for a vertical air mass. The new

parameters yield Text = 0.379, resulting in a transmission change of about 3-1/2percent. However, for long path horizontal transmission calculations above 5 km

and for long slant-path calculations entailing large zenith angles, the new aerosol

parameters can function more significantly.

As mentioned previously, the Hayleigh and ozone parameters are unchanged.

8. TABULATION O' PARAMETERS

Tables 4r1 to 4.22, which follow, comprise the atmosph.eri- attenuation model.

Exponents are in computer notatlona for example, read 2,86-3 = 2.8 8 X 10 and2.86 3 as2.86 X 103

.I

22

eSINiOO *P-AS~mm '004 A.edni-c mcaMn"ý ýalw Ný

po WN$g4 R N W

-4 - tv Mecc c eec. . e0g. ... 0c eP~. .. t. Pc. P.Rc11- ..r-PP ....

$f ea se so . * i Ott.UP.4 eesc am$$~~ to4 e1*5N0@ J . 1154 .41A..

ao le In n,# W~ce 10lcN* Od14.

PRO FcWAe.ceC-".M1610 N# SýN~cf, NOe6...S. cOIA "#

t.i A 0. 0 GO in aN a,4" 00 P .4. vi N4 A -4 VI 0#4 MV51.1.5140 14 w15 & P.. P.. 0 0

w e 1. 1 5 5 0MeF .0a4 C w , .00, N assssll

0 a 0 1aa 490041 09 0404 640, d4I

P.i ,MU n0%M f nM t W

0 as i S ~u ii88l. of 6 610at 41a g 0.a.

.ec 4c Re N1ac t. cN..4 c" cceVeccc4cPe *00 Remf RYI. ece"4ý? eccOreceece # 1

I. O0015114.6.a~00d-sNN

W, 1- 0 4missl.1 iss Nos~ 1i 5555 ii5551ms

N ~1 N or -d t4o -d -N -N fMl &l 114 K 1N---aP I1 ~ 1 14 N 04 #4 04~55 ~N--

*01 d 0~.cceI 110 0. 9 0 0 0 a 4.15N onnP. 0 0 5.51 1.0 * P 4 .10 If 9-0-1 1111 N NN N

0,. 04 t. miI# INr - 14 W~ 0 IN .J1'C -M. f, 0 1 - 1& 4mI I..NNN N 0 0 Nr nN

wt.S* 51 air 4.91 M0A 1 NP.' ow,4 4 'AN 44IfI N4

~4.-R4.4NNNNN~lNAR~N15NNNN11N.N M5111111111d4.d4*4,#4*4 v

23

U.~~'O P.-4NIAI0pO~~.~ 2.0,4A 2 SC4 ~A a .. 0 AmM* .4 Ina@1'4% M 0NO % #InIAIAIAN Ia- We 0 0 m l 4

4,; 4

d.4 .4.d 4,4 -0414.4.4 .0.4.0.4000 0 @00 00 0 00 0 00 4 . i4NNNN N

Silgil IglI ~ ~ 6 eelso fe lgSIoOS j~~

fel fft 4 " MA 011 OR# W% P-I ~I 0- . dd W.W d.W- .4d,-4 -4 -4 01 0 1. 4 kA# M IA E No N1 .4 . 0 0 #0 0A'J*i.

o *eP Ore%~A A0-I' A. N . NA46 .g A.44IA0.0N A O 400% P OP -W 0' 1" wO 4 ANI N ap* 4 A 0 0

0 ~ ~ i Me IAI A4 *I I AI N N~e P01 go- IA 4 No 0a0 N ý 0. *0 IA4 IAN -AIA I IAIA A I IAIA A I IAIA A I IAN N N N N N N .. C..

o .0 0S .00*MA4 ma N.Iol *'AiA@ a I N P.4'O m IAA A m -0a N 4 '01 P O a. 8v"4.4. NNIAIAMONOp*a &C4..IA4N. a 4IIIq4IIAIIIIIVI

.04 ..4 dll 0000 00 00 00000 0 *.4I d-1.4 Q.d NNN 4- r'F N'N

orN m 0# 4N0A.40 0 .g 0 0" on @0 a M Ia- m4-ImA.*N A NAPN . sm.40'

A 414 4 III No 140 Im 04.0 .4 .I*4-W , dwNNNr y 4.4. .4 d.4,0 in' -.I 41 -NN41 N4INO

04

N %N M N Al1. AP 9.. N I I .A N 0 NNP.V -N O S*AO% 'A 0NN NN N

00'. IAn 4 A P I N 6 I A N N In ~ Nl in V M 0 ..0 adI NP 0D N N P d4 WA NI A A N .4 Nd .40 IAin IA 6 n I A P S P .04 .4

W, a 4 " .evImon & s d 0 15 P. a, ,aN1.- 9,N N.1-WA 4 N ,N0IIA 1 4 0 1- 4 W% 0 OItAN 4N 14gee~1.4 0ge...eg6O@*eg~ee.ge~e~tC

top.,IIAAAIIf44 .1.10.NN N~ IA . .C 4 AI N~

I~~fl~r to tmG.4o eI0I*A, 0 be.4ANIIA464AA I AANNI

*.rfIAO0IA~lIA-N I044O~# .0Id.4IAIANN444~OO000 01# 4",00

IAI .. 4 . .4 d .NIAIA 44 4.-f 4 AIA4 4 -4 4 -4 40 O 4 . . 4 ' . O 0 '

Il ) t i l

4...C. N N%11 N VN 9 I lo ON0N ?'

24

6A e I4IO~~- I~Op AN~ 4 lo * 4v? 4

-C4. . N0 VTT r~ a.4 V o - a04* -NN N7 .wN "fm A A*

*Ea.Na-. aa a-, m aNNNov .ai

a 1 A . 0N 1. -NN' *IA 11a A a i N~ F. A .4 0A 4p N 4O O A 4551 A 4 ?.. 0 N4

0 C, 6, N4 N N

.1 4 4 4 4 y 4 , A CS C .1S 46 55 C "1 AIAS"

Am Aa 'al agalga #ll a A -a a 1 1 a a ea aa '1 aa10a1

N.4in 0P A N0 *A 0F_4N .2* 1.045I NQ m N N45e45 a. S.044 Na.4

1. 0. .4...-. -1. 1. .C*2,

f"k A 00, *n 4 0164, 0:W, Pl.. W. 0

A 4 .4 N .fnt Cn - CD .0 5% *455 N I. # 4 0, - 1 440 C 5.O "* A c. P. N N7 N 'A . 4 -an0 .0 P .- M% 0 e141 N" -t in 01

.44N N4- N4 N44 N.4r4NN N N N f" f," 4545 51" 445 454 4j 4

25

j 1' 0'4!1 N"IDN 1:c4A .",N *0q0ce4104 I 4,02*.4Q.4 InON4e4 1el 4.4 -01,t ReA IeON.411 R

**~* *** ** g* g 6 of too * 1* go** g*to *gilgg0,1gc *e g..ec.4-4.4 .4 .

1 W. 0- 8 U'v.~ N-*4mmaeu'egN~7NN777 AvomA o444444444444444

T 9 '04.*Z"*2 2 ***0 9*fl., **,*IVA*s*'A*m4. m N444444.. - 444.c44.44..44.4 .. 4...

.4.4.4.4 ~ ~ ~ o ofj V1.64 :0 of -00 69 0 9 N N909NN NNNN-444' 44'''' ''

'4 IT~p41 144 14''14 N o NNNNNN 4.44 77 7'INNc444A ToTT '4 TT T77ff

A4 N-0 .40.14 N '4 4 -t.A a c", a*- A 4 -W .' 4, 4, n 40 A00~ A 04 .41 P-IA04 .4, lo '4D,0M

In A 900 M,-e a ~ n as -dO a'~ 44N99 coo~~N ~ 0000 0 '0 0 004

00=0N A f.4.4NN P.I IftMA4IA400 .4 44' Am elm A *, I 0: 1 MM& 00a, M50 0* 0

N~ &n044.... N MNNfNNNNNNNMNA44No41N ae#.. ..0e .. ..m.. g e. .. . ge .

gg0 g Ng Nlo gog le o1 08 o2 a1 go g gg

1111 mcSN.44 1144N I N 04'#4 N44.. 0. 0. i t i0. 10.0000

~~~,Q. ~ ~ ~ P cNv 4 0 ~ co * e N o 4ow c . 0,N N'4. . co4 4 4 4' ' ' I ' '4 4 ' ' '6"4~0 0 # 1 0 6 .00'0ý41 0 too: 99 9 0.9 0:1.990$ . .0190.99 o

w N .4.4InIAM AIIt 1 4*'44'44 L . 4.dItMA qN N4. 04)1 4A 4 A -c40 N N N N..4l

. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ a 0e-g --4NI'0N.I.0~PN-o-'.op444 '444.N t. c44 .4

26

0~~0 00091 a~-AgN a 0*0ufId *S

arn m!4 .. m .00 303 00S000000.4a

3 888388888 ga aa 0-o000a q

1-40 440 N 0#.61011 we* UO.4N AJPIA ga -d-dk N ..560-eNNN~O66 ~e fgi *5ei.4 t. M 6N' .4

J, .et .ee4j 44 jA.6e. Me. C.. CIN CCO -d C4

In g In.. l*5 d*I *U@ W02e~N ~ 09990001-191 00 000 N m mm""c -~2288888

alk 20 A ml~~ -4 A A N 40 2g4 MdE P P. NaM . N 4M ,

IC . . 4 C e. gem emaeeeIn I.m.e m a e*4 ## 1111IN ?AI . lm..eeIe I# of

0 13. 1.CZ 0 * 0 0 0 0. 0. 0 Me 9 aC~ w~ wrr. ',.rANN

Moo -d WI14. a CO I 1.38 8' jee~~e ee eeee~eeeem e0ee0 m Go a m0ee~,,

No 0 a gi,1 igggi ggg,, ggggggig

W% W Mq * ~ % NI M P A -M.e~~~g..... ~~~~;4 eN. gee. ee1.. e.,m e... M mm..

't 1 A

j~~ 0N~~~~~SA 104 W 4.16#4fI$ 1f-

27

gee ac.,. e0. ccc ge eg gcc coo 0cc000

00~oaoccs oss ooaoco Cooco 0000 oca

AA NogOigIF i61' 0 4A A g 44 ew4o.4vs S ' o oA

C e~~e~~c.lg~e geJ

m 4 4 4 l

S P4 9 9 9 'A S Pl A S A 8 9 A A V 9 9 m s 3 1 3 .10, V 14Q10"M 1 22sI s

14. "41 11. 1.I ...... .A ,A . n 1,1 W, I li In.AI *S ~ 0 Ic u 009 e . . . I 16 6

NNN4 AM AM944 494494 Allt TtMtTfff- ttftftj ff~lIrT.

(Y.0e .4 4 li. ý A044N99I994~.. 4A 7 11u11~9V I- Ie A lAI 9A 0

.0eC.Nw N P046Os~"NM 00mP1

ccc . Wcg dcc ScM.. gte W g4 g A~... in. e

28

-4,1 I ý nm 4'ogW , N *.4 N~ ý4- -- N U-d 0 9 * a4 a N 02 4.4 44.42003A., I . I #0, "4,1 10 4

~1. If ;4:3 -* .4Ns*..d4 NINN9mmOmm Vl# #0@0~0~0#40M.P . . . .. V:* 9~ 9 . . . . 4!0!* *

.4 fm N NNO040. 0p.p47M 4.~O99 AMO0.. MM499.49 AT A fl"A . ..

401,~ m 9p.~e p r m9 Nm N~m N N @O me 0 aO N 009.9999.. .4. -6 9 111, A

11 01 1 l. 110.1 11 0 9i 0N * m mm 4 4i-e ~ f~9l.0p10.. 1 s..e.....u0a..0000011.19

.9.o ,

09t o4.ao oo 00 0 00*6o oo0V 68090 40 0 60.0008 loao ooooo $6e8e.099 @9 9@ 99 99 99 9 19 9 :9 9C 999 PN wl snA -

00

~ ~8~o Maca oao 88 88888a 00 00 1acamo88886 1 0 1 0 1 $g 9 1*00 6819 40104 Ol e* 49 010, too$ of 40

g o,.~

9' ,4 oM

^1 N 1 1 ^ NN M 4

.4-Wt NNNN O tOe4N mmm mm m 4 4444444

29)

10 '3239 0 * 0 02 a 20

cc a~c ~$ nin oe 004

*14*0

I*e c v ~~ o. of 0 # 60 000 0 # 060 of0 6 00 oo#94014o4"o l 199 o o 6

a. we... a.. jeee~ *,e.e *eee ee ... eeC. ajjajjajaJ ;1 ta ;J 8J0

10.N M1loums3, 3VM PU Pleats 1' Onu Ma~ss 1838I3SP80U1S18sc

h Ill. ** I mp N am -*W 49 .C *40 *

-NL% 00-4 0Q00 co 00 02 0 0 a04 002 00000 .11 iii i iii000l T00 00 02i

k cc ee , *~ee .* * **e Og Ce . goo C , @ C C * S * *

4r .M N01 NW 04. 4 -.

t- !* 0 ,1 1 1.

00- . 9 . %NC40aUl . i `ý 1 1..ý V .. ,, .

0 N 0*N w .4 M It M 00y04 A d aP-ont, MIVN N-1-4-W-WIA

- Ce SC .. , . eee~g ,. ec**eg~eg* .g~CC S~e cc..MW

I

A ,04-d 0ý a P*.4 0* a .0 4*.me@N*p0•• .1 4•.4.4o~ooooo• 00 ao oo ooooeooe,,.0I- S I* . .G S# . ... . .. .s, 4,4. g. g I*a

g o,, oe,*loeee, OOgIggg pg TIl~llglg g~

NN r2Pl.. I 30833

000ca a 0 O0

ae goes 0 0 0 83

300600000 ooeeooo e000000Q e0 3333330 00 QQ0 8888081 05 0* 0 00 00 9 0 0 0 0 ,01 0,eg . . ca.s. . ag e . . . ~ . . . e e ~ ~ ~

o+ o • N40°ov•e+mN.4C+

.e ,....,.g . ,s... eg.. ge.. . .gg.......e4e+g..+ ei I I 'o p.0 A ft

04

, d l l l -d14 11 0 1 0 09 0,1 l

e ---ete g oe.....,.c... ge * . ,e ... e.,, .s c .......

~~'U4d*in e Me-c..... ýf NN, Ng N NNNc. N g..

1 4g ,4 1ece . e .11. Neici ii ge . ... .eee . e e e e .e.. e.0 c.. I

4+

,of

1 .. .. 4..d0 000000000 @@ 0 0 O 0 O 000 O 00

* 0 m

N m M m m 4#e

- ~ *r~l.1.1

31

.. ..... .0o.... . . . . .. .

....... 109940096000$*iol 099900999909-11 see"01 @09

I4 I 1? 1 7 TNTTTTTTT q"0 TTTTTT It It ftIt ItTift l-if rsea e " let tg q% usts ;IP.asqlq aAt-Isvs

....4.4...49* P-4% w5 W%*44 -1 N4 A. .4 4 1.4 F_ on. Ivt4 ,q N .0 .4 .0 - *.4 0 A 14 fq N

3338.44..4..

i 388 888338833

* 4..Ue-'---l. .. 4Is. 'll Jl uJilii J lt# Eq qIlt.4..4.t. thilEq I.444 P

0MI:.4ti-#.•0040, --o --4

" ----.. .4. . 4O,,@,@0 -, a00000,

~ IW 00Eq. .00

Co0I0.4. Mi iMA.MiFi4d444 44 44. 99099990 am99999 00 0009o a o 99 9 9 9 9 9 0 0 9 9 9 00

~ Vt iT t ti;iTttv VT Imm 0E .4 -d .4 w

N4.q4.iqq~91qqqqN NN44441~fN N ho4? f"Eqto A f" q4"q.-A.gg

OQ44Mi0M : a lmOý@~ @@ 33 A:ton, 4 1 3 0 0 0

609 09 96 .. .. .. .m e ... 4. .. .. .9,.,..,99 09

,.90, 4.41 .l? , a , N9. AM A 4 4 Z ?. ?i .h . I•A "•A AA -, ,,,,4,

liia t- 0. 000 0 0 44.4..4..4.. - 444.44.. .4.N4M4#4In.a.P4.4 oo.4.4.449999 996 9990 996 9999 990 9699 099 9996 991 1 on

.1 - 194981 to **

f*a f 'a 141 14 fy I" Af" A A A I A As a A9 11 f" M g AAA AA "A

li~in1 0 0000 a 0 a* 000003000 0 0 -- 00 00 11 00 '0i0ll * 0 .0

090 1

60 0609@.A0N.4 NN .

Itso # 9 a 09m 0. 0@o*@Pop-.-

in00f.00 f0 .40 e0,CN -4m 0 0 ft 4AwkN.N A6 ~ "-4o A 0 *.* am . 0** Am4.9 0909 N NN N 4 N N W In~ aF @1 0~4 . 4 4 1- .~SI A 99N N- 4 0

Cc 001,00a a0 04a'a4 aWN 1@.oNg IO0 aNN.a0 0 4000 a 0@ 00 0 0 0

-3 00ý- '3N rzM , V g ý t00 0 0 0 000 00000000. n n " 0 10 o f. Co. . ./ .. ... cc

4 -

WMO-WNM*6M4F- QN0- 050#

~60N OA~e p~d. 0AN NN N %ICNON 00 0

33

4.. . .499., .... ....... N •d~d~. . .o o.* . . .... ,.

Sw g =4 AdNNdd U80 "=454f999~9 -A 9 A ~ A% 9 In9 in

S~~~~~ 0 . 6 aa I 9o a a 9.9aa . a . .0 00m 9 m a C

e o e o e t~ ~o Ioo e e e e t e Ie o e e e IeIe foI IeI

~~~~~~ 99V 1~9~999

aooee eee ooece O 0II t O l o I

'00, w m .

Caol -Pa . 'D .a a .0 N 0 . a a C . * o. AD I . y 0% .

?T•~~ * ,,,T~fTTT * ,, In ,,. a .0 doT

9S 9

N4 N f N N N f~fCNO -N N N N .I9N0E 44

I I I I 1p I I I toi •

41

-4 N N N 6d 94 -d S .aa.a 9 9 0 a a gas9 p.99,999 1191i ~.g- . . . N 9.. s@9 09 9 o $* . i

9IIII g x '22m st mm

9UN CON in in90 ~ ~ .94 N 4O. N.NO of-.9 a au . 99 99 9 9a * 999 5 9 #,9 A.

-4IAO.-ifq N$ Nt N0 9-Y--9 (v0 N N PY A~ 04 . d Z

34

A l l :4 14. d V -, v w ' NA N ,, 4* CO. NM 03' W e tfV W N ' 4 - 4N ' 4 4 4 2 0 0 '00 0

.e ~ ~ 11 1 1 oi.. .l ge e * * e e ~ g ,,. ge g~ g ~ ~ . .

0IA40. ~ SM g;!:;~ Ae* F40.000.. 6

Jg eeig 0e N g gi N Ne00 a Ne i IV

't 'A 00N.00. 4oaAA..~e . g'e eOkaee "Ae... geg g gg0N.. gQeegWNq- CAI

.4 ~ ~ O In.40- 01-W% N .4 6'We We4NN.

NNI NN Ng NNNN NNNMN N NN

iI~ ~ ~~*'a -,C LI NO-O M 0 4"Ne A* 4.I a*We40 MM' A We ON .4 OVWe MO ON 014 I".4 ' p eg Nj I. NZ'? ~ eUI

W%-*401" -40-4AN6' *Ae4'-AWNN.9. 0 000000 cool if.. oegg~~~~~~~~~~ S* 9~g~ e 1g eg g e g1gg1g.e e~0. .0. . 0 1. 0. . 90. 0 i ili i i i ot 0 . . 1 . . 0

;a 474#f" 4643-7mln 9NNNNNN NN NNN-1V -W .4-3- 'N~ No NNAN 010 CIANSN

W% W1 '-ý .46 NA 0 .0.44 -.0 IA 0e Nc N0 in' in 41 I*-N d Z * We .4 e I 0 4-6 AW 00 IA N.J in

i1.%S 0 *0.0-AO rIa, 0.4OP. N *n-t -w m -r U, '. P.0' m4.4in00 0 -4N Mt k* t00 0 0 100

, A F; 0 .NNN NN NM M NN" m44.1 4 el I t .I t e .1PIA inI

35

F. o p- 0In w 422022222042 :2 3 02 02 2 0 00 o

O.~4 ~ ' NN ' I'm N ¶NN N1 N4 N4 N 1. N 4NN¶N N N v -4 N INNI'9 N N N N N 'n

#4* .** 94 slow 09 0 of4 9444 9tto * * too 94 6 * * *o ff$4 Vat * 9 44 ill 441

0.~~~4¶j 0. 1611.5 lol 11 1 11 1 11 1 I 0 193ffAS &a 1# 1 a I. i aI~a *

'a : , 0 * -t Fit -t - -P -t

2 In 4 0' 2 2 A 0 0' 4 .- o-do 4.4 N N' N4 N' 4 I A, -Y, IAY0 .0.4, J, J, a*-=9 0. J, .4 u u~ a 'a '

1 0 2 0 2 0 9. 4, ,9.~ N******N*.4 4 N* 44 4N94 94 4 4 N N N4%N

IA4 N'1 1 1 TAI1 A I 11"A I 4Pt -1i TA0 T.f $~ $9U1% 0%%9~ T ~ I4

j U, in T I

MQ, 004 0 WO N A0%4-4 t-9D 40 'A 01"t- 14-46%aP IA 94 ' = N- N00 I*t N IA6NNOl'99 -

04 44M4 1 0 !6' A

1".14.0 13994*.I49=N" I"10.13

Inm01 -11 't # A0* t ' %43.W% LM tA V% ke 6%l' InAIIAinAI W% WAA% A4% LA 4 %qAII 4ý.

A~~9 o UN <0 a4- ep. r. "3 4 0I4 N n2m 4 w4v4a.

444o W4U "AA4 44454 1449 9 9 4 4 4 4 0 49 4 4 4 44 499z.4 j 0

ir ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ .49=9=90weF-w 10-N-14W -, ,ý P P

36

U% -0 1 0 '4 'N N4 "1 1 `4 'N N4 N N NNNN N '4 N N I

NNM.f "Ac AMl "A AM ucM-A" "Mf# MA t4

* g gg g *,i gs sg~s~ mg I S II I do,af -p.A A AA VN v NNNcSe-0~,A. -. g-&* 000# VN - N- ve..ucVn*A

uo zn 04 -m0: 0 ~f-a g.*~~~~~~~~~~~ ee0~g 6 0eg g e 1,~e c 0.. . . ee 0~.. 1~

*-00 0 3* 0' .)OAe*cpoo N'.-4-of-a

2 0 0 2 2 2 2b4 . . N N N NeT iT-ceTc cc c cc c e'cc

06220In2I

e. g.....o A40-* 4inI -ec d *eq III~ Al e6A.....P e.g. N.. , 15. -A.Adl..

In - 0: A V-4 - .40 A .4 t - 0' n M1- -400 t 0

0 2 h d14 -a-W 0 4 In ' In P.- . 11*NI-'2 Ce ccN - .4-40O02 .4 d 4 4.4-4 -4-W-4 4 W 4 4 - - 00.

.4 4 d -4 4 -d.4 4 , - 4 4 W1-1.4 -4 -1 4 . .4.4 NN -4 f4 NN N %1N N.N4yl

.. kA .#., t -4 .4 *In -W g. mg ~ 0 ag ot 02 02 W %0 2 In A 2% 2o ao 2 a M,20 2en 2

ggae-L -I.eg g0 g gagg we 1-g. geg gg* 03e~. ggge gggZ,

t- p-. vA -d -4 -4 14 .4 S. A *4~ - .4 -4 .4444 .4 -4. 04 2004 02 22 22 24 .4 .2 2

h~ý .4 -0 N N N4 N N N N N4 N N Ni N N NNNN ' N

I, N Z j jfp P I Ac m I 0 e 4%4t. 5 4, UN It'20 & 0-e N0 P.N0 0vf P n 10 F4 0c-( ý~m l n fc 1ý

_4 _ ýrCP ' 444 0' l 304-- 0 W~f i 07- e .In r11..'A N - 4

4 In C 11(0 a 0 N 'AN-P I NN, I, Wc 111 cc ac cccccc.Pj 0~' -41 .4r' 0 4 -4- IS-

3t

- � � � 200203 - I020022222720222030 00020000220002020000-2000222

20022�22222222220002202 222020.d,. ggggtgg.� g g.e * g.g* ale...... .. . . g*e*g*g*. getgag*g

- �eA*-4 4�'AlU0 � �=g. gag,. a e.g..... g.e...... gag. * g.e...... get...... t. . g

4�OI� � � � 02000 � 2 02202220LU -

***t***** * CCCeSCOC * Ca** *6aS�@*t I j* � �

gtgtttggg es. a. g.e..... g.t.e.,., gee. egg.... .e g e Ste Og

05 0 0 02 20 0 0 2 0 0 0 0 0 0 0 0 0 20 200 000 0 002200020000 2220000025

.t *e*t *t tag.,..., @OgSO ggg a S *�t ee:..ee. ee a gte.. e.g...

p7000050 2050 02252 20 §2502020000'20020500500S

eega*aae.g99e.teega e*,ggOgegagta.aggeegg eteegeg.

0 0-000

§.4N

IU.11.a � ��NN.4.4000002 520500200200000- � 5005000 0500� 20230

.e .eaggegt e.g. tea.... a.e.g e.g...,, ee ee.. a. Sues

� I � �� .d -':**: - .4.4.4.4.4

�

* .� �N0�'JOI*6NNN..4.4.4�a-a.402220�0000.220000020o0ooo.2o

�O�m�RO22.4.-tN N � '66'6'� �6.� �002220200220-200220000200000200 22030022000002030

2-02 00.20.- - .4.4.4'�.44.4-4.e.gaeeee�,.e..e..teeee.eegeeae�e0ge. g.e...... at...,

-

� ceegge gee gage...... gage,..... gee e.g..... gee., tee.

2 .3 3f :1 -j .I N -j' 3 -j 44 3 3 3 2 2 3 2 2 2 3 2 3 3 3 2 2293

4 4 ~ O 4 5,.4-.4- -4-44~4- . .4-4 .4 . .4 .4 .4 - .4. .4 144--- --. 449 4 .

N~ ?.

r- 41 N 44 0 'n N N in N 4 N N 3 P- A A44444**'~ .4 N N -444* a' 4l 44 44 0 .3 a a

2332333232333303033333338-3 32933.8 oil I Ras

is i I

4.4 **, ,.4 ,., .4 4 .4 9 4 4 4,p 4,- -4 O -4.4.4 -4 .4 w- -4 -4 4 49994 4 P 4 9

44L II

22222 23202 2020 23222"In2 T 'I

P- A 1 3V200 0

29923 3 0 3 02 02 03 z z222232 0 3 32

I ~ ~ ~ ~ ~ ' P. A3300 A3 -32 232.09223 U' In33332 b9 P.32

-4~,I a, , a ,~ 4 44"4R4$ 4 P- 11,1414 n 0 4 4 P.01-1 P-3 O'4 P. W1~N%,"-U4u0 -'4.m 414 a

11I 41-1N,-4. .41 N 14% -4444~..4 f4 I .- wI 4 %I 0NNN -W 4 - 1 IT33 -'

Ar let*r~ - 00 'J" Is r v -NIt 0 -1N L or. ct0'0- le 4- f.~ 0, CY In4 10 1- W4

39

4 N~-2 ~2.0 In . 4 m0 A 7) * '1 0 n 4N- 4-42222222 )22~22222 22 )22

10n Al 40 g

-q 'A~llf AA in 41 In in f%014 A~I. I IJ IA I I'- N q T 1^11o n P

ft *4 *4 'y -4 -4. -- 4P A1 1 tN 0 . PP n N mF.W 4 Y-...I

.~ 22 22 2 00 2 032222 2 2 2 2 2 22 1, 2b m 2 2 2 2 2 1 32 22 2 22 1 !: 0 2

22 2 2 2222 2 2 2222 2 222 2 2 2) 1, 1z 21 z 2 2 j t 2 5 a22 22220. 0. . . . . . . . . .2222 222 222

12 2 2222 a, J j 13, Z, a j J, 4 4 3 A -3 .322 A I

-d 66III 6 66 6 *6 66 6 III6 66 6 6 6 66 6 6 6 a*44"6 l o f

3'; 5*a a 1 3 3 3 8 1 , 8

0 ~ ~ ~ 2 11 N2 ID 2-M2f ~-.0 0- 1 0100 2 12 22 02 ID M 22 -6 4 -0 2 -2 -2 2 a 4 0 2w 22 .4 24 22 2

AlN 11 "1 A, 414 1, P,- -1 P, P114In ' 46 4 P6 4 4 6 1 N 'A 6 6 6 A h 6 1* 6 In t. 6 6466 IM N -4 64 N N # N 0 6t f) 6

13 4 4 ~ N 4 .'- .P.2 22 -A2 2 )2 ) 2 2 2I -A 11M11 1o21 1*, 1 121W 1 "10 n I I"IP. 1 11 2,-1N22 2 2 2 N2 2 2 IN22 2 22 2 222222-22wP222222 4w0 mA I 4-WMP.VIi1 1 4- . ,

~~2222 222210 z222 2 222 2n2) 2n222t522 22 n

V%444. 04 VI,`' PU IM r MW IU~~l.IM t T I'I e)fl T4' F.

44 Cgg afI II P. cc g(1 g ItA t iA4P 1+ 111 1111I I

al ' 4 A -I N0, -, - 0 ~ ~. 4 N - 01 tt N N-4 '4 4 -4 '7 .m '4 11 7 N N ~-4 - - 0 P, 0 1, 4 I 't "'I A 4

40

9 9 .. .0 I . .9 . . . I

'-N -tIn I r- n A P02-4N 4u In ' - n.flf4A 10Jl ýO10 0 A* f 0 10f40

IN ginnIN nomw4)3*~~ In a Q - nM'P %0~ C ~ CU4

o9) ;I 19)~ 99 4 9 9 9 '39 9 - 9399~ 991 990 : 3 11n '

0Z

S sý

L&trto 53 ol 199* 991 94 99 9 94 9 9 4 9 9 9 99 9 99 9 941940

H IT W020 2-,110200020224232GA2.PV20n20NN 20024 'Z 0 22 'D 2 '20 ý j0 3 023221 Z 2220

l.it2.Y. CitJ-,1tJ"O 4A 4 -il N N-, .4-4.4.4 -404002222000-i0202ý-ii.2'2'2)30'22

24+)4n ~ O -J A ft -4f "i C1 NP T1 C' N '3 0 4.r p- 91 -4 (A gUsA ' Ad40ý i AI. N9 .41 U A m A fl'A'I . ~in A 4

999994'-j n999 9 n*~ 9 9 9 9 n,99 4 9 9 91 91

[2 o

It 3 il 1111 I l. gi .gg .g g gi. .il .i gil . .

n .i. n n p; tur ri mtL vta I, tc l rU'4An . Si I P. APiý - t A P .f O M I-

iz z s:Nm 4, j-& uP-,N A' t I *~ J .'-r. , .'- -T l ýI'~~~~~99Q~~~' "- 99 9 94(I.99 99 9 99 9 99 9 9 99 9 99 9 9N9

2~- i2 - --4 -4 '1 q-I.'I.

41

~ ~ ~ A ~ '*~ 4 - P ~ .3 t - 3~ 1~ 1 3 3 3 1 J- ~4-- 2 2 1 2 j 1 3N 'd ..j .4 w n n 0 I ) nJ3

I . . . . .. . . . . . .. .. .

V•. V '4 'AnAAnnn n n nt n IM I n , I ' 00' -P ý* *.*.* . . ...... ,. 444. ..

P In 1, ,, In 'M F- ilpl.. . . .. . . .

5 .... **. . . .. . 6• , 0.,•, ,46,. , 3,,

2 ~ ~ ~ ~ ~ 3 23 2o 22 2 z 2a 222222222222

2 22 2 2 -2 23 2

NI

it It -,. 1 , , o , ,. ,; ., . , , ,

f) 1M. In4I nI A' n o mDnA',P. F .'3 ~ ~ ~ 2 '2-V M 1m' N n 0 4 "Z1!,A 7 ,1 1 F. )p .. - %4 1 A -I,% 2 d 2 3~ PI. I'.5 5, P. -MKP lr6 I' .P- ". t 1 .)C ' nI-I

ZNg. 4 4,o4.7 .uN 4' In M'. r' Zo P. It,

If , I4MMiIII 1It Mm ni n4 4u4A44 4 *r....P.- *4 I, I,4P64 4I.4 4 t-4t.4P-4V 404u a

gýg ig .g ii gg i A.g g. i - . g; gg. i It, "'.i gg,

~~~~W It i nO N 1~- 9 4.2 l A .y -1 -t)-4 -

2222 2222 2222 2222 2222 22,2 222D2~~~~~~ 2j -j N 2y V n t '22-

u2 22222

42

inr a0 OMI ? 7 rr -'T2 2 'z2 .222 1 0

1.0

'Y -4 A- -4 -t.* .j4 Tfl In I inn I Inj% % 4 al 1 a 0 atn9a

-1 .4. -W44 2'3 -Ni

202 220122 52 222 22 22'a22 22 22 Z242.222'22222.2j'. ''3'

N4 44 Mr 4v 4 * 4* N 4 A 14 444444.4 ' -' 1 4 .4 -4 -W i *j :j .

0 ' K a-0 RJ 1 -O %2 0 2'3 22 2 20 2 2 -4-W 4 W'4 4 2 z -2-4-42 4 4 . -4 * zz - .4 -

11 P; 4M 14 -4 -- N--A-4 2 2 O P0 2 2 2 0 0 2 LAn220P20 f 7ýI

P--4 N 444 944 44 A 4 . .4

1.,.3 a.3

'22 .2.2.2 .0.2. .. - 44 .4.4 44.. 4 . . *.4. . .

11 r f, ** 9* 9* .2 49 44 4 A4 44 9 I4 4 4 4 4 44p '4Vfg *P*-4-P4P tN I a .Im iK~~~~~~~~~~ I~~tt.r ' ' 4 ' I44 IJ~-~4O t.-

m 0 13 P.- In, 3 0 '4 N 2 fl C.l4' ' * ' 4'D 1, - 4~.4 I14.+'

9449o4l 'A llm.4d 444g1.-......

43

In v P I - - n r -P -P C O n W 0 C7'a-10 -7 i O a M p a-r ; -a p .u"3 j = 3 0 %3 3 3 1

,P. t 0 4D n' Q9 p 2 2 2 3 2- ~ ~ ~ C '3223 I22 32 2n 33

W P-2 6%t'. JN- *. -- a 40,. A 9

~2222 24242222 22"04222222 M O 2O-12 2 2 2 2 2 2 22 2 2 2 ~ 2 ' 2 ' # 000a0 601 91

0.o m, 222 1*l m . f2 f fup2 I N 12 LAJ3 2. . J I e2 f22(p q 2 g3 2 z 22 2 2 2 2

v n -n.m†m†† † † † †m†† † † † † † † † † † † † † † † ††,9m9999991*999.2 399

A A -IN A O0 1% 04t t t & t tt, - 3M22M 0 2 % M2In f. P

22222222227~~- in2~ 27 2 i 221 "M2 2 2 2 2 22 2eo;22 22 I'-2 22 2 2 22 2 0 V22 72I)2

0.* ,* *l w *! w* Q V1 N N O* 4 y * ******* * * * *

~~~~~~~~~~~~~~~~~~1 n99 9 9 9 9 9 9 9 9 9 9 ~ 9 9 9 9 9 9 9 9 9 9

3732322o223 3 5 '3272 2 3 '222 222 no2 '3 2) 3 3 2 ,03 '5 1.5 1n I 21,,.. 1

2 0 2 3 I .3 I )11 . 51 .

a.~~~~ ...9.~2 .i2 .3. ~ 3 .22 . .. .. ..

I, m P.9. f".U?2 Ij 'f Q ~ 2 2 2A2 2 2 2.2A; C I W -4U 3 --09 , r Z' c -ý rV L,12P p 1-a 4 .% I ) t

2201 1 -1 1'. 6r ^1 W 'IOO 0 M ~ ~ . . .49 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ I r 9ý 9 999 9 99999 999 9 99 99 1 99 999

na t t t t t -I ,A r a o vi -il ri P, a o -4 P. q 4 t a -i 3-I -- N- 1N jI n,

I

45

Acknowledgments

The author would like to acknowledga th helpful review provided by R.W. Penn,

1R. Penndorf, and F. Volz. Appreciation is xteided also to H. Wexler and

D. Chang for their discussions pertaining to meteorological aspects and to

R. Hoffman and J. LPuseo for their particip tion with computer programming.

I.Ii.

I

47

References

,Baum, W.A. and Dunkelman, L. (1955) Horizontal attenuation of ultraviolet lightby the lower atmosphere, J, Opt. Soo, Am. 456 188.

Bigg, E.K. (1964) Atmospheric stratification revealed by twilight sca.ttering,Tellus. 1677-83.

Bullrich, K. (1964) Scattered radiation in the atmosphere and the natural aerosol,from Adv. in Geooh sics. 10: 101-257, H.E. Landsberg and J.E. Mieghem,Editors, Academic Press,"FY.

Clemesha, B.R., Kent, 0.S., and Wright, R.W. '(1967) A laser radar for atmos-pheric studies, J, Appl. Meteorol, 6.386-395.

Collie, R.T.H. and Ligda, M.G.H. (1066) Note on Lidar observations of particu-late matter in the stratosphere, J. Atmos. Sci. 2 3:255-257.

Crosby, P. and Koerber, 13.W. (1962) Scattering of light in the lower atmosphere,J. Opt. Soo. Am. 53:358-361.

Curoio, J.A. and Durbin, K.A. (1959) Atmoseheric Transmission in the Visible'Region NRL Rpt 5368, U.S. Naval liesearoh Laboratory, Washington, D.C.

Curclo, J.S., Kneetriok, G.L., and Coaden, T.!1. (1961) Atmospheric ScatteringIn the Visible and Infrared. NHL Rpt 5567, U.S. Naval Research Laboratory,Washington, D.C.

Driving, A.Y. (1966) IZV. Atmospheric and oceanic physics, Vol. 2, No. 10,pp. 1046-1054 (U.D.C. 551.593.5:629.195).

Dunkelman, L. (1,952) lIorizontal Attenuation of Ultraviolet and Visible Light b.,the ower Atmosphere, NRL lipt No. 4031, U.S. Naval Research Iaboratory,Wash~ington, D.C.

Edldn, B. (1953) The dispersion of standard air, .,J. Opt. Soc, A\m. 43.330.Elterman, L. (1964) Atmospheric Attenuation Model, 1964, in the Ultraviolet,

Visible, and Infrared Regions for Altitudes to 50 km, Report Ai'C•L-64-.740,AFCRL, Bedford, Mass.

48

Refegrences

Elterman, L. (1966a) Aerosol measurements in the troposphere and stratosphere,Appi. Opt. 5, 1769'.

Elterman, L. (1966b) An Atlas of Aerosol Attenuation and Extinction Profiles forthe Tro osphere aind Stratosphere Report AFCRtL-66-828, AFCRL, Bedford,Mass.

Fenn, R. W. (1964) Aerosol-Verteilungen und atmospharisc hes Streulicht, Bje.flagezur Physik der Atmosphare, 34(No. 2): 69.

Fenktistcv, K. P. (1965) Some results of optical observations from a Voskhodspacecraft, in-, G. A. Skuridin, et al., eds. Issledovanila komicheakogoprostranstva (Investigations of Cosmic Space). Moscow , Izd-vo "Nauka"',

Foitzik, L. ( 1965) The spectral extinction of the atmospheric aerosol by Mieparticles with different Gaussian distributions, Gerlands Beitrage zur Geophysik

73feft 3, 199,Friend, J. .. (1985) Propertiea of thre S71trao.heri AerosoL Isotopes, Inc.,

Report for contract D~A-49-i 6-Z0 ne Aomic Support Agency (U)2 N ov.

Grams, G. and Fiocco, 0. (1987) StratogpIheri'ý aerosol layer during 1964 find t965,J6. Geophys. Res... 72 13523-3542.

Gucker, F. T6 an asu, S. (19B3) Ri hfttangle Molecular Light Scattering fromGms iRtN.1Cotat 172-2).'.4-00, U._of Indiana.

June.,C~E. CagnnC.W., and Manson', J.E. (1061) Stratospheric aerosols,

Jung, C'E.(193) Ar CemitryandRadioactivity, Aaei rsNYKneoric, G L. Coden T.HiandCurcio, J, A. (19601) Atmoin heric Attenua-

tion Cefficients!.An the Visble and Infrared, N'RL Rpt 5648, U.S. Naval ResearchCET-o-&Fry, Wastington, D.Q,

Kondratiev, K. Ya. , Nicolsky, G.A. , Bsdinov, I. Ya.,- and Andree-v, S.D. (1067)Direct solar radiation uip to 30 kmn and stratificat ion of attenuation component.in the stratosphere, Appl. Opt.6 81197.

London, J. ., Ooyama K~ and Prabhakara, C.,02 e York U. Final Rpl,Contract AF'19(604;-5492, ABVCRL., Bedford, Mas..

Mateer, C. L., Dave, J. V., Dunkelman, L.., and lfvans, T). C. (1967) Evidence ofan Upoer Stratospheric ust a-er in aStli4 wlgtClrPootahReport X-6 13-67-533, Goddard Space FlightI Celiter, Orgenbelt, Maryland.

Meinel, A.B. and Meinel, M. F. (1964) Height of the glow stratum from the eruptionof Agung on Ball, Nature, 201:65'7-658,

Miller, D.I-,. (1967) Stratospheric attenuation in the near ultraviolet, Proc. Roy.Soc. (London) A301: 57.

Mossop, S.C. (1t964) Volcanic particles collected at an altitude of 20 kmn, Nature,203:824.

Nuwkirk, 0., Jr. and Eddy, J. A. (1964) L~ight scattoring by particles in the upperatmosphere, J1. Atmoes. Sot., 21,35-60.

49

References

Penndorf, R. (1854) The Vertical Distribution of Mie Particles in the Troposphere,Geophysics Research Paper No. 25, AFCRL, Bedford, Mass.

Penndorf, R. (1957) Tables of refractive index for standard air and the Rayleighscattering coefficient for the spectral region between 0.2 and 20.0 p and theirapplication to atmospheric optics, J. Opt. Soc. Am. 47: 176.

Rosen, J. (1968) Simultaneous dust and ozone soundings over North and CentralAmerica, J. Geophys. Res. 73:479.

Rozenberg, G.V., Ed. (1960) Prozhektornyi luch v atmosfere (Searchlight beamsin the atmosphere), by IU.S. Georgievsklii, et al., Moscow, lzd-vo AN SSSR.

Rozenberg, G.V. (1965) Sumerki, Moscow, Fizmatgiz, 1963 (Engi. transl.:Twilight, New York, Consultants Bureau).

Rozenberg, G.V. (1966) Paper presented at the International Conference on theInvestigation of Noctilucent Clouds, Tallin.

Sandomirskii, A.B., Al'tovskala, N.P. and Trifonava, 0.1. (1064) The seasonalvariation of brightness at heights up to 17.5 kin, Izvesttia AN SSSR, Ser. Geofiz.No. 7: 1121-1127.

Spankuch, D. (1967) Brightness measurements with a vertical searchlight beam forthe determination of the vertical turbidity stratification in the troposphere,Beitrage zur Physik der Atmosphare, 40, 1/2, 956/117.

Stergis, C.G. (1966) 4aleih Sgatterin in the Up er Atmosphere, ReportAFCRL, 66-267, AFURL, Bedford, Mass.

Vigroux, E. (1953) Contributions a l'etude experimentale de l'absorption de l'ozone,Ann, Phys. (Paris)8:709.

Volz, F.'E. (1965) Note on'the global variation of stratospheric turbidity since theeruption of Agung Volcano, Tellus 17.-513-515.

Volz, F.E. and Goody, R.M. (1962) The iltensity of the twilight and upper at-mospheric dust, J. Atmos, Sol. 19.835-426.

Volz, F. (1968)'Twilight and stratospheric dust before and after the Agung eruption,paper in preparation.

Waldram, J.M, (1945) Measurements of the photometric properties of the upperatmosphere, J. MVteorol. 71:319-338.

U.TS. Stkndard Atmosphere 1962, U.S. Govt. Printing Office, Washington 25, D.C.

' ' !

S-

UnclassifiedSecurity Classification

DOCUMENT CONTROL DATA - I&D(Se.uril cl dasslflcation of tille, body of abstruo and indeamne annoijoin must be enteed whom sAh .n'vmll !eport is classifled)

I. ORIGINATING ACTIVITY (Cofatho t ml~o) - |0. L REPORT SECURITy CLASSIFICATION

Air Force Cambridge Research Laboratories (CRO) UnclassifiedL. G. Hanscom Field 2 GROUPBedford, Massachusetts 01730

3. REPORT TITLE

UV, VISIBLE, AND IR ATTENUATION FOR ALTITUDES TO 50 KM, 1968

4, O"ScmipTivi NOTES (Type ofeporn and inclus.i da•tsezScientific. Interim.

S. AUTI4ORWS (First snme, W m iddleiIal. last now,)

Louis Elterman

S, REPORT OATE 79h TOTAL NO. OF PACKS 0 NcoPrEApril 1968 56 45go. CONTRACT OR GRANT NO. ,, . ORIGINATOR'1 REPORT NUNSEWIi )

4 J6 EROJACS, TASK. WORK UNIT NO$, 7670-04-01 M. ' AFCFtL-68-0153

a. 000 ELEMENT 6240539F! oh ob•. 0T JPoIRT js),(Ary oA.,,mube, Mts nuy b

A POD. sUILEMEMT 681000 ERP No. 285

67,' OwITRi,.TIom PTAY.MENT

1 - Distribution of this document Is unlimited. It, may be released to theClearinghouse, Department of Commerce, for sale to the general public.

III 1UPPLEMENTARY NOTES IS SPONSORING MILITARY AVTVITY

T H TEi Air Force Cambridge ResearchLaboratories (CRO)

L. G. Hansoom FieldBedford, Massachusetts 01730

t iII, AEIITRACI

\An atmospheric attenuation morel for the ultraviolet, visible, and infrared wasdeveloped in 1964, based on scattering (molecules and aerosols) and ozone absorp-tion. Since then more'measurements have been made and our knowledge of aerosol"attenuation has widened. These circumstances result in attenuation model changeswhich are relatively unimportant for most exploratory calculations. They can be sig-nifioant, however, for long slant-path high-altitude applications entailing large zenithangles, factors which characterize, for eyample, the measurement geometries ofrockets and satellites. Anoordingly, a revision of the 1004 Attenuation Model iswarranted.

In this paper the optical parameters are computed spectrally and with altitude asfollows: (1) pure air attenuation parameters are determined by utilizing Rayleighscattering cross sections with molecular number densities from the standard atmos-phere; (2) ozone absorption parameters are derived based on VigrouxIs coefficientsapplied to a representative atmospheric ozone distribution; (3) seven sets of aerosolmeasurements are compared and a profile of aerosol attenuation coefficients vsaltitude is developed. Attenuation coefficients and optical thickness due to molecular,aerosol, and ozone attenuation are computed and tabulated individually so that theinfluence of each can be compared. The newly derived tabulations permit variousexploratory calculations, including horizontal, vertical, and slant-path transmissionat kilometer intervals to an altitude of 50 kin, individually for each attenuating com-ponent or for overall atmospheric extinction (molecular + ozone - aerosol),

DONOV I1Unclavsified

Security Cl-asification

I

UnclassifiedSecurity Classific•tion

, K RLINK A LINK a IINK CKEY WOROS ___

ROLE WYr ROL WY ROLE W?

UV atmospheric transmissionVisible atmospheric transmissionIR atmospheric transmissionAerosol atmospheric attenuationTransmission in troposphere and stratosphereAerosol attenuation in troposphere

and stratosphereModel atmosphereLight scattering

T 1nelassifik-td

Sr - Q i

I t1 aH' l