An Army Illumination Model

(AAIM)

by Richard C. Shirkey

ARL-TR-4645 November 2008

Approved for public release; distribution is unlimited.
 

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Army Research Laboratory

White Sands Missile Range, NM 88002-5501

ARL-TR-4645 November 2008

An Army Illumination Model

(AAIM)

Richard C. Shirkey

Computational and Information Sciences Directorate, ARL

Approved for public release; distribution is unlimited. 
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An Army Illumination Model (AAIM)

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6. AUTHOR(S)

Richard C. Shirkey

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U.S. Army Research Laboratory

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13. SUPPLEMENTARY NOTES

14. ABSTRACT

An Army Illumination Model (AAIM), for use with Night Vision Goggles, has updated the Light Urban Model Effects (LUME) with new 

algorithms for cloud reflection; it also has been augmented with a population database for model input. In addition to providing illumination 

levels for cities, the model now includes values for lunar illumination under clear or (partially) cloudy skies at ground level. AAIM may be 

used in tactical decision aids and wargames for an observer at ground level, allowing for more accurate prediction of target acquisition ranges 

and increased realism in simulations. The original tenets of the initial model have been maintained – prediction of broadband brightness as a 

function of population and distance (>10 km) from city center under clear and overcast conditions. A technical overview of the model, along 

with future improvements, is presented.

15. SUBJECT TERMS

urban illumination, brightness distance relationship

16. SECURITY CLASSIFICATION OF:

17. LIMITATION

OF

 ABSTRACT

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40

19a. NAME OF RESPONSIBLE PERSON

Richard C. Shirkey

a. REPORT

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b. ABSTRACT

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c. THIS PAGE

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(575) 678-5470

Standard Form 298 (Rev. 8/98)

Prescribed by ANSI Std. Z39.18
iii

Contents

List of Figures v

List of Tables v

Acknowledgments vi

Summary vii

1. Background 1

1.1 Garstang’s Model ............................................................................................................1

1.2 AAIM ..............................................................................................................................1

2. Clear Skies: LUME Review 2

2.1 Estimation of Constants Used in Brightness-Distance Relationship...............................3

2.2 Zenith-Angle Effects.......................................................................................................3

2.3 Azimuth-Angle Effects....................................................................................................5

3. Population and Location Database 6

4. Lunar Illumination under Clear and Cloudy Skies 6

5. Illumination Due to City Lights Under Cloudy Skies 7

6. Spectral Composition of the Broadband Brightness 8

6.1 City Light Types and their Spectral Composition...........................................................8

6.2 Radiant Energy Determination......................................................................................11

6.3 Convert Brightness to Radiance Units ..........................................................................11

7. Validation 11

7.1 Clear Atmosphere..........................................................................................................11

7.2 Cloudy Atmosphere.......................................................................................................13

8. Program Usage 14
iv

9. Conclusion 16

10. Future Work 17

11. References 18

Appendix A. Population of Select Worldwide Cities (Metropolitan areas used when 

 available.) 21

Acronyms and Abbreviations 29

Distribution List 31
v

List of Figures

Figure 1. Geometry used in AAIM. ................................................................................................4

Figure 2. Geometry used for cloud cases........................................................................................8

Figure 3. Spectra of light sources in table 2..................................................................................10

Figure 4. Sky brightness due to Denver as a function of zenith angle at a distance of 40 km. ....12

Figure 5. Sky brightness due to Denver as a function of distance for a zenith angle of zero.......13

List of Tables

Table 1. Estimates of the constant of proportionality, A, and the corresponding 

population, P. .............................................................................................................................4

Table 2. Breakdown of Street and flood lights in El Paso, TX and Las Cruces, NM in 2007. ......9

Table 3. Program inputs and their default values (from (15)). .....................................................14

Table 4. Albedos of various surfaces............................................................................................15

Table 5. Cloud base heights for cloud types in AAIM. ................................................................16
vi

Acknowledgments

The author would like to recognize Dr. M.E. Cianciolo, of The Analytic Sciences Corporation, 

and Melanie Gouveia, of Northrop Grumman for much of the initial formulation used in the 

construction of this model.
vii

Summary

An Army Illumination Model (AAIM) has been developed that estimates city brightness as a 

function of distance, look-angle, city population, and cloud cover for an observer at ground level. 

The model, which builds on the Light Urban Model Effects (LUME), has been modified to 

include city light reflection off of clouds and determination of lunar illumination passing through 

a clear or cloudy atmosphere. A database of select worldwide cities is supplied for ease of 

population determination. The model has been verified by comparison with external models and 

with measured spectral values.
viii

INTENTIONALLY LEFT BLANK.
1

1. Background

Calculating the illumination from distant city lights requires knowledge of the illumination 

source intensity and spectra, and solving complex radiative transfer calculations to include

multiple scattering by aerosols and molecular absorption in a non-homogeneous atmosphere. 

Currently a number of models exist for predicting urban illumination as a function of distance 

from urban centers at visual wavelengths or portions thereof. Since many of these models (1–9)

were constructed primarily by members of the astronomical community to define the effects of 

light pollution on observatories and observation sites; they do not include the effects of clouds or 

cloud cover, although significant progress has been made in this area recently (10, 11).

The preeminent model by Garstang (6, 7) uses radiative transfer approximations including first 

and second order Rayleigh and aerosol scattering, effects of ground albedo, curvature of the 

earth’s surface, and the areal distribution of the light source to calculate the sky light intensity. 

Since Garstang’s model is widely mentioned in the literature and is the most comprehensive of 

the semi-analytical models, it is the underlying basis for An Army Illumination Model (AAIM). 

A brief synopsis of his model is presented in section 1.1.

1.1 Garstang’s Model

Garstang’s model estimates city brightness as a function of distance, look-angle, city population, 

and atmospheric clarity. It assumes a mostly clear atmosphere and has been shown to reproduce 

the observed brightness values for a wide array of cities and geometries. Garstang models the 

city as a uniform circle, rather than a point source, which gives better results for observers near 

the city and can be used for determination of the sky brightness from within the city as well. His 

model assumes that the city lighting produces an output represented as lumens per head of 

population, a fraction of which is radiated directly into the upper hemisphere. A fraction of the 

downward radiated fraction is reflected upward with a Lambertian distribution. The model 

considers the effects of an inhomogeneous atmosphere using densities of both molecules and 

aerosols that decrease exponentially with height. The scattered light received at the observer’s 

position from an atmospheric elemental volume is computed by first illuminating the volume 

with (1) the upwelling, attenuated direct beam, and (2) first-order scattered radiance from an

elemental city light source. The illuminated atmospheric elemental volume then scatters this 

radiation downward along the observer’s line-of-sight (LOS), resulting in an attenuated radiance 

contribution at the observer’s location. Both the city and observer may be at an arbitrary height 

above ground level.

1.2 AAIM

The AAIM is a highly simplified and parameterized version of Garstang’s model with extensions 

to include cloudy skies and lunar illumination; the observer is currently located at ground level. 
2

It does not include the brightness distribution within cities or earth curvature effects as 

Garstang’s model does. The former, a complicated function of internal city illumination with 

scattering from buildings and roads, is being addressed by a 2009 Small Business Innovative 

Research (SBIR) proposal (12); for the latter, Garstang has shown that earth curvature effects are 

negligible for most cases where the cities are separated by a substantial distance.

To avoid redundancy only the salient points and equations found in, A Preliminary Urban 

Illumination Model, (13) will be presented here. Updated algorithms, particularly illumination 

through and reflected by clouds, are presented along with other relevant changes in the model.

Ambient illumination, which may be comprised of solar, lunar, galactic, and/or manmade 

lighting, strongly affects the ability of a sensor to “see” and therefore determine acquisition 

ranges. In nighttime warfare, the brightest sources of illumination are frequently either from the 

moon or urban areas. For mission planning, training purposes, and estimates of target 

acquisition ranges, it is necessary to have a model that will simulate natural and artificial lighting 

sources and then apply them to target acquisition problems such as ambient lighting conditions 

that vary over the course of a mission. To determine urban illumination levels due to artificial 

lighting, the Light Urban Model Effects (LUME) (13) used Walker’s (3) brightness-distance 

relationship 

B = CPD-α

, (1)

where B is the sky brightness, C and α are constants, P is the city population, and D is the 

distance from city center. This was, and still is, the basic model used. 

The improved model, AAIM, consists of four major pieces for estimating the overall broadband 

brightness. These consist of (1) the city source, (2) lunar illumination, (3) separating the

broadband city source term into its spectral components to simulate the artificial lighting spectral 

radiances, and (4) including effects from cloudy skies. 

2. Clear Skies: LUME Review

The brightness-distance relationship, valid for a zenith-pointing look-angle, was implemented in 

LUME (13). This implementation was modified with parameterizations for C and α (equation 1) 

as a function of city population and added directional dependencies for city light intensity (14). 

Two corrections to the zenith brightness were made: a Gaussian drop-off in intensity in the 

azimuthal direction and a secant function for the zenith direction.
3

2.1 Estimation of Constants Used in Brightness-Distance Relationship

Garstang (6, 7) estimated the values of C and α and compared his results to a limited set of 

observations (3). These values were tabulated in (14) for a number of population categories 

resulting in parametric curves used for determination of C and α as a function of population:

Log C = 0.6323 Log P – 2.4089, (2)

and

α = – 0.3405 Log P – 1.4304. (3)

2.2 Zenith-Angle Effects

The brightness-distance relationship does not include a model for the angular effects on observed 

brightness. It is used to compute brightness in the zenith direction (i.e., looking straight up) 

only. To correct this, the effects of off-angle views and the corresponding corrections to the 

zenith brightness were made as follows. 

To a first approximation, when viewed from far away, city lights would appear to increase in 

brightness as the secant of the zenith angle (5). To emulate this, a function was introduced to 

correct the zenith brightness for variations in zenith angle:

F(P, z) = f(z) = Α(P) sec(z), (4)

where A is a constant of proportionality determined from empirical data and parameterized by 

population, P, and z is the zenith angle in degrees (the zenith angle is the complement of the 

elevation angle). Figure 1 defines the geometry for the zenith angle (z), azimuth angle (β) and 

the elevation angle ε (= 90° – z).The constant of proportionality, Α, was determined by plotting 

the brightness for various city populations as a function of zenith angle. For each of the cities, a 

best-fit secant function with its corresponding constant of proportionality, Α, was determined to

vary as a function of city population. The estimates of A for various populations are shown in 

table 1.
4

Figure 1. Geometry used in AAIM.

Table 1. Estimates of the constant of proportionality, 

A, and the corresponding population, P.

log P Constant of proportionality, A

3.0 0.4

3.5 0.7

4.0 0.9

4.5 1.2

5.0 1.6

5.5 2.0

6.0 2.4

6.5 2.9

Due to the nature of the secant function approaching infinity for angles near 90°, it was only used

up to 80°. For the range 80–100°, the value of the secant law valid at 80° was used. Beyond 

110°, a weighted secant law is used. In summary, the zenith angle correction function, f(z), is 

computed as:

f(z) = A sec(z), z ≤ 80°, (5)

f(z) = A sec(80°), 80° < z ≤ 100°, (6)

f(z) = A [(1. – w) sec(80°) + w (|(sec(z)| – 1.)], 100° < z ≤ 110°, (7)

f(z) = A (|sec(z) | – 1.), 110° < z ≤ 180°, (8)

where w = (z – 100°) / 10.
5

2.3 Azimuth-Angle Effects

For the variations in urban brightness as a function of azimuthal angle (5), a Gaussian weighting 

function was employed and defined as:

[ /(2 )] 2 2

f( ) e −β γσ β = , (9)

where β is the azimuth angle (β = 0° when looking directly at the city, β = ±180° when looking 

directly away from the city), σ

2 is the variance of the distribution that defines the width of the 

Gaussian weighting function, and γ is a multiplicative factor used to modify the standard 

variance.

Based on qualitative observations, the variance of the Gaussian weighting function as a function 

of zenith angle was modified. By multiplying the variance by a variable γ = sec(90°-z) a new 

effective variance is produced resulting in a larger effective variance for small zenith angles and 

decreasing as the zenith angle approaches 90°. This ensures that the azimuthal dependence of 

the sky brightness decreases as one looks toward the zenith. 

A value for the variance that results in a 50% decrease in brightness over a 30° range at a zenith 

angle of 90° was selected. σ

2 is then determined to be:

σ

2 = 0.19776 rad2

. (10)

In summary, the azimuth angle correction function is computed in two steps. First, 

determination of the value for γ used to modify the variance:

γ = 1.0 / cos(90° - z) for 0° < z ≤ 90°, (11)

and 

γ = 1.0 for 90° < z ≤ 180°, (12)

then calculate the function itself:

[ /(2 )] 2 2

f( ) e −β γσ β = . (13)

After identifying the correction factors for the change in brightness due to zenith and azimuth 

angle effects, the broadband brightness from the city is calculated by combining equations 1, 4, 

and 13:

B = CPD-α f(z) f(β) (14)
6

3. Population and Location Database

As an upgrade to LUME, and since population is an integral input for the model, a limited 

database (cities info.txt) is provided with the program to supply not only the population of 

various worldwide cities, but also their latitude and longitude in decimal degrees (the degrees, 

minutes, seconds (DMS) format is not supported). Given that the population is the main driver

of city illumination, where possible the metropolitan area population, rather than the city 

population itself, was used. The available cities, as well as their latitude and longitude, may be 

found in appendix A and in the supplied cities info.txt data base. These latter two quantities are 

needed for determination of lunar phase and illumination at the top of the atmosphere. If the user 

desired city is not in the database, the user is asked to enter the population and latitude and 

longitude of that city, which may be optionally entered into the database by the user. The 

latitude and longitude and population for worldwide cities may be found at http://www.worldgazetteer.com/.

4. Lunar Illumination under Clear and Cloudy Skies

Prediction of lunar illumination under realistic atmospheric conditions that include clear skies, 

partly cloudy and overcast conditions, precipitation, and fog is handled by a modified version of 

the ILUMA model (15): a simple two stream radiative transfer model with three layers of 

atmosphere. Each layer is represented in terms of the cloud amount and cloud thickness or type. 

An albedo option allows one to account for realistic albedo conditions of the ground surface. 

Illumination is computed only for the moon; background sky effects (zodiacal light, starlight, 

etc.) are not included at this juncture.

The calculation of transmission of visible light through the atmosphere is based upon a threelayer radiative transfer model developed by Shapiro (16). The methodology combines a simple 

two-stream approximation in conjunction with tabulated mean climatological reflection and 

transmission coefficients. In the doubling method used by Shapiro, the reflection and 

transmission function of the layer consisting of n sublayers is computed by means of the known 

reflection and transmission functions in the separate layers. The three layer case is the simplest 

geometry that makes use of the standard cloud code information which categorizes clouds into

high, middle, and low cloud types.

The calculation of the lunar illuminance, taken as 0.267 lm m–2 for the moon in the zenith on a 

clear night, is based upon the procedure used by van Bochove (17). Illuminance as a function of 

the phase of the moon is based on the results of Russell (18).
7

ILUMA calculates the effect of cloud cover on illumination level by using traditional surface 

observations that report the type of cloud and percent cloud cover in the standard low, middle 

and upper levels. The input for the three layer model consists of the cloud base height and type 

for the three layers, the cloud fraction for each layer, and the surface albedo (reflectivity). 

Within these three levels Shapiro found that there was little difference between some of the 

cloud types and classified them into four cloud groups: cirrus (Ci)/cirrostratus (Cs), altostratus 

(As)/altocumulus (Ac), cumulus (Cu)/cumulonimbus (Cb), and stratus (St)/stratocumulus (Sc). 

The overall layer scheme is as follows:

• High - clear, thin and thick Ci/Cs

• Medium - clear, As/Ac

• Low - clear, clear (f/k), Cu/Cb or St/Sc

where (f/k) indicates fog or smoke reported. For clear skies, the fractional cloud amount for each 

layer is set to zero.

5. Illumination Due to City Lights Under Cloudy Skies

The brightness reflected from the cloud layer due to city lighting was calculated under a nonscattering atmosphere with an extinction coefficient of 0.15 km–1

, which equates to a visibility of 

~ 25 km. The total light output from the city is assumed to be LP lumens, where L is the lumens 

per head of the population, P. A value of L = 1000 was used (6). No provision is made for 

shielding by luminaries. Simple attenuation is carried out over the two paths considered –

upward from the city and downward along the observer’s LOS. The brightness was further 

modified by using the previous correction factors for falloff in both the zenith and azimuthal 

directions. The resulting equation is 

1 2 cos(z) cos( ) f(z)f( ) (z) e e

h r

LP B 2

2 2

−τ −τ θ β ρ

π

= , (15)

where h and r are the distances along the LOS from the city to the cloud base and from the 

observer’s LOS to the cloud base, respectively; z is the zenith angle; θ is the angle between the 

city’s zenith and its LOS; ρ is the cloud and angle dependent reflectivity (assumed to be 

Lambertian); and the optical depths along the paths considered are τ1 = k h and τ2 = k r, where k 

is the extinction coefficient in km–1

. Figure 2 presents the geometry; b is the cloud base height; 

and d is the distance from the observer to city center.
8

Figure 2. Geometry used for cloud cases.

Note: the cloud base is indicated by the dashed line

6. Spectral Composition of the Broadband Brightness 

The spectral composition of urban light is determined by identifying the types of lights used in 

typical cities and estimating the percentage that each light source contributes to the overall city 

light source. While the lunar illumination is included in the total broadband brightness, it is not 

currently included in the spectral values. The spectral radiance values over the sensor’s 

waveband are calculated based on the city brightness amount due to each individual light source. 

The method for accomplishing this is discussed in section 6.1.

6.1 City Light Types and their Spectral Composition

The types of lights that comprise urban settings and their spectral content must be known for the 

model to function, i.e., an illumination database of some nature is required. In any given city 

many light types are employed on city streets, highways, office buildings, shopping centers, 

stadiums, houses, parking lots, etc. The resulting mix of light is highly heterogeneous due to the 

variety of light source spectra, the effects of atmospheric scattering and absorption, and 

reflection from the ground. The mix contains both a broad continuum of radiation along with 

many superimposed emission lines at specific wavelengths. From 300–500 nm, a pseudo 

continuum is formed by the many emission lines of the mercury vapor and multivapor lights

(19). Beyond 500 nm, metal halide and high pressure sodium lamps are the primary contributors 

to the city light continuum.

In AAIM, a given mix of light sources was assumed and the proportion of light that is provided 

by each type was estimated from lighting data taken for El Paso, TX and Las Cruces, NM (20), 

and broken down into individual light types by percent. The results are presented in table 2.
9

Table 2. Breakdown of Street and flood lights in El Paso, TX and

Las Cruces, NM in 2007.

Light Type Percent of total light

Clear mercury Street 20.2%

High pressure sodium 77.9%

Street 63.3%

Area Floods 14.6%

Medal Halide Floods 1.9 %

Total 100 %

Using the lighting percentages in table 2, the amount of the brightness due to each light type is

determined by multiplying the broadband brightness by each percentage. For example, 

Bhigh pressure sodium = B × 0.779, etc. 

Each of the three light types listed in table 2 has a characteristic spectral distribution shown in

figure 3. Spectral distributions for these light types (21, 22) were used along with general 

knowledge of each light’s emission lines and continuum to build light spectra for the range 

300–1100 nm at 10 nm resolution. These distributions were digitized for each of the three light 

types and coded into the model.
10

Figure 3. Spectra of light sources in table 2.

Clear Mercury

0

20

40

60

80

100

300350400450500550600650700750800850900950

100010501100

Wavelength (microns)

High Pressure Sodium

0

20

40

60

80

100

300350400450500550600650700750800850900950

100010501100

Wavelength (microns)

Metal Halide

0

20

40

60

80

100

300350400450500550600650700750800850900950

100010501100

Wavelength (microns)
11

6.2 Radiant Energy Determination

The total radiant energy (in relative units) for each light type was computed by summing the area 

under the spectrum over the entire wavelength range for a given light type (300–1100 nm). The 

total radiant energy, Ei, for the specific light type (specified by the index i) is thus given by

∑

λ=

= ∆λ λ

1100

300

i i E e , (16)

where eiλ is the radiant energy at a specific wavelength taken from the digitized spectra and ∆λ is 

the bin width which is taken here as 10 nm. This quantity is precomputed for use in the code. 

The radiant energy (in relative units) corresponding to a specific wavelength band (specified by 

the index λ) is computed similarly, where the sum is over the user supplied wavelengths of 

interest, defined by λmin and λmax:

∑

λ

λ

λ λ = ∆λ max

min

i i E e . (17)

Finally, the broadband brightness can be separated into its spectral components by summing the 

contributions from each of the light types to each spectral band. The total city brightness in a 

wavelength band defined by λmin and λmax is calculated as follows:

i

i

i B

E

E

B

3

i 1

∑

=

λ

λ= (18)

where Bi is the proportion of the city broadband brightness associated with a specific light type.

6.3 Convert Brightness to Radiance Units

The final step in calculating the radiance contribution due to urban illumination is to convert 

from photometric units (nL) to radiometric units (W/m

2

/sr/μm). In this case, we first converted 

to nL/μm by normalizing the spectral radiance value computed above by the width of the 

wavelength interval in microns. Equation 19 was used for the final conversion: 

B (W/m2

/sr/μm) = B (nL/μm) × 1.464×10–8. (19)

7. Validation

7.1 Clear Atmosphere

The results for lunar illumination at the surface were compared with results from ILUMA and 

found to be in agreement. The results from AAIM were compared to an equivalent formulation 

by Albers (8). Since his model is only valid for the brightness at the zenith, comparisons were 
12

made for a zenith and azimuthal angles of zero, with no correction factors considered. The 

results of the two models agreed to a factor less than 2. 

Validation was also done via comparison with results from Garstang (6). His figures 2 and 3 

were digitized and compared with AAIM values computed for the same location and geometries. 

Figure 4 shows brightness as a function of zenith angle for the city of Denver; the distance was 

fixed at 40 km. Garstang’s values were converted from magnitude/arcsec2 to nL using his

equation 19, and presented here as equation 20.

B = 34.08 exp (20.7233 – 0.92104 V), (20)

where V is the visual magnitude of the sky in magnitude/arcsec2 and B is the is the sky 

brightness in nL. Garstang’s figure 3 was also compared with AAIM with results presented in 

figure 5.

Figure 4. Sky brightness due to Denver as a function of zenith angle at a distance of 40 km. 

Note: No lunar illumination values are included.

Considering that AAIM does not account for scattering processes, the results are reasonable and 

allows confidence that the model produces reasonable results.

0.0

200.0

400.0

600.0

800.0

1000.0

-90 -60 -30 0 30 60 90

Angle (degrees)

Brightness (nL) 

 AAIM

 Garstang
13

Figure 5. Sky brightness due to Denver as a function of distance for a zenith angle of zero. 

Note: No lunar illumination values are included.

Spectral results were compared to those of Aube (25) who measured a zenith brightness of 

0.3 × 10–5 w m–2μm–1sr–1 at Mt. Palomar Observatory, CA on a moonless night in May of 2005. 

Running AAIM for the same parameters at a distance of 120 km from Los Angeles, CA we find 

a value of 0.34 × 10–5 w m–2

μm–1sr–1. This almost exact agreement must be tempered by the 

fact that the greater Los Angeles area extends at least halfway to Mt. Palomar.

7.2 Cloudy Atmosphere

The spectral output under cloudy skies was compared with that of Desrochers and Hiett (26) who 

measured sky glow on a moonless night under cloudy conditions at Hanscom Air Force Base

(HAFB), approximately 25 km outside of Boston, MA. The observed base heights ranged from 

0.3 km to 1.0 km and their figure 2 shows a broad peak from about 550 to 650 nm and another 

highly peaked region at ~825 nm. These two peaks correspond well with the spectral lines of 

high pressure sodium lamps (see figure 3). If we ignore those two peaks, we get an eyeball 

average of 0.25 × 10–3 w m–2μm–1sr–1 (Note: there is some confusion as to their ordinate scale, 

which is assumed here to be scaled up by a factor of 104). By running AAIM and using input 

values from (26), i.e., a distance of 25 km from Boston on 16 February 1998, at 0400 

coordinated universal time (UTC) under a overcast sky comprised of Sc/St clouds with a base of 

1.1 km, we find a value of 0.30 × 10–5 w m–2

μm–1sr–1. This discrepancy of two orders of 

magnitude could easily be because their location on HAFB was only partly shielded from local 

light sources. If we reduce the distance to 12.5 km, thereby simulating an increase in lighting 

brightness, we find a value of 0.41 × 10–3 w m–2μm–1sr–1 in good agreement with their values. 

Finally, a quote from Garstang (27) would seem appropriate here: “Since the two sites are so 

close to each other, the disparity between the zenith brightnesses indicate that very local lighting 

is relatively more predominant than is accounted for in many sky brightness models.”

0

1

2

3

4

5

0.8 1 1.2 1.4 1.6 1.8 2 2.2

Log Distance (km) 

Log Brightness (nL) 

 AAIM

 Garstang
14

8. Program Usage

Depending upon the options chosen, the program provides:

• Sky brightness due to city lights in a clear atmosphere

• Sky brightness due to city lights under cloudy skies

• Lunar brightness in a clear atmosphere

• Lunar brightness under cloudy skies

• Spectral radiance of city lights in a clear atmosphere

• Spectral radiance of city lights under cloudy skies.

The program requires user input be either interactive or file-directed. To become familiar with

usage of the program, default values are provided (table 3). The required inputs are the 

beginning/ending sensor wavelength (μm), country and city of interest, zenith and azimuth 

angles (degrees), horizontal distance from the observer to the city (km), date and time (UTC), 

and the ground albedo (see table 4 for some representative values (15)). In addition, when 

clouds are of interest, additional required inputs are cloud type (table 5), and cloud fraction 

amounts for the three layers. The average cloud base heights needed to determine the vertical 

distance of the city light reflection from the cloud base are internally selected from the four 

available cloud categories. If so desired, the user may change the cloud base height for the cloud 

type selected. Cloud reflection coefficients are provided through ILLUMA and are based on the 

work of Shapiro (16). The latitude and longitude for the location is obtained from the city 

database discussed elsewhere in this document.

Table 3. Program inputs and their default values (from (15)).

Input Default Value

Beginning/ending wavelength 0.6 - 0.9 μm

City/Country Boston, US

Date 2 February 2008

UTC 0200 

Surface Albedo 0.25

State of cloudiness:

 High - no clouds

 Middle - no clouds

 Low - overcast with Cu/Cb

Zenith angle 10.0°

Azimuth angle 0.0° (towards city center)

Distance from city center 25 km
15

Table 4. Albedos of various surfaces.

Soils Dry Wet Unspecified

Dark 0.13 0.08

Light 0.18 0.10

Dark-ploughed 0.08 0.06

Light-ploughed 0.16 0.08

Clay 0.23 0.16

Sandy 0.25 0.18

Sand 0.40 0.20

White sand 0.55

Surfaces

Asphalt 0.10

Lava 0.10

Tundra 0.20

Steppe 0.20

Concrete 0.30

Stone 0.30

Rock 0.35 0.20

Dirt road 0.25 0.18

Clay road 0.30 0.20

Fields Growing Dormant

Tall grass 0.18 0.l3

Mowed grass 0.26 0.19

Deciduous trees 0.18 0.12

Coniferous trees 0.14 0.12

Rice 0.12

Beet wheat 0.18

Potato 0.19

Rye 0.20

Cotton 0.21

Lettuce 0.22

Snow

Fresh 0.85

Dense 0.75

Moist 0.65

Old 0.55

Melting 0.35

Ice

White 0.75

Grey 0.60

Snow and ice 0.65

Dark glass 0.10
16

Table 5. Cloud base heights for cloud types in AAIM.

Level Cloud Type Cloud Base

(km)

High Ci/Cs 9.3 *

Middle As/Ac 4.0†

Low Cu/Cb 1.2 †

Low Sc/St 1.1†

* ref 23

† ref 24

The user will be asked to provide the population and latitude and longitude, if a city/country is 

not in the supplied database (cities info.txt). This user supplied city information can then be 

added to the database for future reference, if desired. 

Depending on the options chosen, the program will provide values for the city and lunar 

broadband brightness, or cloud reflected city and transmitted lunar brightness in nL. Spectral 

values are provided in units of W/m2

/μm/sr. Lunar illumination is not included in the spectral 

output, but will be incorporated in the next version. For comparison purposes, when either the 

default values or clouds are selected, the program provides the cloud reflected brightness for an 

observer looking directly at the city center zenith.

Finally, two sample input files are provided for file-directed input usage, one for full moon 

(full_moon.dat) and one for new moon values (new_moon.dat).

9. Conclusion

This model builds on previous research that predicts the broadband brightness as a function of 

population and distance from the city center. To that distance-based model, azimuth and zenith 

dependencies are added to predict changes to the brightness for off-angle viewing directions. 

The ability to calculate illumination from either city or lunar sources has been included and 

reflection and transmission due to clouds is considered. Finally, the types of light sources 

employed in urban lighting have been updated to current usage. These data define the spectral 

composition of the broadband illumination.

This model is simple and fast. Several caveats concerning the model are compiled here. The 

current model caveats are as follows:

• The broadband brightness model developed for visual waveband is assumed to 

hold true for near-infrared too.

• Model parameters are selected for a single atmospheric state.

• Cities are treated as point sources.
17

10. Future Work

Future efforts will include the following:

• Separating the lunar illumination into spectral components

• Allowing for a variable turbid atmosphere

• Inclusion of single scattering effects

• Shielding by luminaries

• Addition of background light (zodiacal, etc.)

• Addition of foreign city light types

• Comparison with the World Atlas of the Artificial Night Sky Brightness (28)

• Allowing city reflection from partially cloudy skies

• Extend light type spectra to near-IR wavelengths

• Allow the observer to be located at an arbitrary height above ground level
18

11. References

1. Walker, M. F. The California Site Survey. Publ. Astron. Soc. Pacific 1970, 82, 672–698.

2. Walker, M. F. Light pollution in California and Arizona. Publ. Astron. Soc. Pacific 1973,

85, 508–519.

3. Walker, M. F. The Effects of Urban Lighting on the Brightness of the Night Sky. Publ. 

Astron. Soc. Pacific 1977, 89, 405–409.

4. Treanor, P. J. A Simple Propagation Law for Artificial Night-Sky Illumination. The 

Observatory 1973, 93, 117–120.

5. Berry, R. L. Light Pollution in Southern Ontario. Journal of the Royal Astronomical Society 

of Canada 1976, 70 (3), 97–115.

6. Garstang, R. H. Model for Artificial Night-Sky Illumination. Publ. Astron. Soc. Pacific

1986, 98, 364–375.

7. Garstang, R. H. Night-Sky Brightness at Observatories and Sites. Publ. Astron. Soc. Pacific

1989, 101, 306–329.

8. Albers, S.; Duriscoe, D. Modeling Light Pollution from Population Data and Implications 

for National Park Service Lands. The George Wright Forum 2001, 18 (3).

9. Aubé, M.; Franchomme-Fossé, L.; Robert-Staehler, P.; Houle, V. Light Pollution Modeling 

and Detection in a Heterogeneous Environment: Toward a Night Time Aerosol Optical 

Depth Retrieval Method. Proc. of SPIE 2005, 5890.

10. Kocifaj, M. Light-Pollution Model for Cloudy and Cloudless Night Skies with GroundBased Light Sources. Applied Optics 2007, 46, 15.

11. Kocifaj, M. Light Pollution Simulations for Planar Ground-Based Light Sources (preprint).

Applied Optics 2008.

12. http://www.dodtechmatch.com/DOD/Opportunities/SBIRView.aspx?id=A08-

057&page=print (accessed October 2008).

13. Shirkey, R. C. A Preliminary Illumination Model; ARL-TR-4320; U.S. Army Research 

Laboratory: WSMR, NM, 2007 (DTIC No. ADA474479).

14. Gouveia, M. J.; Cianciolo, M. E.; Higgins, G. J. Night Vision Goggles Operations Weather 

Software (NOWS); AFRL-VS-TR-2001-1580; U.S. Air Force Research Laboratory: 

Hanscom AFB, MA, 2000.
19

15. Duncan, L. D.; Sauter, D. P.; Miller, A. Natural Illumination Under Realistic Weather 

Conditions, ILUMA; ASL-TR-0221-21; EOSAEL 87, Vol 21; U.S. Atmospheric Sciences 

Laboratory: WSMR, NM, October 1987.

16. Shapiro, R. Solar Radiative Flux Calculations from Standard Surface Meteorological 

Observations; AFGL-TR-82-0039; U.S. Air Force Geophysical Laboratory: Hanscom AFB, 

MA, 1982 (DTIC No. ADA118775).

17. van Bochove, A. C. The Computer program ILLUM: Calculation of the Position of Sun and 

Moon and the Natural Illumination; PHL 1982-13; Physics Laboratory TNO, The Hague, 

The Netherlands; 1982.

18. Russell, H. N. The Stellar Magnitude of the Sun, Moon and Planets. Astrophysical Journal

1916, 43, 103–129.

19. Lane M. C.; Garrison R. G. The Night-Sky Spectrum of the City of Toronto. Journal of the 

Royal Astronomical Society of Canada 1978, 72 (4), 198–205.

20. Private communication, El Paso Electric Co., El Paso, TX, 2007.

21. Finch, D. M. Atmospheric Light Pollution. Journal of the Illuminating Engineering Society

1978, 7 (2), 105–117.

22. http://www.highend.com/support/training/metalhalide.asp (accessed October 2008).

23. Jursa, A. S. Ed.; Handbook of Geophysics and the Space Environment; Air Force Geophysics 

Laboratory, 1985; pp 16–44 (DTIC No. ADA 167000).

24. Low, R.D.H. Cloud Transmission Module CLTRAN; ASL-TR-0221-9; U.S. Army Research 

Laboratory: WSMR, NM, 1987 (DTIC No. ADB332821).

25. Aube, 2009, http://www.graphycs.qc.ca/aubema/recherches/data/Data/northamerica/usa/california/mount-palomar/2005/palomar-zenith-may-2005.png (accessed 

October 2008).

26. Desrochers, P. R.; Hiett, T. Cloud impacts on urban glow. 29th International Conference on 

Radar Meteorology; Montreal, Canada; United States; 12–16 July 1999; pp 436-439. 

27. Narisada, K.; Schreuder, D. Light Pollution Handbook, Astrophysics and Space Science 

Library, Vol 322; Springer, The Netherlands; 2004, pp 861 (ISBN 1-4020-2665-X (HB); 

1-4020-2668-8 (e-book)).

28. Cinzano, P.; Falchi, F.; Elvidge, C. D. The First World Atlas of the Artificial Night Sky 

Brightness. Mon. Not. R. Astron. Soc. 2001, 328, 689–707.
20

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21

Appendix A. Population of Select Worldwide Cities (Metropolitan areas used 

when available.)

Population Country City Latitude Longitude

349000 Afghanistan Herat 34.333 62.200

2536300 Afghanistan Kabul 34.517 69.200

324800 Afghanistan Quandahar 30.996 65.476

300600 Afghanistan Mazar-e Sharif 67.110 67.110

56200 Afghanistan Baghlan 36.120 68.703

300000 Albania Tirane 41.332 19.817

4447000 Algeria Algier 36.775 3.060

22390 Andorra Andorra la Vella 42.500 1.500

2000000 Angola Luanda 13.232 13.232

21514 Antigua and Barbuda St. John's 17.118 –61.846

12431000 Argentina Buenos Aires –34.667 –58.500

1315500 Argentina Córdoba 18.917 –96.917

1226000 Armenia Yerevan 40.167 44.517

29998 Aruba Oranjestad 12.517 –70.033

1040719 Australia Adelaide –34.917 138.583

21622 Australia Alice Springs –23.700 133.883

1676389 Australia Brisbane –27.467 153.033

307700 Australia Canberra –35.283 149.133

66291 Australia Darwin –12.467 130.833

3188000 Australia Melbourne 144.963 144.963

1256035 Australia Perth –31.933 115.833

3665000 Australia Sydney –33.867 151.207

128808 Australia Townsville –19.217 146.800

1600000 Austria Vienna 48.200 16.367

1713300 Azerbaijan Baku 40.367 49.883

171542 Bahamas Nassau 25.066 –77.339

155000 Bahrain Al-Manamah 26.217 50.567

140401 Bahrain Manama 26.215 50.588

10979000 Bangladesh Dhaka 23.717 90.417

6700 Barbados Bridgetown 13.100 –59.617

1666000 Belarus Minsk 53.850 27.500

949070 Belgium Brussels 50.833 4.333

5845 Belize Belmopan 17.217 –88.800

30340 Bhutan Thimphu 27.533 89.717

713400 Bolivia La Paz –16.500 –68.167

310000 Bosnia Sarajevo 43.850 18.383

138000 Botswana Gaborone –24.750 25.917

1800000 Brazil Brasília –15.783 –47.917

3699000 Brazil Porto Alegre –30.028 –51.229

3307000 Brazil Recife –8.100 –34.883
22

Population Country City Latitude Longitude

10556000 Brazil Rio de Janeiro –22.900 –43.233

3180000 Brazil Salvador –12.963 –38.512

17711000 Brazil Sao Paulo –23.533 –46.617

52300 Brunei Bandar Seri Begawa 4.883 114.933

1113674 Bulgaria Sofia 42.667 23.300

500000 Burkina Ouagadougou 12.367 –1.517

300000 Burundi Bujumbura –3.367 29.317

900000 Cambodia Phnom Penh 11.550 104.917

1299446 Cameroun Yaound 3.850 11.583

3401000 Canada Montreal 45.545 –73.639

1130761 Canada Ottawa 45.417 –75.717

24570 Canada Riviere-du-Loup –69.269 –69.269

715515 Canada Quebec 46.833 –71.250

233923 Canada Saskatoon 52.167 –101.533

4657000 Canada Toronto 43.650 –79.383

2116581 Canada Vancouver 49.267 –123.117

5113149 Canada Toronto 43.670 –79.387

694668 Canada Winnipeg 49.883 –97.150

61797 Cape Verde Praia 14.917 –23.517

529555 Chad N'Djamena 12.167 14.983

5261000 Chile Santiago –33.450 –70.667

12033000 China Beijing 39.917 116.433

5566000 China Changchun 43.887 125.325

5293000 China Chengdu 30.711 104.088

3896000 China Chongging 29.555 106.548

3153000 China Dalian 38.914 121.616

5162000 China Guangzhou 23.127 113.342

3763000 China Handan 36.610 114.481

6389000 China Hangzhou 30.274 120.173

5475000 China Harbin 45.750 126.683

6097000 China Hong Kong 22.320 114.239

4789000 China Jinan 36.665 116.995

3375000 China Nanjing 32.056 118.798

4376000 China Qingdao 36.108 120.416

14173000 China Shanghai 31.100 121.367

5681000 China Shenyang 41.828 123.416

10239000 China Tianjin 39.104 117.252

4750000 China Wuhan 30.583 108.900

3352000 China Xi'an 34.265 108.944

6834000 Colombia Bogota 4.600 –74.083

3831000 Colombia Medellin 6.251 –75.576

937580 Congo Brazzaville 4.233 15.233

5068000 Congo Kinshasa –4.300 15.300

315909 Costa Rica San Jose 9.933 –84.083

3359000 Cote d'Ivoire Abidjan 5.317 –0.083

930753 Croatia Zagreb 45.800 15.967

2241000 Cuba Havana 23.133 –82.367
23

Population Country City Latitude Longitude

186400 Cyprus Nicosia 35.167 33.367

1215771 Czech Republic Prague 50.100 14.433

1339395 Denmark Copenhagen 55.750 12.417

395000 Djibouti Djibouti 11.550 43.167

15853 Dominica Roseau 15.300 –61.383

3601000 Dominican Republic Santo Domingo 18.467 –69.900

1500000 Ecuador Quito –0.233 –78.500

3995000 Egypt Alexandria 31.214 29.944

150000 Egypt Aswan 24.083 32.933

10772000 Egypt Cairo 30.050 31.250

972810 El Salvador San Salvador 13.667 –89.167

400000 Eritrea Asmara 15.333 38.967

471608 Estonia Tallinn 59.433 24.717

2200186 Ethiopia Addis Ababa 9.050 38.700

2115 Falkland Islands Stanley –51.750 –57.933

200000 Fiji Suva –18.133 178.417

515765 Finland Helsinki 60.133 25.000

630000 France Bordeaux 44.833 –0.567

347900 France Nice 43.700 7.250

9638000 France Paris 48.867 2.333

419596 Gabon Libreville 0.500 9.417

44188 Gambia Banjul 13.467 –16.650

1279000 Georgia T'bilisi 41.717 44.817

3471418 Germany Berlin 52.533 13.417

3251000 Germany Dusseldorf 51.225 6.776

6559000 Germany Essen 51.458 7.015

3700000 Germany Frankfurt 50.112 8.681

82220000 Germany Hamburg 53.550 9.983

3067000 Germany Koln 50.941 6.960

3200000 Greece Athens 37.967 23.717

3103000 Greece Athina 37.979 23.717

4439 Grenada St. George's 12.067 61.733

160000 Guam Hagatna 13.467 144.750

1150452 Guatemala Guatemala City 14.633 –90.517

1508000 Guinea Conakry 9.483 –13.717

200000 Guinea-Bissau Bissau 11.867 –15.650

248500 Guyana Georgetown 6.800 –58.167

1500000 Haiti Port Au Prince 18.533 –72.333

310000 Herzegovina Sarajevo 43.850 18.383

1500000 Honduras Tegucigalpa 14.083 –87.233

4160000 Brazil Belo Horizonte –19.816 –43.954

2008546 Hungary Budapest 47.500 19.083

103036 Iceland Reykjavik –64.150 21.850

4154000 India Almadabad 72.566 72.566

5544000 India Bangalore 12.967 77.583

12900000 India Calcutta 22.500 88.333

6639000 India Chennai 13.060 80.250
24

Population Country City Latitude Longitude

11680000 India Delhi 28.667 77.233

6833000 India Hyderabad 17.385 78.487

18042000 India Mumbai 18.933 74.583

294149 India New Delhi 28.635 77.225

3485000 India Pune 18.520 73.857

3420000 Indonesia Bangdung –6.912 107.607

11500000 Indonesia Jakarta –6.133 106.750

2410800 Iran Mashad 36.267 59.567

1204882 Iran Shiraz 29.633 52.567

1378935 Iran Tabriz 38.083 46.300

7705036 Iran Tehran 35.667 51.433

313552 Iraq Ad-Diwaniyah 31.978 44.900

333142 Iraq Al-'Amarah 31.830 47.148

1100790 Iraq Al-Basrah 30.293 47.292

428933 Iraq Al-Hillah 32.497 44.446

292274 Iraq Al-Kut 32.529 45.828

1174022 Iraq Al-Mawsil 36.340 43.144

502842 Iraq An-Najaf 31.352 44.096

424311 Iraq An-Nasiriyah 31.039 46.236

910381 Iraq Arbil 36.557 44.385

307229 Iraq Ar-Ramadi 33.432 43.312

119665 Iraq As-Samawah 43.281 43.281

683261 Iraq As-Sulaymaniyah 45.450 45.450

6956562 Iraq Baghdad 33.333 44.433

183486 Iraq Ba'qubah 33.747 44.662

1100790 Iraq Basra 30.520 47.824

910381 Iraq Irbil 36.180 44.016

454090 Iraq Karbala' 32.406 43.867

618149 Iraq Kirkuk 35.468 44.395

1174022 Iraq Mosul 36.335 43.137

2550500 Israel Jerusalem 31.783 35.217

380000 Israel Tel Aviv 32.066 34.778

364779 Italy Florence 43.767 11.250

4251000 Italy Milano 45.464 43.137

993400 Italy Naples 40.850 14.283

3012000 Italy Napoli 40.840 14.253

2693383 Italy Rome 41.800 12.600

104000 Jamaica Kingston 17.967 –76.800

1157846 Japan Hiroshima 34.383 132.450

3377000 Japan Nagoya 35.156 136.916

10609000 Japan Osaka 34.678 135.507

28025000 Japan Tokyo 35.667 139.750

963490 Jordan Amman 31.950 35.933

280200 Kazakhstan Astana 51.167 71.500

193300 Kazakhstan Petropavl 54.883 69.217

2000000 Kenya Nairobi –1.283 36.817

151060 Kuwait Kuwait City 29.333 48.000
25

Population Country City Latitude Longitude

631000 Kyrgyzstan Bishkek 42.883 74.767

442000 Laos Vientiane 17.967 102.600

874000 Latvia Riga 56.667 106.167

1100000 Lebanon Beirut 33.867 35.500

170000 Lesotho Maseru –29.317 27.483

1000000 Liberia Monrovia 6.300 –10.783

950000 Libya Benghazi 32.117 20.067

1682000 Libya Tripoli 32.900 13.183

5067 Liechtenstein Vaduz 47.133 9.533

590100 Lithuania Vilnius 54.683 25.317

75622 Luxembourg Luxembourg 49.617 6.133

444229 Macedonia Skopje 42.000 21.467

1000000 Madagascar Antananarivo –18.867 47.500

260000 Malawi Lilongwe –13.967 33.817

1145000 Malaysia Kuala Lumpur 3.133 101.700

62973 Maldives Male 4.174 135.507

746000 Mali Bamako 12.650 –8.000

9183 Malta Valletta 35.900 14.533

20000 Marshall Islands Majuro 7.083 171.133

480000 Mauritania Nouakchott 18.150 –15.967

134516 Mauritius Port Louis –20.167 57.500

3908000 Mexico Guadalajara 20.667 –103.333

18131000 Mexico Mexico City 19.400 –99.150

3416000 Mexico Monterrey 25.685 –100.305

676700 Moldova Chisinau 47.000 28.833

30400 Monaco Monaco 43.750 7.383

619000 Mongolia Ulan Bator 47.900 106.867

3535000 Morocco Casablanca 33.589 –7.609

1220000 Morocco Rabat 34.033 –6.850

3017000 Mozambique Maputo –25.967 32.583

4458000 Myanmar (Burma) Yangon 16.783 96.167

161000 Namibia Windhoek –22.567 17.100

535000 Nepal Kathmandu 27.700 85.317

724096 Netherlands Amsterdam 52.350 4.900

1208091 New Zealand Auckland –36.917 174.783

397974 New Zealand Wellington –41.283 174.783

974000 Nicaragua Managua 12.100 –86.300

398265 Niger Niamey 13.533 2.083

339000 Nigeria Abuja 9.167 7.183

13488000 Nigeria Lagos 6.450 3.400

2741260 North Korea Pyongyang 39.000 125.783

483401 Norway Oslo 59.917 10.750

350000 Oman Muscat 23.617 58.633

201000 Pakistan Islamabad 33.667 73.133

11774000 Pakistan Karachi 24.850 67.033

6030000 Pakistan Lahore 31.545 74.341

12299 Palau Koror 7.350 134.517
26

Population Country City Latitude Longitude

450668 Panama Panama City 8.967 –79.533

250000 Papua New Guinea Port Moresby –9.500 147.117

502426 Paraguay Asuncion –25.267 –57.667

7443000 Peru Lima –12.050 –77.050

10818000 Philippines Manila 14.583 120.983

458053 Poland Gdansk 54.383 18.667

3488000 Poland Katowice 19.024 19.024

1642700 Poland Warsaw 52.250 21.000

677790 Portugal Lisbon 38.733 –9.133

422000 Puerto Rico San Juan 18.467 –66.117

300000 Qatar Doha 25.250 51.600

2351000 Romania Bucharest 44.433 26.100

9299000 Russia Moscow 55.750 37.700

5132000 Russia Saint Petersburg 59.933 30.333

594701 Russia Vladivostok 43.150 131.883

232733 Rwanda Kigali –1.933 30.067

32859 Samoa Apia –13.831 –171.752

2397 San Marino San Marino 43.933 12.433

3328000 Saudi Arabia Riyadh 24.650 46.767

1199629 Scotland Glasgow 55.883 –4.250

1729823 Senegal Dakar 14.667 –17.433

1574050 Serbia Belgrade 44.833 20.500

25000 Seychelles Victoria –4.633 55.467

1300000 Sierra Leone Freetown 8.500 –13.250

3587000 Singapore Singapore 1.300 103.833

446600 Slovakia Bratislava 48.167 17.167

330000 Slovenia Ljubljana 46.067 14.500

35288 Solomon Islands Honiara –9.467 159.950

900000 Somalia Mogadishu 2.033 45.350

3092000 South Africa Cape Town –35.917 18.367

1480530 South Africa Johannesburg –26.133 27.900

749921 South Africa Port Elizabeth –33.967 25.600

1104479 South Africa Pretoria –25.750 28.200

4239000 South Korea Puan –13.828 –171.744

11968000 South Korea Seoul 37.533 127.000

1510000 Spain Barcelona 41.383 2.183

4072000 Spain Madrid 40.400 –3.683

1994000 Sri Lanka Colombo 6.917 79.867

924505 Sudan Khartoum 15.600 32.533

200970 Suriname Paramaribo 5.833 –55.167

47020 Swaziland Mbabane –26.333 31.133

703627 Sweden Stockholm 59.333 18.050

129423 Switzerland Bern 46.950 7.433

1080000 Switzerland Zurich 47.367 8.550

1549932 Syria Damascus 33.500 36.300

2643439 Taiwan (ROC) Taipei 25.083 121.533

524000 Tajikistan Dushanbe 38.633 68.850
27

Population Country City Latitude Longitude

1360850 Tanzania Dar es Salaam –6.850 39.300

7221000 Thailand Bangkok 13.733 100.500

366476 Togo Lome 6.133 1.217

34000 Tonga Nukualofa –21.150 –175.233

52451 Trinidad and Tobago Port-of-Spain 10.633 –61.517

887800 Tunisia Tunis 36.800 10.183

3190000 Turkey Ankara 39.917 32.833

9413000 Turkey Istanbul 41.017 28.967

518000 Turkmenistan Ashgabat 41.332 19.817

3839 Tuvalu Funafut –8.517 179.217

773463 Uganda Kampala 0.317 35.417

7640000 UK London 51.500 –0.167

2637000 Ukraine Kiev 50.417 133.717

363432 United Arab Emirates Abu Dhabi 24.467 54.367

2200000 United States Houston 29.750 –95.367

6945000 United States Chicago 41.883 –87.650

3912000 United States Dallas 32.781 –96.797

1300000 United States Denver 39.755 –104.988

3785000 United States Detroit 42.330 –83.046

3918000 United States Houston –95.363 –95.363

13129000 United States Los Angeles 34.050 –118.250

16626000 United States New York 40.717 –74.000

4398000 United States Philadelphia 39.952 –75.164

4051000 United States San Francisco 37.775 –122.419

3927000 United States Washington D.C. –77.024 –77.024

876156 United States Honolulu 21.300 –157.817

1330440 Uruguay Montevideo –34.883 –56.183

2106000 Uzbekistan Tashkent 41.267 69.217

26100 Vanuatu Port Vila –17.750 168.300

3153000 Venezuela Caracas 10.500 –66.933

345489 Venezuela Merid 8.400 –71.133

3678000 Vietnam Hanoi 21.017 105.867

6424519 Vietnam Ho Chi Minh City 10.767 106.717

1972011 Yemen Sanaa 15.400 44.233

1168454 Yugoslavia Belgrade 41.332 19.817

1184169 Zimbabwe Harare –17.833 31.500
28

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29

Acronyms and Abbreviations

AAIM An Army Illumination Model

As altostratus

Ac altocumulus

ARL U.S. Army Research Laboratory

Cb cumulonimbus

Ci cirrus

Cs cirrostratus 

Cu cumulus

DMS degrees, minutes, seconds

HAFB Hanscom Air Force Base

LOS line-of-sight 

LUME Light Urban Model Effects

NVGs night vision goggles

SBIR Small Business Innovative Research

Sc stratocumulus

St stratus

UTC coordinated universal time
30

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2800 POWDER MILL ROAD

ADELPHI MD 20783-1197

1 ARMY RESEARCH LABORATORY

ATTN AMSRD ARL CI ED

DR HOOCK

BUILDING 1622

WSMR NM 88002-5501

1 ARMY RESEARCH LABORATORY

ATTN AMSRD ARL CI EM 

D KNAPP

BUILDING 1622

WSMR NM 88002-5501

COPIES ORGANIZATION

2 ARMY RESEARCH LABORATORY

ATTN AMSRD ARL CI EM

DR SHIRKEY

BUILDING 1622

WSMR NM 88002-5501

1 NAVAL RESEARCH LABORATORY

MARINE METEOROLOGY DIVISION

DR A GOROCH

7 GRACE HOPPER AVE

MONTEREY CA 93943

3 US ARMY NATICK SOLDIER 

CENTER

MR ROBERT AUER

KANSAS STREET

NATICK MA 01760 

1 NORTHROP GRUMMAN

MS M GOUVEIA 

100 BRICKSTONE SQUARE

ANDOVER MA 01810

1 ATMOSPHERIC ENVIRONMENTAL 

RESEARCH INC

DR G SEELEY

131 HARTWELL AVENUE

LEXINGTON MA 02421-3136

1 SCIENCE APPLICATIONS

INTERNATIONAL CORPORATION

LEANDRO DELGADO

731 LAKEPOINTE CENTRE DRIVE

O’FALLON IL 62269-3064

3 US ARMY NATICK SOLDIER 

RD&E CENTER

ATTN AMSRD NSR TS M B AUER

15 KANSAS STREET

NATICK MA 01760-5056

1 DIRECTOR, USA TRAC ANALYSIS 

CENTER

ATTN ATRC FMA T GACH

255 SEDGWICK AVE 

FORT LEAVENWORTH KS 66027-

2345
31

NO. OF

COPIES ORGANIZATION

1 DIRECTOR, USA TRAC ANALYSIS 

CENTER

ATTN ATRC FMA S GLASGOW 

255 SEDGWICK AVE

FORT LEAVENWORTH KS 

66027-2345

1 DIRECTOR, USA TRADOC 

ANALYSIS CENTER

ATTN ATRC WEC D DURDA

WSMR NM 88002-5502

TOTAL: 25 (1 PDF, 24 CDS)
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