for research inc lawrence remote circularly … · 2014. 9. 27. · mohamed abdel-razik adnan aslam...

7 AD-AO92 077 KANSAS UNIV/CENTER FOR RESEARCH INC LAWRENCE REMOTE --ETC FIG 17/9CIRCULARLY POLARIZED MEASUREMENTS OF RADAR BACKSCATTER FROM TER--ETC(U)JUL 80 W H STILES, F T ULABY, E A WILSON DAAK7O-78C-0121

UNCLASSIFIED CRINC/RSL-TR-393-2 ETL-O234 NL... flfIIflfflflIflIflf-mhElllEllEEEEEhmln//EllEEI-EEEEEiggI-mEl.EEEE.IHEE-EElEEIIIIEIIIIEI

CRINC DEMOTE SENSING LABORATORY

It.Lt

IllLEtVEM ;

ETL-0134

CIRCULARLY POLARIZED MEASUREMENTSOF RADAR BACKSCATTER FROM TERRAIN

AND SNOW-COVERED TERRAIN

0

in W. H. StilesF. T. UlabyE. A. Wilson

J. C. Holtzman 0TrC

July 1980 S ELF EC

Approved for public release; distribution unlimited

Prepared for:

U. S. Army Engineer Topographic LaboratoriesL - Fort Belvoir, Virginia 22060

* ~ '~' THE UNIVERSITY OF KANSAS CENTER FOR RESEARCH, INC.* 2291 Irving Hill Drive-Campus West

Lawrence, Kansas 66045 ii

jCI(913)RL POLARIZED MEASUREMENTS

OF RDARBACKSCATTER FROM TERRAINADSNOW-COVERED TERRAIN

Remote Sensing LaboratoryRSL Technical Report 393-2

W. H. Stiles

F. T. Ulaby

E. A. Wilson

J. C. Holtzman

Fawwaz T. Ulaby, Principal Investigator

July 1980

{Prepared for:U. S. Army Engineer Topographic Laboratories

Fort Belvoir, Virginia 22060

REMOTE SENSING LABORATORY

DESTROY THIS REPORT WHEN NO LONGER NEEDED.DO NOT RETURN IT TO THE ORIGINATOR.

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(4 EOR WUMNTTINPAGE BEOECMLEIGFR2. GOVT ACCESSION NO. 3. RECIPIENT'S CATALOG NUMBER

j ETL 34 --4~ c774. 1 .. twd Subtitle) S. TYPE OF REPORT & PERIOD COVERED

RCULARLY OLARIZED ZASUREMENTSCotatRpr(Fnl

6. PERFORMING ORG. REPORT NUMBER

FAw z AN -L-CVEE RSL Tech. Report 393-211. CONTRACT ORGRANT NUM01ER11e)

J W. H. tiles; T.Alabyj E. A./Wilson ) DAAK7,9-78-C-0l 21S. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASKC

University of Kansas Center for Research, Inc. AREA AWORK UNIT NUJU3EAV Remote Sensing Laboratory - West Campus

Lawrence, KS 66044 YLI I. CONTROLLING OFFICE NAME AND ADDRESS

U. S. Army Engineer Topographic Laboratories IJli,Fort Belvoir, VA 22060 !

14. MONITORING AGENCY NAME &ADDF" .t from Controllng Office) 1S. SECURITY CLASS. (of this report)

cijT~>~~i 'f-Unclassified15s.. DECL ASSIFIC ATION/ DOWNGRADING

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16. DISTRIBUTION STATEMENT (of this Report)

Approved for public release; distribution unlimited.

17. DISTRIBUTION STATEMENT (of the abstract entered In Block 20, It different from Report)

I S. SUPPLEMENTARY

NOTES

19. K EY WORDS (Cont inue on reverse side )I necessary and identity by block number)

Backscatter, Microwave Remote Sensing, Radar Remote Sensing, Circular Pola-rization, Terrain, Snowcover

TO. ABST A T (Continue on reverse side It necessary and Identify by block number)ITrhis report covers a measurement program to obtain circularly polarized

radar backscatter coefficient tvttdata along with associated ground-truthinformation on snow-covered terrain. Snow-covered grass, asphalt and ice

Iwere observed a selected frequencies from 8 to 18 GHz for angles of inci-dence between 0r(nadir) and 80* Also included are some analyses of theeffects of snowcover on the backscatter from terrain.

DD O A." 1473 EDITION OF I NOV 6 IS OSOLETE UNCL SSIFIEDS/N 102-14-601 1SESCURI-tY CLASPICATION OF TNIS PAGE (ftev bae Enteed)

.. iJqmty CLASSIFICATION OF THIS PAGE(W'Ibu Data BatmfG

SECURITY CLASSIFICATION OF THIS PA0EItMhon Dole BEatm

TABLE OF CONTENTS

Page

PREFACE .. ... ... ............................. . ..

LIST OF FIGURES ...... ......................... . i...

LIST OF TABLES ... ... .. .. ......................... v

1.0 INTRODUCTION ...... ... ........................ 1

2.0 ANALYSES OF THE RADAR BACKSCATTER COEFFICIENT OF TERRAIN 2

2.1 Coniferous and Deciduous Trees .... ............. 2

2.1.1 Coniferous Trees .... .. ................ 2

2.1.2 Deciduous Trees .. ...... ............... 6

2.1.3 Mixed Deciduous and Coniferous Trees ... ...... 6

2.1.4 Comparison of Deciduous and Coniferous Trees 9

2.2 Asphalt and Concrete Surfaces ..... ............. 9

2.3 Plowed and Bare Ground ...... ................. 9

3.0 RADAR BACKSCATTER COEFFICIENT OF SNOW-COVERED TERRAIN . ... 14

3.1 Ground-Truth Measurements Applicable to Snowcover . 14

3.2 Backscatter Measurements ...... ................ 20

3.2.1 Snow of Various Depths on Top of Grass .. ..... 21

3.2.2 Snow of Various Depths on Top of Roads .. ..... 33

3.2.2.1 Asphalt .... .. ................. 33

3.2.2.2 Concrete .... ................. .. 48

3.2.3 Ice and Snow ....... .................. 48

3.3 Analyses of Snowcover Effects ..... ............. 56

3.3.1 Linear and Circular Polarization BackscatterRelationship .... ... .................. 56

3.3.2 Effects of Snow on the Backscatter Responseof Grass ..... .................... ... 64

3.3.3 Effects of Snow on the Backscatter Responseof Asphalt and Concrete ............... .. 64

3.3.4 Ice and Snow ....... .................. 71

4.0 RECOMMENDATIONS ...... ....................... ... 75

REFERENCES ...... .. ............................ . 78

APPENDIX A - RADAR BACKSCATTER COEFFICIENT co DATA

APPENDIX B - RADAR SNOWPILE SCAN MEASUREMENTS

PREFACE

The Remote Sensing Laboratory wishes to thank Mr. Jerry Patterson

of the Steamboat Resort in Steamboat Springs, Colorado and

Mr. Joe Reddick, Ranger of the Arapaho National Recreation Area for

their cooperation in arranging the usage of their facilities. The

participation and help of the following individuals in the data-acqui-

sition and processing phases is appreciated:

Dennis Anderson

Dennis Carmichael

Chip Gabel

George Eger

John Williamson

Tom Near

Dan Barbour

Craig Dobson

Mohamed Abdel-Razik

Adnan Aslam

This report was prepared under Contract No. DAAK70-78-C-0121 for the

U. S. Army Engineer Topographic Laboratories, Fort Belvoir, Virginia.

The Contract Officers Representative (COR) was Mr. Richard .e--j

DistribUt C - -A8ajjsbi-t caest-

-Av djo

LIST OF FIGURES

Page

Figure 2-1 A comparison of the angular response of ao at16.2 GHz and 17.0 GHz for shortleaf pine atthree sites ........ .................... 4

Figure 2-2 A comparison of the angular response of ao at8.6 GHz and 10.2 GHz for shortleaf pine atSite 5 in August and November .... ........... 5

Figure 2-3 A comparison of the angular response of ao at16.2 GHz and 17.0 GHz for oak and hickoryat two sites ....... ................... 7

Figure 2-4 A comparison of the angular response of a0 at16.2 GHz and 17.0 GHz for oak and hickoryat Site 6 in August and November .... ......... 8

Figure 2-5 A comparison of the angular response of o at16.2 GHz and 17.0 GHz for oak and hickory,shortleaf pine, and mixed oak, hickory andshortleaf pine ....... .................. 10

Figure 2-6 A comparison of the angular response of ao at16.2 GHz and 17.0 GHz for dry concrete anddry asphalt ....... ................... 11

Figure 2-7 A comparison of the angular response of ao at16.2 GHz and 17.0 GHz for bare groundand plowed ground .... ................ ... 13

Figure 3-la Location of test sites for the snowcovermeasurements ..... ................... ... 15

Figure 3-lb Location of the three test sites in theSteamboat Springs, Colorado area .... ......... 16

Figure 3-ic Location of the test sites within SteamboatSprings, Colorado .... ................ ... 17

Figure 3-id Location of the lake-ice test site atShadow Mountain Lake in Colorado.. .......... ... 18

Figure 3-2 Overall view of Test Site No. 1 shown on2/14/80, deep snow over grass .... .......... 22

Figure 3-3 Angular response of o° of snow , 6 incheson grass ....... ..................... 24

Figure 3-4 Spectral response of o of snow , 6 incheson grass ....... ..................... 25

Figure 3-5 Angular response of ao of snow > 6 inches(wet) on grass ....... .................. 27

Figure 3-6 Spectral response of ao of snow , 6 inches(wet) on grass ....... .................. 28

ii

Page

Figure 3-7 View of Test Site No. 1 on 2/25/80 after thedeep snow was cleared, leaving a traceof snow ...... .. ..................... 29

Figure 3-8 Angular response of o° of snow-traceon grass ..... .................... ... 31

Figure 3-9 Spectral response of ao of snow-traceon grass ..... .................... ... 32

Figure 3-10 View of Test Site No. 2 with deep snow on2/15/80 and after clearing and a 6-inchsnowfall on 2/22/80 .... .............. ... 34

Figure 3-11 Angular response of o° of snow > 6 incheson asphalt ...... .. ................... 36

Figure 3-12 Spectral response of o° of snow > 6 incheson asphalt ...... .. ................... 37

Figure 3-13 Angular response of co of snow6 inches on asphalt ... ............... ... 39

Figure 3-14 Spectral response of o of snow6 inches on asphalt ... ............... ... 40

Figure 3-15 Angular response of o° of snow3 inches on asphalt ... ............... ... 42

Figure 3-16 Spectral response of ao of snow3 inches on asphalt ... ............... ... 43

Figure 3-17 View of Test Site No. 3 with a traceof snow on 2/17/80 ...... ............... 44

Figure 3-18 Angular response of o° of snow-traceon asphalt ...... .. ................... 46

Figure 3-19 Spectral response of o° of snow-traceon asphalt ...... .. ................... 47

Figure 3-20 Overall view of Test Site No. 4 showingthe snow-covered lake-ice on 2/27/80 withopen water seen in the background .... ........ 49

Figure 3-21 Shadow Mountain Lake test site .... ......... 50

Figure 3-22 Angular response of o° of snow on ice ... ...... 52

Figure 3-23 Spectral response of ao of snow on ice .. ..... 53

Figure 3-24 View of the snowpile and the carobserved on 2/17/80 ... ............... ... 54

Figure 3-25 Variation in received power Pr for the scandata at 10.2 GHz, RIL polarization at threeangles of incidence: (a) 00 (nadir),(b) 100, and (c) 700 ..... ............... 55

Figure 3-26 Angular response of ao of snowpile and caron asphalt . . . 0 58

Page

Figure 3-27 Spectral response of ao of snowpileon asphalt ....... .................... 59

Figure 3-28 Linear and circular ao comparison ondry concrete ..... ................... ... 60

Figure 3-29 Linear and circular ao0 comparison onasphalt ...... .. ..................... 61,

Figure 3-30 Linear and circular polarization a0comparison on bare grass ..... ............. 62

Figure 3-31 Comparison of data reported inReference [1] with the data obtainedfor this report .... ................. ... 63

Figure 3-32 Effects of snow on the backscatterfrom grass ...... .. .................... 65

Figure 3-33 Effects of snow on the backscatterfrom asphalt .... ............ ......... 66

Figure 3-34 Effects of snow on the linear polari-zation backscatter from asphalt .... .......... 68

Figure 3-35 Effects of snow on the linear polari-zation backscatter from concrete ........... ... 69

Figure 3-36 Backscatter from snow using linearpolarization ..... ................... ... 70

Figure 3-37 Backscatter from smooth ice for linearand circular polarization. Linearpolarization data from Onstott [8] ... ........ 72

Figure 3-38 Backscatter coefficient of a sea-icepressure-ridge from Onstott [8] ... ....... 73

Figure 3-39 Backscatter from a snowpile, a car, andan asphalt parking lot ... .............. ... 74

iv

--------------------- ~ .. tJ~*

LIST OF TABLES

Page

TABLE 2-1 Coniferous Tree Ground Truth ..... ........... 3

TABLE 2-2 Deciduous Tree Ground Truth ..... ........... 3

TABLE 3-1 Ground-Truth Data for Snow > 6 Incheson Grass ....... ..................... 23

TABLE 3-2 Ground-Truth Data for Snow : 6 Incheson Grass ....... ..................... 26

TABLE 3-3 Ground-Truth Data for Snow-Traceon Grass ..... ..................... ... 30

TABLE 3-4 Ground-Truth Data for Snow 6 Incheson Asphalt ........ .................... 35

TABLE 3-5 Ground-Truth Data for Snow 6 Incheson Asphalt ........ .................... 38

TABLE 3-6 Ground-Truth Data for Snow3 Inches on Asphalt .................. ... 41

TABLE 3-7 Ground-Truth Data for Snow-Traceon Asphalt ... ... .. ................... 45

TABLE 3-8 Ground-Truth Data for Lake-Ice .... .......... 51

TABLE 3-9 Description of Snowpi.le: Test SiteNo. 3 .... .. ... ...................... 57

KvVT

1.0 INTRODUCTION

This report covers the conclusion of a measurement program to

obtain circularly polarized radar backscatter coefficient (00) data

along with associated ground-truth information on terrain. A previous

report [1] documented the circular polarization response of various

types of tree-covers, road surfaces, and bare-soil targets. This

report includes analyses of the previously reported backscatter coef-

ficient data, measurements and observations on the effects of snow-

cover on the various terrain classes, and recommnendations for future

studies in this area. Section 2, although by no means detailed,

provides heuristic explanations for the different scattering coef-

ficient responses reported in (1]. This section points to the need

for more measurements and theoretical developments to provide a firmer

basis for the given explanations. In Section 3, the snow-covered-

terrain data is presented, along with discussions of the ground-truth

data and the scattering behavior of snow. The final section points

out areas of interest that are not well-understood and recommnends

experimental arnd theoretical programs designed to improve the under-

standing of the circularly polarized return from terrain and to remove

some of the ambiguities observed in the data.

2.0 ANALYSES OF THE RADAR BACKSCATTER COEFFICIENT OF TERRAIN

In the initial phase of this program, measurements were taken

on various types of terrain. The targets studied included coniferous

and deciduous trees, asphalt and concrete surfaces, and plowed and

bare.ground. Data were acquired at six frequencies in the 8-18 GHz

range using RR, RI, and LL circular polarization and at incidence

angles from 0' to 800.

This section will provi4de a brief review and interpretation of

these terrain measurements. For more detailed information, refer to

Wilson, et al. [1].

2.1 Coniferous and Deciduous Trees

All tree measurements for this program were taken at six sites

in the Mark Twain National Forest located in southern Missouri. The

sites were visited in August and in November.

2.1.1 Coniferous Trees

The type ,of coniferous tree studied was shortleaf pine. Data were

acquired at three sites. Relevant ground truth is summnarized in Table 2-1.Figure 2-1 compares the angular response of the three sites in August.

For incidence angles less than 300, Site 1, the densest, exhibits a

higher return. Note also, however, that Sites 2 and 5 differ signifi-

cantly in density, height, and circumference, yet their response is nearly

identical. It is possible that the return from the densest site is domni-

nated by the vegetation, even at low angles of incidence, while at the

other two sites a significant ground-return is present, below 300. One

might argue that this ground-return at lower angles should result in a"peak" near vertical incidence. It must be recognized, however, that the

observed response is strongly dependent on the "roughness" of the forest

floor, which is covered with deadwood, various other types of vegetation,

and fallen leaves. Another possible explanation is that Site 1 is so dense

that the upper part of the canopy almost forms a surface. Figure 2-2 com-

pares the angular respo'nse at Site 5 in August versus November. Considering

the limits of system accuracy and precision, it appears that coniferous

trees exhibit negligible seasonal change.

2

TABLE 2-1Coniferous Tree Ground Truth

Heightto Average Trunk Tree Soil

Height Branches Circumference Density Moisture NeedleSite Date (mn) (in) (in) (100 m? 0-2c)Mitr

1 AUG 7.5 2.5 0.33 80 22% 68%2 AUG 10.4 4.3 0.58 60 22% 66%5 AUG 3.5 0.6 0.30 30 16% 65%5 NOV 3.5 0.6 0.30 30 23% 63%

TABLE 2-2

Deciduous Tree Ground Truth

Heightto Average Trunk Tree Soil

Height Branches Circumference Density Moisture LeafSite Date (in) (mn) (in) (100 m') (0-2 cm) Moisture

3 AUG 6.5 3.2 0.89 30 26% 59%6 AUG 6.0 0.6 0.39 35 12% 55%3 NOV 6.5 3.2 0.89 30 29% --6 NOV 6.0 0.6 0.38 35 29% -

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2.1.2 Deciduous Trees

The type of deciduous trees studied was a mix of oak and hickory.

Data were acquired "with leaves" at two sites in August and "without

leaves" at the same two sites in November. Relevant ground truth is

summnarized in Table 2-2. Figure 2-3 compares the angular response of

the two sites in August. The plots reveal a rather wide spread in

level between the two sites at all angles of incidence. The density

of trees per unit area and the average tree height were about the same

for both sites, but the tree "volumes" were quite different.' The can-

opy volume (branches) for Site 6 extended from 0.6 m above the ground

to the top of the canopy while the canopy of Site 3 had essentially

no branches in the lower three meters. Consequently, it is conceivable

that the greater range of volume scatterers in Site 6 is responsible

for the higher values of 00. It is possible also that the cause may

be due to some other geometrical difference between the trees of the

two canopies. In order to resolve such questions and to improve the

understanding of the mechanisms responsible for the backscatter from

tree canopies,. it is necessary to conduct measurements with a high-

resolution system capable of measuring the backscatter contribution as

a function of range into the canopy. This recommendation is discussed

4 in more detail in Section 4.Figure 2-4 compares the response at Site 6 in August versus Novem-

ber. At the higher angles of incidence, the defoliation has resultedin a reduction in level of approximately 4-5 dB; at the lower angles of

incidence, the moist November soil has apparently caused the level to

rise above that of the August data.

2.1.3 Mixed Deciduous and Coniferous Trees

An area of mixed oak, hickory and shortleaf pine also was studiedduring this experimental program. Although it was not possible to

determine the exact percentage of each type of tree, the site appearedto be approximately 60%-70% deciduous. The response of this site was

similar to that of Site 6 which was totally deciduous.

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2.1.4 Comparison of Deciduous and Coniferous Trees

Figure 2-5 compares the response of coniferous, deciduous, and

mixed stands of trees. Over most of the angular range investigated,

the response of the coniferous-tree site is approximately 5 dB

below that of the other two sites.

This comparison is based upon August data; a similar comparison

for November data would show little difference in level among thetree-types, except near nadir where apparently there is a significantground-return associated with the defoliated deciduous trees.

2.2 Asphalt and Concrete Surfaces

Measurements on asphalt and concrete surfaces were conducted at

Johnson County Industrial Airport near Olathe, Kansas. Both surfaces

were measured under wet and dry conditions. In general, one would

expect that the addition of water to an asphalt or concrete surface

should have two effects: (1) the average dielectric constant should

increase and (2) the water should tend to 'smooth" the surface. Theangular respon ?se of ao for wet and dry concrete, however, showed

little difference between the two conditions; the same was true for

asphalt, except at nadir where the wet surface gave approximately a5 dB greater return than the dry surface. These measurements suggest

that there was little effect due to changes in dielectric constant,especially on concrete. The 5 dB increase at nadir on asphalt maybe due to a "smoothing" effect, but quite likely it reflects the

difficulty of making precise measurements at nadir on a smooth sur-

face where a slight angular error causes a significant drop in thelarge coherent component of the return. Comparison of dry concrete

versus dry asphalt indicates that the asphalt is slightly rougher,

as expected from physical observation (Figure 2-6); comparison of

the two surfaces when wet shows little difference in roughness.

2.3 Plowed and Bare Ground

Measurements on plowed and bare ground were conducted north of

Lawrence, Kansas. As with other surfaces, the return should be a

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function of (1) the surface dielectric constant, which is governed

primarily by the soil moisture, and (2) the surface roughness.

During the period of time that the two sites were available for

observation, the soil moisture varied over a rather narrow range, so

the effect of dielectric-constant changes was minimal. There was,

however, a dramatic difference in surface roughness between the two

sites on both a micro- and macro-scale; this difference in roughness

is quite evident from the backscatter data such as that presented in

Figure 2-7.

12

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13

3.0 RADAR BACKSCATTER COEFFICIENT OF SNOW-COVERED TERRAIN

These additional measurements were conducted by the University of

Kansas Center for Research, Inc., Remote Sensing Laboratory, using the

MAS 8-18/35 microwave scatterometer system which was described in detail

in the previous report [1]. The system specifications, precision and

calibration methods were identical for this program and therefore will

not be repeated. Briefly, however, the systems cover six frequencies

between 8 and 18 GHz, operate in three circular polarization states

(RR, RL, LL) and can observe angles of incidence from 0* (nadir) to 800.

Data were acquired on three groups of terrain classes with snow

cover: (1) Grass, (2) Road Surfaces, and (3) Snow and Ice. Four test

sites were examined in the measurements. All sites were located in

the Colorado mountains; the locations are illustrated in Figure 3-1a.

Figures 3-lb, c and d give the test-site locations at a larger scale.

Test Site No. 1 was a short-grass (hay) field. Test Sites Nos. 2 and 3

were asphalt and Test Site No. 4 was an ice- and snow-covered lake.

More detailed descriptions are given in later sections. The radar

backscatter coefficient data are given in Appendices A and B.

3.1 Ground-Truth Measurements Applicable to Snow Cover

The choice of the ground-truth parameters measured is determined by

the significance that parameter is expected to play in the wave-target

interaction mechanism and by the time and manpower restrictions associated

with the data acquisition. The snow measurements were obtained at each

site from a snow-pit dug down to ground level. Photographs of these areas

are shown in several of the ground-truth tables. These pits allow access

to the snow in order to obtain snow samples and to observe the layering

of the snow. The following snow parameters were measured:

1. Depth

2. Stratification

3. Density

4. Water Equivalent

14

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Test Sites 2 i:::ia . aal ' _ : .N sL-motps 1 25 & 3 64i'ta$aaaa a

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Aaa 13 an. aaa 3.aaa-ta,. -. 7 c, &v ~ ____taaala~~~~~~la.0 -.i-r -aCaISt2aCaa n aa

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STEAMBOAT SPRINGS-COLORADO

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170

TEST SITE #2--"-... -..

Figure 3-1c Location of the Test Sites within Steamboat Springs,Col orado.

17

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Figure 3-id Location of the Lake-Ice Test Site at ShadowMountain Lake in Colorado.

18

5. Wetness

6. Temperature

7. Grain Size

8. Surface Roughness Photograph

Detailed explanations of technique and procedure on the above

measurements may be found in another report [2].

The depth (d) and stratification were determined with a meter stick.

Two techniques were used to enhance the layer boundaries for their deter-

mination. Visual observations found most layer boundaries. However, for

slight gradations in density, this technique was augmented by sliding a

plastic card vertically through the snow and feeling the resistance to

its motion at the layer boundaries. The snow density (P) was determined

for each layer by taking a known volume of snow and finding its weight.

The water equivalent (W) of snow is defined as the depth of water that

would be obtained from the complete melt of a column of snow. The relation-

ship between depth, density, and water equivalent is given by

W =snow d cm

Pwater

where pwater is approximately unity, therefore

W = Psnow d cm

The snow wetness or percent liquid water within the snowpack is

by far the most difficult snow parameter to measure. The most accurate

method developed thus far is the freezing calorimeter. Calorimetric

techniques have been employed for many years by physicists and

chemists. The method was adapted to field-use by Leaf [3]. The basis

for operation is to have a known volume of solvent with known heat

capacity in an insulating container (thermos bottle) with provisions for

measuring temperature. The solvent used was a silicone compound which

remains in the liquid state at -40C, which is its initial temperature.

Ifa known weight of wet snow is then added and the solution is allowed

to reach an equilibrium temperature, then by knowing the weights of sol-

vent and wet snow, the initial and final temperatures within the calori-

meter, and the latent heat of fusion of water, the liquid water content

19

"! A

can be calculated. The following equation gives the liquid water content

by weight (-mw):

mw _ (Wi + E)(Tf - Ti) Csi + TfCs

100- WsLf Lf

where

Wi = weight of silicone fluid

E = calorimeter constant

Tf = final temperature of solution

Ti = initial temperature of silicone

Csi = specific heat of silicone

Cs = specific heat of ice

Lf = latent heat of fusion

Ws = weight of snow

The snow wetness by volume (mv ) is then calculated from mw and the snow

density Psnow:

mv Psnow mw

The snow temperature profile was measured with a digital thermometer

and grain sizes were determined visually. Macrostructure roughness can

be seen from roughness grid photographs. Soil moisture was measured for

the grass targets.

3.2 Backscatter Measurements

This section covers the backscatter and ground-truth data obtainedfrom snow-covered terrain.

20

- . ....

3.2.1 Snow of Various Depths on Top of Grass

This field (Test Site No. 1) was a very flat, 40-acre field in the

valley south of Steamboat Springs, Colorado. The location is shown in

Figure 3-lb. The grass (hay) was in its winter-dormant state and had

been cut to approximately 2.5 cm. This test site was observed under

three different snow conditions. The overall view of the test site is

given in Figure 3-2. Close-up photographs are given for each data set

in Tables 3-1 to 3-3. Snow of greater than 6-inch depth was observed

on two different days (2/14/80 and 2/16/80). Although the snow depths

were the same for each of these data sets (64 and 63 cm), the angular

and spectral responses are quite different as a result of the influence

of snow wetness (my).vFigures 3-3 and 3-4 give the angular and spectral response of 0

for a case in which the surface layer (0-5 cm) of the snow is slightly

wet (mv = 1.41%), while the interior of the snowpack is dry (mv = 0).

The dryness of the snowpack is inferred from the snow temperature pro-

file shown in Table 3-1.

Figures 3-5 and 3-6 give the angular and spectral responses to the

same snowpack under isothermal conditions. In this case, the entire

snowpack is at OC (Table 3-2) and therefore, wetness exists at all

levels. The snow wetness in the surface layer is very high at 5.2%

by volume.

The same test site also was observed with a trace of snow. These

conditions were obtained by clearing an area on the field. Figure 3-7

illustrates this area. The angular and spectral responses of o° are

given in Figures 3-8 and 3-9. The ground-truth data are given by

Table 3-3.

As a result of other constraints on the use of the MAS systems and

as a result of uncooperative weather conditions, these were the only

sets obtained over grass. Analyses of these data sets are furnished

in Section 3.3.

21

- - - -- - -

......... .u f. .

Figure 3-2 Overall view of Test Site No. I shown on2/14/80, deep snow over grass.

22

, I

DATE: 2/14/80

TIME: 1245-1535

TARGET: Grass

TYPE OF SET: Snow a 6-inch

LOCATION: Hibbert'sSteamboat Springs, COTest Site #1

Grid Size 2.4 cmWater

Layer Number Depth (cm) Density Equivalent Grain Size(From Ground) (To Layer Top) p(g/cm) W(cm) (mm)

Overall 64 -- 16.1 NA8 64 0.226 -- 0.57 59 0.214 -- 16 46.5 0.335 -- 15 35 0.414 -- 1-1.54 32 0.313 -- 1-1.53 27 0.400 -- 1-1.52 25 0.279 -- 2-31 10 0.246 -- 2-3

TARGET CONDITIONS 6Height (cm): 2.5 - _. .'

Soil Moisture (0-5 cm): 52.8% 4---by wt. 7T" , ..Temperature °C: 0.2(Ground) 2

WEATHER OBSERVATIONSoff, -z .:T jAir Temperature °C: 3.0 " -T:. .. T_Relative Humidity: 85% ---- _-,?. -

-2 ,General: -_ --- - _.

Cloudy, warm and humid - . . I-4 J

Light snow during set I __

SNOW WETNESS mv_, - -L

0-2 cm: 1.41% Air 60 40 20 0

2-5 cm: 0.65% Depth (above ground level, cm)

TABLE 3-1

23

0

- - >

olop a)

00

IA0

0~~0

CC

000

3: adJ

CD 0

> C C0o 0-

- CP

VD - 03-0K

cc 0 b 0

I1~ 4 .D 0

Ml C

040

(9P - U0.3.40 BIOe

24)

Target: Snow ?6 inches on GrassDate: 2/14/80Time: 1245 - 1535Water Equivalent (cmh 16. 1Snow Wetness m (%): 1 4

Angle of10 - I ncidence Polarization

300 RL300 RR

"- 700 RL

0 70' RR

-- 0

---- 9-- i -

-20

V)-30

-401-8 10 12 14 16 18

Frequency (GHz)j

Figure 3-4 Spectral response of' of snow >, 6 incheson grass.

DATE: 2/16/80

TIME: 1400-1630

TARGET: Grass

TYPE OF SET: Snow > 6-inch


Grid Size 2.4 cm

WaterLayer Number Depth (cm) Density Equivalent Grain Size(From Ground) (To Layer Top) p(g/cm3 ) W(cm) (mm)

Overall 63 -- 16.9 NA98 63 0.350 -- 17 57 0.214 -- 16 45 0.322 -- 1-25 35 0.408 -- 14 32 0.331 -- 1-1.53 27 0.400 -- 12 25 0.279 -- 2-31 10 0.246 -- 2-4

TARGET CONDITIONS 6Height (cm): 2.5 6 C!

Soil Moisture (0-5 cm): 52.4% 4Temperature 0C: 0.2 by wt. . , I,____

(Ground)

WEATHER OBSERVATIONS0i 0Air Temperature °C: 2.8 o

Relative Humidity: 63% CL .__ ____.

General: 1- -2

Warm, partly cloudy -4 -- - l i i i

SNOW WETNESS m i

0-5 cm: 5.2% 1

5-10 cm: 0.24% Air 60 40 20 0

10-15 cm: 1.78% Depth (above ground level, cm)

TABLE 3-2

26

CC

ILI0

CM 0

oe CD 0 04-

P- 0

> 0. CD0w

E L.Al CD~, * 0'

C2 m a)C" (D ~ m ta Q

ca 7 I C

10 w

0.0100

(SP) o jUG!31usr U83 uuenS

27

Target: Snow 26 lnches(wet) on GrassDate: 2/16/0Time: 1400 - 1630Water Equivalent (cm). 16. 9Snow Wetness m. M%: 5. 2

Angle of10 -I ncidence Polarization

- u300 RI300 RR

---- 700 RI0 700 RR

'-1

2-20

-3

01

8 10 12 14 16 18Frequency (GHz)

Figure 3-6 Spectral response of co of snow >, 6 inches(wet) on grass.

28

Figure 3-7 View of Test Site No. 1 on 2/25/80 after the

deep snow was cleared, leaving a trace of snow.

29

DATE; 2/25/80

TIME: 1730-1930

TARGET: Grass See Figure 3-7

TYPE OF SET: Snow Trace


WaterLayer Number Depth (cm) Densitt Equivalent Grain Size(From Ground) (To Layer Top) p(g/cm) W(cm) (nn)

Overall O-1 -- 0-1 NA987654321 0-1 -- 2-3

TARGET CONDITIONS: 6

Height (cm): 2.5 10

Soil Moisture (0-5 cm): 33.8% 4 17.

Temperature °C: 0.1 by wt. - 4(Ground) 2

WEATHER OBSERVATIONS - --L- II-

Air Temperature 'C: 0.0 =

Relative Humidity: 67% .- t TL_. .. . .

General: 41rt- 4 ltf -4-+4--... ..... .... ............. -Clear, cooling towards - -.-. --- - .... - -end of data set -4 _- - --

SNOW WETNESS my -,,

Wet but not measurable Air 60 40 20 0due to sample sizeDepth (above ground level, cm)

TABLE 3-330

00

L- C a

C C

0)I

0D CD C=)C

r-4 0,

I I

-0

cU 0

o IcoCD

P. 1J Cc4J/ 4

cl0

c~j a)

31

Target: Snow Trace on GrassDate: 2/25/80Time: 1730 - 1930Water Equivalent (cmh 0 - 1Snow Wetness m, (%): -

Angle of

10 I ncidence Polarization300 RL300 RR700 RL

0 - 700 RR

-3

a)

%0

-40o 4 0 n nA

8 10 12 14 16 18Frequency (GHz)

Figure 3-9 Spectral response of co of snow-trace on grass.

32

3.2.2 Snow of Various Depths on Top of Roads

3.2.2.1 Asphalt

Two asphalt areas were observed: Site No. 2 and Site No. 3

(Figure 3-1c). Test Site No. 2 was the model-airplane runway at

the Steamboat ski resort at Steamboat Springs, Colorado. This runway

is approximately 150 m in length and 15 m wide. It is unused and

normally snow-covered during the winter months. Three depths of snow

were observed at this site. Figure 3-10 shows this area before and

after it had been cleared.

When this runway was in its normal snow-covered state (before

clearing), a data-set was obtained. Figures 3-11 and 3-12 give the

angular and spectral responses of ao for wet snow (mv = 3.75%) and

an isothermal snowpack. Ground-truth data are given in Table 3-4.

Figures 3-13 and 3-14 present the angular and spectral response

of ao over 6-inch, slightly wet snow (mv = 1.0%). This snowcover was

the result of two snowfalls that occurred on consecutive days and there-

fore, a boundary was not apparent between the snowfalls. The previous

day, 2/21/80, a 3-inch layer was observed. The angular and spectral

responses of o to this very-wet-snow case (mv = 4.23%) are shown in

Figures 3-15 and 3-16. System problems were encountered during the

data set requiring an abbreviated measurement set. The ground-truth

data for these two sets are given in Tables 3-5 and 3-6.

The other asphalt area observed was the high-school parking lot

at Steamboat Springs, Colorado (Test Site No. 3). It was snowing

during the data set, but the weather was very warm and only a trace

of snow was on the parking lot. Figure 3-17 shows this area.

Figures 3-18 and 3-19 show the angular and spectral responses of 0° .

The ground-truth data are given in Table 3-7.

33

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _

(a)

(b)

Figure 3-10 View of Test Site No. 2 with deep snow on2/15/80 and after clearing and a 6-inchsnowfall of 2/22/80.

34

DATE: 2/15/80

TIME: 1315-1600

TARGET: Asphalt

TYPE OF SET: Snow > 6-inch P''

LOCATION: Model Airplane RunwayLTV ResortSteamboat Springs, COTest Site #2

WaterLayer Number Depth (cm) Density Equivalent Grain Size(From Ground) (To Layer Top) p(g/cmJ) W(cm) (mm)

Overall 5 -- 15.7 NA9876 55 0.246 --5 40 0.260 --4 34 0.280 --3 20 0.327 --2 15 0.333 --1 14 0.357 --

TARGET CONDITIONS 6

Height (cm): NA I- -

Soil Moisture (0-5 cm): NA 4--T--_ ------ ___ ! -. .Temperature *C: 0.0 rT - ..... -

(Ground) -

WEATHER OBSERVATIONS .

Air Temperature *C: 2.7 0

Relative Humidity: 86%

General: -2Warm and clear

-4 ,SNOW WETNESS my

0-5 cm : 3 .75% __" _" ___....... .... _ .5-10 cm: 0.27% Air 60 40 20 0

Depth (above ground level, cm)

TABLE 3-4

35

C~J 004dC

- fv ~GCD

CU

crr4-;

000(

CU

S'

f- LA< 0

(fiP aD OK CD 0Q

0.0

E 0

CD n a.L

Al (D CA. CD 0

14.-- CD

crI V

C)

Y 4 LL.

-m P--4

(SP) @0 Juspillo3o B6us

36

Target: Snow2>6 Inches on AsphaltDate: 2/15/80Time: 1315 - 1600Water Equivalent (cmh. 15.7Snow Wetness m. (%: 3.8

Angle of

10 Incidence Polarization300 RL300 RR

--- 700 RL

0 700 RR

0

20 -I-P

-30

(A3

-30 ..- --- -

-40 1 I I n I8 10 12 14 16 18

Frequency (GHz)

Figure 3-12 Spectral response of a° of snow 7 6 incheson asphalt.

37

.........

Quarter is shown

DATE: 2/22/80

TIME: 0945-1400

TARGET: Asphalt

TYPE OF SET: Snow, 6-inch


WaterLayer Number Depth (cm) Density Equivalent Grain Size(From Ground) (To Layer Top) p(g/crn3) W (cm) (mmn)

Overall 14.5 -- 2.62 NA987654321 14.5 0.181 -- 0.5-1

TARGET CONDITIONS 6 ______________

Height (cm): -NA V L _Soil Moisture (0-5 cm): NA 4 T ~ ii4._Temperature *C: 0.0 - __~

(Ground) 2 ~--- -

WEATHER OBSERVATIONS ~-~7iZT ~ I~Air Temperature *C: -0.2 4.0 __ W__

Relative Humidity: 100% 7General: -2 [__ ~ __

SNOW WETNESS m _ - -

0-5 cm: i.o% ________________Air 60 40 20 0Depth (above ground level, cm)

TABLE 3-5

38

C.0)

a) Ia)

CD

CDC

CD 'D-4 CDI C)

(aP) 0ID JU13111003 6utj8sIe3Su

%0

'00

0C CD 00

0 00

40. 0

E 0-

C SC-5 a)

LLA-

W.0 C 09

4DP a) ZUi!s36p~-%.E 3O

Target: SnoN 6 inches on AsphaltDate: 2M18Time: 0905 - 1400)Water Equivalent (cmk. 2.6Snow Wetness m, (M.: L 0


U 300 RI- ~ 300 RR-700 RI

0 700 RR

Ci~m~m -1

0

-20

-4018 10 12 14 16 18

Frequency (GHz)

Figure 3-14 Spectral response of a' of snow 6 incheson asphalt.

40

Quarter is shown

DATE: 2/21/80

TIME: 1430-1600

TARGET: Asphalt

TYPE OF SET: Snow: 3-inch


WaterLayer Number Depth (cm) Density Equivalent Grain Size(From Ground) (To Layer Top) p(g/cmi) W(cm) (mm)

Overall 8-- 2.0 NA987654321 8 0.26 -- 0.5-1

TARGET CONDITIONS 6Height (cm): NA F - i 'Soil Moisture (0-5 cm): NA 4 _....._....__-.Temperature 0C: 2.0 I-i---I7-7--- 7.---Z-!17-- i(Ground)2 __

WEATHER OBSERVATIONS , ! _--~. o __ NOT MEASURED __ ___Air Temperature °C: 1.0 E O

Relative Humidity: 52%General:

Warm, clear . . . --4

SNOW WETNESS my_- 7LC-I 111....0-8 cm: 4.23%I' __ _ !

Air 60 40 20 0Depth (above ground level, cm)

TABLE 3-6

41

1* C

C) cm

OCC

C~C

C4 0-

'4-

0

-65a

LAIn

(U R4 83

C

-4c A

(ap) cp ju.9pilJJ90 6uIpe)AePS

42

Target: Snow 3 Inches on AsphaltDate: 2/21/80Time: 1430- 1600Water Equivalent (cm . 2.0Snow Wetness m,(%M: 4.2


U 300 RI300 RR700 RI

0 700 RR

~0

wC0

cn-20SM1== .oo oO

-30

-401II8 10 12 14 16 18

Frequency (GHz)

Figure 3-16 Spectral response of o of snow 3 incheson asphalt.

43

Figure 3-17 View of Test Site No. 3 with a traceof snow on 2/17/80.

44

DATE: 2/17/80

TIME: 1010-1340

TARGET: Asphalt See Figure 3-17

TYPE OF SET: Snow trace

LOCATION High School Parking LotSteamboat Springs, COTest Site #3

WaterLayer Number Depth (cm) Density Equivalent Grain Size(From Ground) (To Layer Top) p(g/cm3 ) W(cm) (mam)

Overall O-1 -- 0-1 NA98

7654321 0-1 --

TARGET CONDITIONS

Height (cm): NA j - l ---Soil Moisture (0-5 cm): NA 4 i ! - 132. 'Temperature °C: 1.3 -

(Ground) 2

WEATHER OBSERVATIONS 0 ---

Air Temperature °C: 0.8 0 0Relative Humidity: 96% ; -_---

General: -2 |' ";;; -..... T T . .. .. TT TTffiLight snow during data _- - -----.------ _.--.-_- ___

seno acuulto -4

SNOW WETNESS my_

Wet but not measurable ----- H -.due to sample size Air 60 40 20 0

Depth (above ground level, cm)

TABLE 3-7

45

-aC

- C

C *CD

0)6 )

0) o

In

(SP) 0D IUOI:zflJa8O: 6upj~es

0

0

-0 '4-0

E 0

C CD 'I.

LJJ a) )

C" CD CDC 0

CMC

IL-Cl CD C(SP)00 U?13)Po) BUOUh

46L

Target: Snow Trace on AsphaltDate: 2Ail@oTime: 1010 -1340Water Equivalent (cmh. 0 -1Snow Wetness m,(%M: -

Angle of

10 -I ncidence Polarization- u300 RI- ~ 300 RR

700 RI0 -700 RR

cb

0

C -20

-30

-4018 10 12 14 16 18

Frequency (GHz)

Figure 3-19 Spectral response of co of snow-traceon asphalt.

47

3.2.2.2 Concrete

As a result of the uncooperative weather conditions and because

no large concrete areas were available near Steamboat Springs, Colo-

rado, the measurements of snow over concrete with circular polariza-

tion were not obtained. In lieu of these measurements, analyses in

Section 3.3 will show the levels that would be expected from snow-

covered concrete. The levels were determined from linear and cir-

cular measurements of bare (non-snow-covered) targets and from linear

polarization measurements of snow-covered concrete.

3.2.3 Ice and Snow

In this target category, two data sets were obtained.

Lake-ice was observed at Shadow Mountain Lake, located in the

Arapaho National Forest in Colorado (Figure 3-1d). The MAS system

overlooked the lake from the Green Ridge Road. Figure 3-20 shows

the overall area. The open-water area is outside the MAS observation

range as shown in the diagram of Figure 3-21. Because of the distance

to the lake from the road, it was not possible to obtain 00 (nadir)

data and the 100 data, although given, may be biased by the edge of

the shore. Figures 3-22 and 3-23 present the angular and spectral

responses of ao and the ground-truth data are given in Table 3-8.

Since the resolution cell of the MAS radar issmall with respect

to a parking lot and since both cars and snowpiles are not area-extensive

targets, the concept of a° is not really valid. Using the standard

method (for the MAS systems) of data-taking does not yield a valid result.

For this reason, a snowpile was built in the Steamboat Springs High School

parking lot (Figure 3-24) and the radar was operated in a scan mode across

the snowpile and a car.

The scans were obtained by setting the MAS system to a specific

angle, polarization and frequency combination and then moving in

azimuth across the targets and parking lot while recording the received

power. These values were converted also to radar cross-section (RCS) a.

Figures 3-25 a, b, and c give examples of the scan data for 10.2 GHz and

RL polarization at three angles of incidence: 00, 100, and 700. Received

power is plotted on the vertical axis while the horizontal axis is in

relative distance along the ground.

48

Figure 3-20 Overall view of Test Site No. 4 showing thesnow-covered lake-ice on 2/27/80 with openwater seen in the background.

49

400%

CnlG!e Ridge Road Radar Trucks

Figure 3-21 Shadow Mountafi Lake rest SI.

50

DATE: 2/27/80

TIME: 0900-1300

TARGET: Lake Ice

TYPE OF SET: Ice

LOCATION: Shadow Mountain DamGrand Lake, COTest Site #4

Ice thickness approximately40 cm.

WaterLayer Number Depth (cm) Density Equivalent Grain Size(From Ground) (To Layer Top) p(g/cm3) W(cm) (mm)

Overall 20 -- 5.5 NA98765432 20 .25 3.75 --1 5 .35 1.75 --

TARGET CONDITIONS

Height (cm): NA . . .... _ _

Soil Moisture (0-5 cm): NA 10' - . .-_ __ ....Temperature *C: Not Measured -- --- '

(Ice Surface) ----- - - _ ---

WEATHER OBSERVATIONS __.... _ .... . __

Air Temperature .C: 0 _ ___ ___

Relative Humidity: NotMeasured . ___ _ .... __..General:

Clear, warming throughthe data set -10 .. IN-----_-- - "_-_

SNOW WETNESS m_ - _.-

0-2 cm: 0.34%

5-10 cm: 0900 1000 1100 1200 1300

TABLE 3-8

51

C. C

rD co

C 0D

CD D CDJ

CMC

(SP)00 ppljj wljat0

.. w ' 4cdj~

>0

L.~4D.

E K

Ii 52

Target: Sngw on IceDate: V/27NTime: 0900 - 13)Water Equivalent (cm): 5.5Snow Wetness m. (): 0. 3

Angle of

10- Incidence Polarization300 RL300 RR

"-700 RL0 ---- 4 700 RR

10

S_-20 "

-30 -

-40 , ,8 10 12 14 16 18

Frequency (GHz)

Figure 3-23 Spectral response of ao of snow on ice.

53

Figure 3-24 View of the snowpile and the car observedon 2/17/80.

54

777

0C o

7~ T- C -

4-01 4-

c) I- 0 (1L* :1-

00 0

4 - 4-

4). '

(u +

LII, tU

0.11

7 _ j 0_4

po to

55

The results of all the scans in both relative received power and a units

are given in Appendix B.

At nadir, Figure 3-25a shows that the asphalt backscatter is higher

in level than that of the car because of the convex curvature of the

car-roof. At the higher angles of incidence (Figure 3-25b and c), the

backscatter from the smooth asphalt surface is substantially lower than

that obtained from the car or the snowpile. The Luneber Lens (LL) also was

placed along the scan-line to provide a reference radar cross-section at 30' and 70'

If the peak values of the backscatter from the car and snowpile are con-

verted to numbers using the standard calibration routine, the angular and spectral

responses may be found. Figures 3-26 and 3-27 illustrate these responses.

3.3 Analyses of Snowcover Effects

3.3.1 Linear and Circular Polarization Backscatter Relationship

The understanding of the relationship between linear and circular

polarization backscatter coefficients is valuable for several reasons.

First, it would allow usage of the much larger volume of linear

polarization data to be applied to circular polarization data bases.

Secondly, it would improve our basic understanding of the backscatter

mechanism, although this effort will require additional work.

Linear polarization data were obtained for Sandia Laboratories

[4,5] in 1978. Figures 3-28 to 3-30 illustrate the backscatter coef-

ficient data for linear and circular polarizations at two frequencies

for three targets: concrete, asphalt, and short grass. From these

curves, the indication is that for very smooth surfaces, concrete

and asphalt at 8.6 GHz, the differences between circular and linear

are small, while for the rougher surfaceS, circular is generally a

few dB below the linear data. This observation, however, will be

shown to be a minor consideration for the case of snowcover on concrete.

Figure 3-31 illustrates the repeatability for system measurements

between the first report [1] and data presented in this report. The oo

agreement is seen to be very good.

56

DATE: 2/17/80

TIME: 1400-1600

TARGET: Snowpile

LOCATION: High School Parking LotSteamboat Springs, COTest Site #3

The snowpile was made from wet snow. It was approximately0.9 m high and 1.2 m in diameter. For other pertinentground-truth data, see Table 3-7.

TABLE 3-9

57

00

I-I

EL /e ix

.a 4w 06L

CoCLA 4^

LS.-

ooo

EC%J _

P). 0O1.1iiaY UJ:e)

... 58

Target: Snowpile on AsphaltDate: 2/21/80Time: 1400 - 1600Water Equivalent (cm): -Snow Wetness m,(%M: 0. 3


300 RL300 R R700 RL

0 700 R R

CO,

0

'-1

.-

0

0

0)

8 10 12 14 16 18Frequency (GHz)

Figure 3-27 Spectral response of oo of snowpile on asphalt.

59

*CD

(D 0

00 r

0 pu,

- 1-

0

CC

00 0

cc

U

600

0 00

-.a)

LA-.

C=

U' 0)

'4--

Iv CDJa

(SP C) ICDD110 5uJeeL),

CC

L- 0.

CDC

0 Un00

P.1 r-

oD CD 4

e~gen(a P). OC)lqgo6la~~

I~i r61

o f 00

r 3

A. 0

100

C 00

OCL

0S

ro

ad C~Cin0

CCo

__

ECD

= -Irm

CD,4< L

CD CD CD CD C

(a) P) OPjaioo uile

I6

30 Target: Asphalt

Frequency: 17. 0 GHzPolarization: RL

20 - 2/17/80- 8/16/79

-c= 10

,-

0

,-10

S-20

-30

-400 10 20 30 40 50 60 70 80

Angle of Incidence (Degrees)

Figure 3-31 Comparison of data reported in reference [1] with the data

obtained for this report.

63

3.3.2 Effects of Snow on the Backscatter Response of Grass

From the three data sets obtained on snow-covered grass, the

smoothed angular responses of ao with RL polarization are shown in

Figure 3-33 at two frequencies. These results indicate that, depending

upon snow conditions, the backscatter coefficient may be either higher

or lower than the grass in the absence of snow.

The two dominant snow parameters affecting the microwave back-

scatter properties are water equivalent and snow wetness [6,7]. The

effect of increasing snowcover (water equivalent) at angles away from

nadir is to increase the backscatter [7]. The effect of snow wetness

is to decrease the backscatter at angles away from nadir. The behavior

near nadir to changes in either water equivalent or wetness is not

as well-understood but may be dominated by the contribution from the

underlying terrain.

Observing Figure 3-32, one notes that the data obtained on 2/14/80

is on fairly dry snow, mv = 1.4% in the surface layer, while the internal

snowpack was dry. In this case, the effects of W and my appear almost0

to cancel with the o curve being slightly above the bare-grass case.

Two days later, on 2/16/80, the complete snowpack was wet and the

surface was very wet (mv = 5.2%). The o° response at angles of incidence

above 100 is seen to be much lower than the bare grass. This effect

results from the radar response being dominated by the smooth, wet

snow surface. The attenuation for snow of this wetness is very large

and therefore only the surface layers affect the o° response. If dry

snow had been observed, its o0 response would have been higher than

the curves of 2/14/80.

3.3.3 Effects of Snow on the Backscatter Response of Asphalt and Concrete

The four data-sets obtained over asphalt are illustrated in smoothed

form in Figure 3-33 at two frequencies. Again, the parameters W and mvare the dominant snow effects. These curves, in comparison with those of

Figure 3-32, seem very different; however, the differences may be explained

by reviewing the general situation of snow over terrain.

The backscatter coefficient for snow-covered terrain may have contri-

butions from both snow and the underlying terrain. The snow has two effects:

64

0

L- 1 )LL..

CD CD CD CD C C

>IIE=-~ IIt e

Of. /04V-.4 /-4&

4A Od r-Z/: C' %4

0A

400

0 0 0 0 0 0Ile

(gp 0 IUi~JJO3 u~apeS 00a

(9p) 0 lul:)Ijao: Bulqu-'

65U

CD

C)D

fL..

rLrJ

CC

I CC0

-(A

C > C ) C D D= 1C C D EC MJ - C '% j Y0

(9p) ofi 1uampJJoo 6uip:eoS 4--

00 CDC%J

N r C) Q0

CDL~ 3:

C% CCD - /'

4-

iii CD0 ' a -.LL. CLI / v.o

ooi C) 1 C)D CD CD(9P) .0 luapJaooo 6upafle:S

66

(1) The snow has an attenuating effect upon the radar

backscatter from the terrain, and

(2) the snow also contributes directly to the backscatter.

As a result of (1), since the backscatter coefficient for grass is greater

than that of asphalt, for equivalent conditions the backscatter from snow-

covered grass is affected more by the grass than the backscatter from

snow-covered asphalt is affected by the asphalt.

As little as W = 2.6 cm of snow on 2/22/80 is observed to raise o

significantly over the trace-of-snow case, even though there was some

snow wetness. Both of the other dates (2/15/80 and 2/21/80) on very

wet snow (4.2 and 3.8%) show similar responses for drastically dis-

similar values of W (15.7 versus 2.0 cm) indicating that the snow is

dominating the backscatter at high wetness values and therefore the

penetration depth must be less than W = 2.0 cm for these wetness levels.

The effects of snow on both asphalt and concrete on linearly

polarized backscatter coefficients have been measured previously [4,5].

Figures 3-34 and 3-35 present wet and dry snow responses along with bare

asphalt and concrete. In Figure 3-34, similar behavior to Figure 3-33

on asphalt is observed. The snow is seen to have a much greater effect

on the backscatter from the "smoother" concrete surface. When the curves

for snow on asphalt and concrete are combined in Figure 3-36, it is noted

that, for these smooth targets, the backscatter with snowcover is approxi-

mately the same regardless of the target. This fact indicates that the

snow is the dominant scatter mechanism and that for water equivalents

greater than about W = 2 cm, the backscatter from snow-covered concrete

and snow-covered asphalt is approximately the same. Similar trends also

would be expected for circularly polarized data, therefore the levels for

snow-covered asphalt given in Figure 3-33 will be comparable to the

levels that would be observed on concrete.

67 I1

or 0

CD a

1 1

LA..

Lr% CD4-)1D CPG; Uj00r

0 c

0e d % a) 4-

0

(U

CD 400-

Nc 0

L.

In

(9p 4.-.831OO6 IJ7

CL0 ~ ~ 68

co~

CDVCDJ

cL

:3i

L- C>

-~ -4-)I-OC

m 4-)

CD. -4 4.0

CI 4D I t- N

(8. adIO!1935UJf~

600

U- L

~ 00

(SP 00l.11imBlv

= - o69

7 00

C)

CD CD C ) D C

(9p IP 811180

.4 C~j a C4 )

coc7;Z3 0

%A

0 0 90 0 40 S.-

700

3.3.4 Ice and Snow

The data set over lake-ice (Figure 3-22) was taken with a 20-centi-

meter snowcover. No other circularly polarized dataare available on

snow-covered lake-ice (smooth ice), therefore, a comparison with the

HH-polarized results of Onstott [8] is shown in Figure 3-37. These

data sets on bare and snow-covered ice were obtained in the arctic.

It is observed that the levels of a of the snow-covered ice are within

about 3 dB of each other. The exact behavior of the snow-covered ice

may have been affected slightly by a low-level salinity, since thislake was close to the ocean. Noting the much lower level for the

non-snow-covered ice indicates, as for the road-like surfaces, that

the contribution of the backscatter from the snow probably is thedominant factor.

Pack-ice data, as previously stated, was not obtained. In lieu

of this data, the closest target found was a sea-ice pressure-ridge.

This ridge was 0.9 m high and consisted of 10-cm-thick blocks of ice

(Onstott [8]). Figure 3-38 presents the o data for this target.

The parking-lot data (Figure 3-26) is replotted with theaddition of the asphalt background in Figure 3-39. The values of o0

calculated for the car and the snowpile can then be compared with thelevel of the parking lot. The interpretation of this information

requires knowledge of the sensor's resolution cell and the purpose of

the measurement. If the resolution cell is large, then integrated

effects of cars, snowpiles and asphalt will be observed. Spatial

averaging of the areas of each target multiplied by their respective

oa values would then give an effective "ao" for the whole parking lot.On the other hand, if the resolution cell is small, then direct compa-

risons may be made (Figure 3-39).

71

hO0000

4-

N7 Z00

gL 0

U T~C~) S.a)ea

C'%JG

cf-0o 0 0 0 43

~ C'~I. 0

0000

.00 0Egt 00~ n

~~aE 4-+-e

0

/u Ir -

LL -~ CCD

(9p) ,oo IU.a!)jjgo:) 6u!ja:eOS

72

00

-t

00

o3 L-J

00

LA. 4-

d)

C~J0

-

-4

0

C CD

too

0 L

CD C L

en cm

(GP) p JUBl:)jjm uljqqea-

730

CVJ 00

LM W

(D / C/L I.N 0

L. -

cm 4= CDC

C%j r- r- CID4

(SP) ofi luGPal~ltoo BUIJ:4e3S

LflL~- L..01

000

CZ) E

I A 4-'0 = 0

-, 7 - Izz 7I

Q pnoC

LLdon 0')

(SP) oD1PP.0C UM O

74

4.0 RECOMMENDATIONS

Based on the experience gained from the present study, the follow-

ing recommendations are proposed:

Circular Polarization: For the few cases where the same target

was measured by the same system for linearly polarized (HH or VV) and

circularly polarized (RL) antenna configurations, the results show

that the magnitude of o° is comparable, although not exactly the same,

for all three like-polarizations. Specifically, for concrete

(Figure 3-28), the o curves corresponding to the three polarizations

essentially are indistinguishable one from the other. Although some

differences in level are apparent between o0 of the different polari-

zations for asphalt (Figure 3-29) and grass (Figure 3-30), the volume

of the data are not a sufficient volume from which to draw general

conclusions. For cross-polarization, HV and RR (or LL), there is even

less data available for comparison. Since linearly polarized data is

much more available than circularly polarized data, it may be possible

to use the available linearly polarized data bases for estimating the

circularly polarized scattering coefficient of terrain types if a pro-

cedure can be established to relate o0 (RL) and ao(RR) to ao(HH),

ao(VV) and o0(HV). To this end, a two-task program is proposed:

(a) Using surface- and volume-scattering theoretical models,

to develop relationships between the circularly polarized

scattering coefficients and their linearly polarized

counterparts.

(b) To design and conduct careful experiments to measure o°(RL),0 (RR), o°(HH), ao(VV) and co(HV) using the same system for

three classes of terrain types: (1) smooth surfaces, such

as concrete and asphalt; (2) rough surfaces, such asplowed ground; and (3) volume scattering media, such as

snow and trees.

Using the data generated under Task (b), the validity of the models

of Task (a) may be evaluated and the process, it is hoped, will lead

to the desired relationships.

75

T0

Backscatter from Trees: The measured ao value of a tree canopy

represents the backscattered power integrated over the effective volume

of the canopy that contributes most of the return. Thus, it is dif-

ficult to ascertain (a) the relative significance of the contributions

by the various "layers" of the canopy and (b) the degree of penetra-

tion into the canopy volume. Without this type of information, it is

difficult to formiu'late realistic theoretical models for the backscatter

from tree canopies. It is therefore recommended that careful measure-

ments be made using a high range resolution system such as a short-

pulse radar or a wide-bandwidth FM-CW radar. By increasing the modu-

lation bandwidth of the MAS 8-18 system to 4 GHz, for example, a range

resolution of the order of 15 cm may be obtained in practice (compared

to a theoretical range-resolution of 7.5 cm). A record of the spectrum

analyzer display corresponds to the power return as a function of range.

Such a record provides information on the relative backscatter by scat-

tering range layers between the treetops and the underlying soil surface,

with a range resolution of approximately 15 cm. Detailed measurements

of this type, coupled with the standard measurements of co (which employ

spatial and frequency averaging to reduce signal-fading) would lead

to a better understanding of the backscatter differences between dif-

ferent types and/or conditions of trees and to the formulation of theo-

retical models based on a more sound foundation.

Backscatter from Snow: Based on the experimental observations

made in connection with this and other investigations [5-7] of the

radar backscatter from snow-covered terrain, it may be concluded that

the three major parameters governing o° are (a) the snow water equiva-

lent (which is related to the snow density and depth), (b) snow wetness

profile and (c) the backscattering behavior of the terrain with no snow-

cover. In lieu of acquiring large volumes of data to cover a wide range

of parameters (a) and (b) for each terrain-type of interest, it is

proposed that the models developed by the University of Kansas [6,7]

(although for linear polarization configurations) be used to generate

families of o° versus e curves (at frequencies of interest) correspond-

ing to various combinations of snow depth and wetness. Such an approach

76

is not an exact substitute for direct measurements of o°; it is felt

that the backscatter contribution of the snow layers and the attenuation

of the underlying ground contribution by the snow layer may be estimated

with acceptable accuracy from previous measurement programs [5-7] to

provide approximate, but useful, estimates of o° for snow-covered terrain

types of interest.

77

REFERENCES

[1] Wilson, E. A., D. R. Brunfeldt, F. T. Ulaby and J. C. Holtzman,"Circularly Polarized Measurements of Radar Backscatterfrom Terrain," RSL Technical Report 393-1, University ofKansas Center for Research, Inc., Lawrence, Kansas,February 1980.

[2] Stiles, W. H. and F. T. Ulaby, "Microwave Remote Sensing ofSnowpacks," RSL Technical Report 340-3, University ofKansas Center for Research, Inc., Lawrence, Kansas,October 1979.

[3] Leaf, C. F., "Free Water Content of Snowpack in Subalpine Areas,"Proc. of the Western Snow Conference, 1966.

[4] Stiles, W. H. and F. T. Ulaby, "Backscatter Response of Roadsand Roadside Surfaces," RSL Technical Report 377-1,University of Kansas Center for Research, Inc., Lawrence,Kansas, July 1978.

[5] Ulaby, F. T. and W. H. Stiles, "Backscatter Response of Snow-Covered Roads and Roadside Surfaces," RSL Technical Report377-2, University of Kansas Center for Research, Inc.,Lawrence, Kansas, May 1979.

[6] Stiles, William H. and Fawwaz T. Ulaby, "The Active and PassiveMicrowave Response to Snow Parameters: 1. Wetness,"Journal of Geophysical Research, Vol. 85, No. C2,pp. 1037-1044, February 20, 1980.

[7] Ulaby, Fawwaz T. and William H. Stiles, "The Active and PassiveMicrowave Response to Snow Parameters: 2. Water Equiva-lent of Dry Snow," Journal of Geophysical Research,Vol. 80, No. C2, pp. 1045-1049, February 20, 1980.

[8] Onstott, Robert G., G. J. Dome, C. V. Delker, J. E. Pateland R. K. Moore, "Radar Backscatter Study of Sea Ice,"RSL Technical Report 331-14, University of KansasCenter for Research, Inc., Lawrence, Kansas,December 1979.

78

APPENDIX A

RADAR BACKSCATTER COEFFICIENT co' DATA

-r 0 CA CD W. to0 cn 0 - '. 0 Rr 0 0 Mo 0l r- C%j -d q* CV LC) co 0) (%i r - LA) 0) N- CA CV 0co 6 0; Oi c6 0; c6 r- 0 t.0 '6 6 c6 '0 c LA LA 4

4A/ I I I I I I I I I

L5

r_ CV) Ln LA M.. M " W'. 40, M 41t C)- CDJ

-0 r- 4D '0 m2'0 L Coj .0 LA m- to "A en0 (a -t OD m. 0o - - -a - - - - - - - -

LAto0 CV)

00- LA r- I* CO -c - WoC ON Oh% tD OD Rr

t.,- o 0N 0O r-. P- a- co W- mA LA 4*- r-j tD 0n '. CD. '.0 C C~)3CL4 0

* '. ON LA N-j N-j r o C~) cn Ln 4a lA LA -o 0" ONa 0 'aLo -.. L'a 0 - I - r W ko mr - d M - - -l -0 -~ r' -

L&o 'D N- ('a ('a - C; N- 0; C6 LA C6- C C h 0

C I g - - - - - - - - - - - -- -

o an o m co *o w m C7 aO w CD -4 a l a Y M a

LA LA Co C A -1 LA a- W- %0 0 %0 Ca CD C, -0 w' 0; 0a LA C6 CO ('a - - LA LA L 'a L6o

on r LA M- - W~ to) C) LA) 0%D' A L

L)O A- Co a Co ( N- c; 'a Co LA L A LA w-

t= LA (l) ('a LA ('O rL LA LA C) 0o - -0 'a% 00 A LA

t. O C o ('a C)'a Co(' 0% ULA r- LO Co ('a CJ LA ' LA 0 j LA D

rn - a - -r n - 0- 0 - -l Clta a9 al a al a a- ai 11 a a a* ai 9 ai 9

LD LA C- Co LA N- - %0J nLA to LA to LA CDC aL

o ( -i a- cc - -0 e N - -i w ('a -i 0 C N -i Oh *-

CA-1

10

CDc n -~ m. Osj CV W 4 V C 0i

C3

0 a- -

*-I..I ...

tol CJ L Z

LU.

1- 1 i CJ C cli 04. C1 c'.j eC ej eI s)

*0 0j

C-> \0o

CI- C C U 9 9 l kLU > %DP n )c

LU Cs)l O

C');

w .- c ) U I ~ C1 C. , ~ U , U

0-

N. C\j LO C) 0 U-) -- 00 q. C)0

C00 m l C) J9 CJ C\ C) (\a C)J C C)J C%

S.- U-) CAo~ LO r 0) CC) to co tD(.D 0 LO CJ ,-. -l ON. eJ 01 c0j (W c -cr

N. 0~ N. i 0 c0 LA N A 01iL

S-

3LA ol

cc CJ

I-ci o~~ua %D qt LA U') C)i LA LA 01 C~j -l 41- C6-4 - 0 N. LA 01 N CO LA LA C9 01 LA 9A

L- 0D

o

0Co- - " 19 LA 01 ( *) 01 C" 0 A . 09

co - ~ - - r 00 - - m -nI I I I I I I

0 I

C-j ct: 0c Ix -i LA: 0i LAixN -Ix ex I I Ix I cc Ix I I

I-,-

01 0 C~ ~ %J ~ ) ~ J CO- N

0 fn m2 - 7 c 0 C ! 4

(a a~ 0% '0 V - ) CO) n (w) mA 0 W0

0 4m kD t S c n m

o CW CV) N~ CV) N~ CW, NI N C)

-,A - Z

0-

CM LL LLIW a~ C\J m 0 j 4 *4- LO LO co CA - .

cc0-L m N- c N N N

2*0 00

0m

LL0 * IU.. m O LO cV) N- (w) 00 to0 C0 .4t co

NL - ~ N~ 0i N NCJ

I-!7 CD LA! C9 L9 L9 - -9-

N~ -~ m r- Na Nc CN T ON -d O

C-)

o C;- N- 00 '-: N- 00 N co

-i - -i i cc -i - e -

LD LD LD tv to

LL C6

A-4

CD 0 . CO '- 9OO ~ 100J 10 ('4 O r 0) 10 00 r- CV) C) PN- ' '4 (4Q ~ t C\J ('4 e, 04 C.") ('4

m-ocr 0 4 ) O o C 7

0 .co co qc CD m 0 0r C) 10) C) 0 4D h0 a 41: kL;0C~ h 0 () 0 A 1

N. j (V) - ~ cl - l -~ -l ~ 10j I-j C~~ C

C)-o 0A O U)0 o c ~

a 0-- - c- ~

..- .. .. r" c LO LdA C) -d ON -10 CO) U

0C4 :* b 0 4 L A 0 cLA -6 q; C6 10 ('4 4 0' N

-o -o C4 o ('4 - O - - ('O - -

-U- s co N.r CO Rd- LA) 00 0D .- m' -C) LO

I-- I. 0 V 7 O CJ r ~ ) O o cL) kALA (' CO; C CO LA C. 0Co~

U") 414- - -4m -o o to - co m

CO Ln ('O co Lc) to LA w. LA C- N.0 co m (o 0* %0 0 10) %Q U' N, 44

- i , -i I= - w

(Y ' C to C9 CO 1 C L

a: CU- 0

10 ~ 0' ~('4 ' 10A-5

CL

CCD

CDo

C 0_ _ _ _

'0

o

I-D

0 0

LL. m

5-C)

0%

~ ~ ~ ~ A-6

A.-A092 077 KANSA UNIV/CENTER FOR RESEARCH INC LAWRENCE REMOTE --ETC FIG 17/9

CIRCULARLY POLARIZED MEASUREMENTS OF RADAR BACKSCATTE R FROM TER-_ETC(UI

jLL AR 11 A STILES, F T ULABT. E A w ILSON DAAK7078-C1121UNCLASSIFIED CRINC/RSLTR393-2 ETLO2 3 N*2 ffffffffffff

o~4 mr 0D CV) C. r. '0 M A 0

00 LA at w. 0 Go r= %0 . - 01 f-scMi cM C14 C%) (w) 0i CMj CMj C C14 CM CM

.4A C\J 40 .- 4D0 %D0 LC CMi Rt CV

-c - l (' 01 '.0 19- P-'0 LA 01 0! .

oCM M C C M C14 CMj CMi C4 cM CV

o 0 CI -O

X -( 0 - CO q CM . LA C9 (C) LA C') f-0 - 60 .1: ." . ."Cj .w .nc

CM- cMi CNJ CNJ CNJ CM cMi C%J

V) A cs) CO l -01C0 0 '0 C' . e

co01 4D LA) to0 01n LA LA C0 e- LA.5- 0

0 . LA) CO %0 CD %D0 CM m' ON LA) co C 010CMi - l C M cM CM CM- - M N4 9

LI.I

LA) co 0D ci 0 CMQ LA) to0 0) CMi Go a0 CM C'9 k91 - O - CM %90

Ua. m' La) .0 '0 01 LA Os ce) co LA) W. CMi '0LaJ CMi -Oki-CM - CM CMl - cv

LaJI,, a. cY) 0 CV) 00 co CV) c mOC)

I- Id, C C') (In 4D 0 a-. '.0 LC) Rd 01ltC)CM ' L C6 4 a- 01 LA u-r_ 1 :

C% C CM M - - - CM - -

al al I, a aaa

CCDI) - Cno .9t CD Ln C 0 1 00 01 .-

On C' LLA CM 0%) C)- r-. 0D cM CM

o- --. 0- 0O C)- 0N LA r- 01 C - LA 01

- - C - CM -i - - -i -e -) cc I= 1= ix Ix a z w a

o~~~t to0 0- to- . 1 0 0 - -C; CO LA Go 01j C')-. r- 0w - CM -_ - M - CM C -

aA-

ON 01 l) LC) Ln f'. C.j CIj ON LA ia..

kA CV) 40 WW LA t M rl V) %. i ~OWJ CJ CJ cmJ C14 C .l vCJ VIA C*. C% J l

rr) 01 CV() Go C~j WAL

C4~ C- (% - ' C%iJ a) Cli c C>J .

0. 00 .- 01 0 C14 4NI cn O co r- W).. I W 0 O (%.J Co 0 ~ ~ 0 L l ~ C

C~u~ -4 0 LA 0

(M-01 Lf l Cl %DU- cE0 C') L A L Cli 1* 01 0 ! CO AU- CV CV) LA ct. C LA LA qd) COi 9-l 0h C'Wj LLI 00.

C-)

IJ I

Cl r. LA 0 L 0* CD 0'i to LC) 0C-C)

0

- - -i -e a-CDI I= ox ae I= ae a a

o co co

A-8

co _ _ 1 L) r 4DGC)

C)

aJ * 0

8n fj - - 0 0-

w_ x -- - - -m c

I-oLu . D 0 1 09. 1~ - ( o C)s

0 ~ LL 0 co I *O *O

LL.%J C) (E ~~ f c; c; C (7 Lc;r ~.~ -- - I

-o 0~ cc) ccon toan ~ Cv) C .*

I-l

0l -z .. c; C J r- C

LL o r- C~- o ~ () CJi C) OE C) 0l Li)

Il Ir I= W I I II

L)C. CD__ -

LUC c-

I-C ~ c s ~ ~ 9- 0 t Ll o 0cc * . .

I- c so ~ c .~- so c-J 's A-9v

I

APPENDIX B

RADAR SNOWPILE SCAN MEASUREMENTS

The scan measurements were conducted at Test Site #3. (Steamboat

Springs High School parking lot). Two scales are given for each scan.

The relative values of received power are given along with the calcu-

lations of radar cross-section a. The radar cross-section a is related

to the radar backscatter coefficient by:

a= aG Ail l

where Aill is the illuminated area.

k ______--.-----.-

FH 405

03

0 4

5B-

I'm-(gap

.- ..

-.-~rvrr"1

?!~5~.i aIJFISo~M~eA&~ ~"a" ~ -

Py.

I

~iA~ 4O~

/0 -

as

05-----

-30

C dt

I C~v- -

-10 -~5..

-IS~ ~

----------------------------------------------------------

_

-- I

- B-2

I--L

-ga0

-05

-B-3

~4L. *11 I-

is-

010

-103

-4B-4

405

01

Y p~i~t,4rCar1~- Ft. -

-15" - _, :

10

B-5

-101

B-

-'5

-I0v

-B-

r)-

0B-

Rl ID

20-

-o

0B-9

-50

-40-

8-10

Leo 1.o ~Zoo

I5 -

40

- I'

-- ..

-0 .. . ...

B-11

5LC A - )d 4 PO pP,

F= 1~ zo

5-

I0-0

0-

-4o-

-1Fi

B-1 2

pr

FHa)~~/Hc

-20

~k~a~M~oo~ I~iy -13~

-F= Pv-

-20-

-50-

B-14

PV-

40-5

10.20Caa

Ft~i~Lto5 B-105

-FA 4J.

-0 -

- I

TH=qaS- 0 - .'

(cv

-/0 --------.Jj.

-30 - -

- I vI~4.fe:;E~

.. . ... . ".. I .. . . . .

B-16

4p4-

o -

Kl-~

01

-30

-~v

-2e-

-30

B-1

0

R~ I

-0 -o- -... ..

-zo

-- 4o

-- eo .... t,

B-18

caw±F = Ii I

/ /_ ,to-.-I,50 --

-20- Cox

-30

..-.. .. . .. .....

- '1B-19

0-

-20-2

RL0

p-ZO

-4--- -.- "-'--

• -zo -

-30-

BI_

--jr - - 21

17 - 15

-0A 5,RI2~.. i00 .

-to

-20 - 0'

B-22

4,t05

-20-

rp0

-20-

B-24

6w~oAkH~ P4Ju4i, LA.

FL

--- 0

-300

B-25-

-15

O-0

-330

- s o - IL -

B-26

-5teaAA -

-0

-40

-2SB-

-10

-4o-

-

B-28

• .515 .

RL A' O

-2o

-40-

-45.

96p

-8-2

-40.- 1

t

8-29

[- -' 0 -

-10 -

-30

-2 0 - -i /-40-

-30'

Cite~

B-30

P~PV.

-/00

-4o

-45-

B-31

-5 -30

-0

-330

-20

z ,-4o - / ......

-3oL -., ,

- -in 4S-> L

TI

B-32;5

RL

-3o"

-2o = -_ ._.!. ..

I Z

4, -

B-33

gA .2 1A A L A

- ,16.2 r

RR

0 30

-2.0-6-JO-

-Z S ..-. ....

-30

B-34 it

: ie

Ii i

B-34

A

...... .. ...... - w d

~I-- 30

-30

3 41

-2.0

-45

-30-

-4o-4k. e--, .

-- 35

-3 -4

1

B-35

-40m-'5

-30

-40-

-l,-3 -

B- ,w6i /-.",--

B -36

Pr-

4314

PB--

RoPv-

O -

-10 - -

-C420

446 -30

-2-0-

-40--306 -

IB- 38

5 CdAAR L64 'Pr V-lA r

-A5

4*,FM = Vl

-3030

-- 3

-lof

IA, F. -10

y? _. q.5 - -4o

-20" - '-

-4 -4-30 -

-- - -. . . .. r . .. ..

/0,2 1.t,-L. Cd-'.

2.p2.-. .;,iooA

--40

pwj:-M Lek

P-

Lc-,F9C 44 -0

-20

F$~ L~o-0

-330

B-4

poj ,s 2ft' l~o

Pr-

/1 0

41.2 --

-20

-- Za

-3,3

B-42

LAI

rb 43Z.-0 -

-30

-50.

-30-

LL

B-43

w - 1-5--

.4.0

-s

-3 -.---- 44

-40 -44

P#tai4~f~

P.-

04

-5

P-

-20

CA4viM 5 5Ca-

FI4=-II -

-20"

--. -

B-46

........ .....

Pr.-

L :,',. Fg 4.52. 5" .

-30

-Zo

-40

-35" -45-

4 i

B-47

60 R0lkU

-120

F1c fI 4 L44

-46

-30

B-48

L---.mmo

for research inc lawrence remote circularly … · 2014. 9. 27. · mohamed abdel-razik adnan aslam...

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