In-flight tests of airborne infrared scanners, and comparison with field reflectance dat

Fischer, W. A.

Friedman, J. D.

Sousa, T. M.

English

NASA Technical Reports Server

UNITED STATES 
DEPARTMENT OF THE INTERIOR - 
GEOLOGICAL SURVEY d7#-388Cj\ 
e h'&s& cR- bapdg 
CASE F I L E  I 
TECHNICAL LETTER NASA-5 
PRELIMINARY RESULTE; OF AERIAL INFRARED 
SURVEYS AT PISGAH CRATER, CALIFORNIA * 
by 
W. A. F i scher ,  J. D. Friedman a n d  
T. Me Sousa  
* Work performed under  NASA Con t r ac t  No. R-146 
https://ntrs.nasa.gov/search.jsp?R=19700029582 2020-03-11T22:53:02+00:00Z
UNITED STATES 
m P m N T  OF THE INTERIOR 
GEOMGICAL SURVEY 
Technical Let ter  
NASA - 5 
A p r i l  22, 1965 
Dr .  Peter  C.  Badgley 
Chief, Advanced Missions 
Manned Space Science Division 
NASA Headquarters 
Washington, Do C. 20546 
Dear Peter: 
Transmitted herewith a re  'Qp copies of: 
TECHNICAL LETTER NASA-5 
PmLIMINARY RESULTS OF AERIAL INFRARED 
SURVEYS AT PISGAR C R A ~ ~ E R ~  CALIFORNIA .* 
W, A, Fischer ** 
J. D. ~siedman* 
+% T o  M. Sousa 
Sincerely yours, 
Re M, Moxham 
Chief 
-k Work performed under Branch of Theoretical Geophysics 
NASA Contract NO, R-146 
+% U, S, Geological Survey, Washington, D*C. 
DISTRIBTPTION LIST 
NASA Office of Grants and Research Contracts Division 
Attention: Miss Winnie M. Morgan, Technical Reports Officer 
Dr. Peter  C ,  Badgley 
Chief, Advanced Missions 
Manned Space Science Division 
NASA Headquarters 
U. S, Geological Survey 
Copies 
25 
UNmED STATES 
DDARZFMENT OF THE IMTERIOR Technical Letter 
GEOLOGICAL SURW u - 5  
April  22, 1965 
SURVEYS AT PISGAH CRRTER, CALIFORNIA * 
*% 3536 .3c)c 
W, A, Fischer, J. D. Friedman, and T, Me Sousa 
I n i t i a l  surveys u t i l i z ing  the  NASA remote sensing a i r c r a f t  were under- 
taken from February 9 t o  February 17, 1965, a t  Pisgah Crater, San 
Bernardino County, California, Sensors aboard the  a i r c r a f t  u t i l i zed  
i n  these surveys included a Reconofax 4 infrared scanner operating i n  
the  8-19 part  of the  spectrum, and a AAS-5 scanner f i l t e r e d  so as t o  
record energy i n  t h e  4.5-5.5~ part  of the  spectruaa. 
Pisgah Crater nibble cone and adjoining lava flows ( f igs ,  l,2, and 3) 
were selected as t h e  s i t e  of the  i n i t i a l  surveys f o r  the  f ~ l l o w i n g  
reasons : 
1) The rocks a r e  re la t ive ly  f resh  and largely unaffected by 
weat hering. 
2) The area i s  largely devaid of vegetation. 
3) Rocks having similar chemical composition occur here i n  a 
variety of physical conditions (rough and smooth surfaces, consolidated 
and loose). 
4) The area i s  f ree  of snow f o r  most of the  year. 
5) The area i s  readily accessible by land and a i r .  
X 
.++xW~rk performed under NASA Contract Ro. R-146 
U. S, Geol.ogi.cal Survey, Washington, D, C, OFFICIAL USE ONZY 
6 )  Geologic maps of the  area are  available, 
7) Support f a c i l i t i e s ,  such a s  photographic laboratories, a re  
available a t  nearby NASA ins ta l la t ions ,  
The pr incipal  objectives of the  i n i t i a l  surveys were tes t ing  t h e  
airborne and related f i e l d  monitoring equipment under operational 
conditions and developing f i e l d  methods f o r  describing the  fiurface 
of various rock un i t s  i n  a s t a t i s t i c a l l y  val id  &mer  and i n  terms 
meaningful t o  t h e  interpretat ion of the  infrared records. 
The i n i t i a l  surveys and related f i e l d  studies have a lso  contributed 
t o  several long-range objectives of our program by permitting: 
1)  an assessment of the  value of infrared records i n  measuring 
tke  differences i n  t h e m l - i n e r t i a  of various ear th  materials and 
relat ing these observa%ions and measurements t o  differences i n  consoli- 
dation and surface i r regular i ty  of the  various materials; 
2) an assessment of the  e f fec ts  of different  angles of view on 
infrared records and relat ing these observations t o  surface 
irregulari%y; 
3) an assessmeat of the  geologic value of simultaneous observations 
of solar  absorption and infrared emission; 
4) a preliminary assessment of the  geologic value of observations 
of the  speetral  dis t r ibut ion of infrared energy emitted by various 
rock types present i n  the  area; and 
5) a preliminary appraisal  of the  e f fec ts  of a l t i t ude  on 
infrared records, 
OFFICIAL USE OELY 
In  preparation f o r  t he  remote-sensing surveys, a e r i a l  photographs 
were taken a t  a scale of 1:4000-1:8O00, control  points were established 
and targeted, and topographic prof i les  of selected areas were compiled 
a t  scales  of 1: 600, The targeted control  points were used i n  t he  
preparation of the  topographic prof i les  and w i l l  be of addi t ional  
value i n  cal ibrat ing the  various sensing instruments and i n  r e l a t i ng  
various remote- sensing images t o  one another, 
During the  period of a i r c r a f i  f l i gh t ,  t h e  temperature of each 
of t h e  major rock u n i t s  was recorded (seven gross l i thologic  un i t s  
were studied i n  t h e  Pisgah area) , These un i t s  were: 
1 )  aa, rough- surfaced o r  granular basa l t i c  lava; 
2)  pahoehoe, basa l t i c  lava having a re la t ive ly  smooth o r  
vesicular surface; 
3) desert pavement mosaic of basa l t  fragments and areas 
covered with loose fragments of basa l t i c  lava; 
4) cinders, blocks, and ash of rubble cone; 
5) s u r f i c i a l  materials, chief ly  calcareous s i l t  and quartz sand; 
6) a l luvial- fan material  ranging from s i l t  t o  boulders, of 
diverse composition; and 
7) playa deposits, mostly si l t  and clay, 
These mits ( f igs ,  3, 4, and 5) were monitored t o  provide ca l ib ra t ion  f o r  
the  a e r i a l  infrared images and basic information re la t ing  t o  t he  thermal 
properties of the  rock m i t s  themselves, These measurements demonstrate 
t h a t  t he  various v-nits d i f f e r  from one another i n  thermal properties.  
3 OFFICIAL USE ONLY 
Cinders, f o r  example, a r e  characterized by low radiant temperature 
during night-time hours; a rapid r a t e  of change i n  temperature a t  dawn, 
signifying low thermal iner t ia ;  and re la t ive ly  high radiant temperature 
i n  daylight hours, These charac te r i s t ics  contrast  strongly with 
charac te r i s t ics  of aa and pahoehoe lavas, which have lower r a t e s  of 
change and radiant temperatures more nearly approaching the  temperature 
of the  air surrounding then, Close examination of t he  temperature 
records suggests t h a t  each of the  un i t s  i s  distinguishable and possibly 
iden t i f iab le  by analysis of i t s  thermal behavior, 
The radiant temperatures of each of these u n i t s  were recorded 
several  times an a e r i a l  in f ra red  images during t h e  period of time 
represented i n  f igure  4. Although only preliminary analyses of these 
records have been made, these analyses suggest t h a t  t he  thermal 
properties of the  various un i t s  may be deduced from sequential airborne 
infrared images, provided appropriate thermal reference i s  available 
from ground cantrol  o r  possibly from an instrument cal ibrat ion system, 
Some preliminary r e su l t s  of t h e  analysis  of the  airborne infrared 
records a r e  a l so  shown i n  f igure  4, 
I n  addit ion t o  monitoring t h e  temperatures of various un i t s  during 
periods of a i r c r a f t  f l i gh t s ,  measurements were made and samples 
col lected t o  provide data relevant t o  other parameters which may 
affect  t he  way i n  which various surfaces a re  regis tered on-infrared 
images, Prof i les  of segments of t he  surface were among the  data obtained 
i n  t he  f i e ld ,  These prof i les  were measured i n  two directions a t  a 
2 
spacing of 4 feet i n  a rectangular g r i d  system of 236 ft .  f o r  each 
4 OFFICIAL USE ONLY 
l i thologic  uni t  ( f ig ,  6) .  To date, estimates of the surface i r regular i ty  
o r  ~nicrorel ief  were made f o r  each sample location i n  f ive  li'thologic uni t s  
by measurement of the profi le  surface length ( f igs .  7 and 8) and estimation 
of the  t o t a l  surface area. The r a t i o  of surface area of sample t o  the  
area of an equidimensional plane i s  considered here an index of surface 
i r regular i ty .  The mean surface i r regular i ty  of 16 samples of each 
lithology was plot ted against change i n  infrared image density per 
degree of arc  (fig.  9 )  t o  determine the  relationship between surface 
i r regular i ty  and image density, 
These relationships suggest that ,  i n  general, t he  t o t a l  radiating 
surface, and hence the  t ~ t a l  energy vis ible  t o  the  detector a t  any 
one instant  of time, diminishes more rapidly f o r  i r regular  surfaces 
than f o r  re la t ive ly  smooth surfaces with increasingly oblique angles 
of view* 
To evaluate possible geologic significance of observations of 
the  relationship be-bween solar  absorption and infrared emission, the  
film density of the  infrared images of the various uni t s  was contrasted 
with t h e i r  absorption of vis ible  l igh t  as  determined by colorimetric 
measurement ( f i g ,  10) , The preliminary resu l t s  of t h i s  investigation 
a r e  shown i n  figure 11, These observations show tha t  the  unconsolidated 
deposits, cinders and si l t ,  emit significan%ly more infrared energy when 
exposed t o  sunlight than the  consolidated lavas, although the  cinders 
and s i l t  re f lec t  more (absorb less )  solar  energy than the  lavas, The 
data likewise suggest t ha t  t he  i r regular ly surfaced aa ( f i g p  10) emits 
more radiation relat ive t o  Its absorption of solar energy than the  
somewhat l e s s  i r regular ly surfaced pahoehoe, 
5 OFFICIAL USE ONLY 
Sensor f l i g h t s  were undertaken at  a l t i t u d e s  of 1,500 f e e t  and 5,000 
fee t  above t e r r a i n  t o  obtain preliminary data re la t ing  t o  t h e  e f f e c t s  of 
increasing a l t i t u d e  on our a b i l i t y  t o  dis t inguish various materials ,  
A t  present these  images a r e  unevaluated; they  w i l l  be s tudied t o  determine 
t h e  e f f ec t s  of successively higher f l i g h t  a l t i t udes .  
The spec t r a l  d i s t r i bu t i on  of emitted in f ra red  energy i n  t h e  5 - 1 5 ~  
range was measured i n  t h e  f i e l d  with a spectrometer-interferometer 
(fig. 12). Strong s igna l s  and c l ea r  records were obtained t h a t  seemingly 
show s ign i f ican t  differences i n  t h e  spec t ra l  d i s t r i bu t i on  of energy 
emitted by t h e  various l i thologies .  The recorded s ignals  a r e  being 
processed by a co-adder, computer, and wave analyzer, t o  determine 
which of t h e  processing instruments and techniques y i e ld  t h e  most 
meaningful r e s u l t s  . 
SUMMARY OF INFRAmD SURVEYS 
Pisgah Crater  and adjoining lava flows, California,  were se lected 
f o r  t h e  i n i t i a l  surveys undertaken with t he  NASA remote sensing a i r c r a f t .  
These surveys were primarily intended t o  t e s t  equipment under f i e l d  
conditions and t o  provide in f ra red  imagery of t h e  t e s t  s i t e  a t  various 
times of  day and from various s p a t i a l  posit ions.  F ie ld  control  
s t a t i ons  were surveyed and targeted on t h e  surface of t h e  t e s t  s i t e  
t o  f a c i l i t a t e  development of topographic p ro f i l e s  at a sca le  of 1: 600 
and t o  a s s i s t  i n  r e l a t i ng  various sensor records t o  one another, 
FOR OFFICIAL USE ONLY 
Field measurements of surf ace temperatures, microrelief, and 
laboratory measurements of reflectance were contrasted with measurements 
of fi lm density on infrared images acquired a t  various times of day, 
Measurements of microrelief were also contrasted with fi lm densi t ies  
of various materials imaged a t  increasingly oblique angles, 
Contrast of these various functions suggests t h a t  unconsolidated 
materials possess a lower thermal ine r t i a  than consolidated materials, 
tha t  unconsolidated materials emit larger  quantit ies of infrared energy 
than consolidated materials when both a re  subjected t o  similar quantit ies 
of solar  radiation, and tha t  t he  fi lm densities with which objects a r e  
recorded on infrared imagery d i f f e r  with angle of view; commonly t h e  
differences a re  greater  f o r  rough surface than f o r  smooth. These studies 
a l so  suggest t ha t  these re la t ive  quantit ies and changes i n  relat ive 
quantit ies of radiation may be observed f rom airborne platforms. 
O F F I C I A L  USE ONLY 
ILLUSTRATIONS 
Figure 1, Index map showing the location of Pisgah Crater area, 
2 ,  Index a e r i a l  view of Pisgah Crater area, Large rectangles a re  
fundamental t e s t  s i t e .  Small squares 1- 5 are  special-purpose sadar 
s i t e s ,  Basaltic lava flows of Pisgah Crater a re  larger  dark areas 
t o  the  north; flows of Sunshine Crater a re  t o  the south, Salient 
geologic features include : A) Pisgah Crater, B) Sunshine Crater, 
C )  bisected Lavic Crater ( a l l  pyroclastic cones), D) aa-textured 
flows, E) pahoehoe-textured flows, F) tona l  differences indicating 
compositional and age differences i n  Sunshine flows, G )  Pisgah 
f a u l t  scarp, H) Lavic Lake playa, I) basalt  fragments near southern 
end of Pisgah flows, overlying mud-cracked s i l t y  clay surface of 
playa, J) pepper-salt pattern indicating presence of s i l t  pickets 
i n  surface of basal t  flow, K) Sunshine Peak Range composed mostly 
of Tert iary andesite and dacite porphyry and lesser  amounts of 
Tert iary andesite dikes and Mesozoic quartz monzonite, L) older 
Quaternary alluvium, and M) Recent fan deposits, 
3. Aerial photograph of Pisgah Crater showing areas and l i thologic  uni t s  
whose radiant temperatures were measured during a i r c r a f t  f l i gh t  sf  
4 Chart showing radiant temperatures of various materials during the 
period 0600 $0 0800, February 13, 1965, together with the  temperature 
of the air  and sky and other meteorological parameters. Underscored 
numerals indicate fi lm density values of infrared images of various 
material, The materials t o  which they refer  and the  time the images 
were produced are  shown with lxS s ,  Density values not t o  scale, 
Based on preliminary interpretat ion of data, 
OFF JCIAL USE ONLY, 
Figure 5, Monitoring a thermistor array system t o  determine ground temperatures 
during infrared a e r i a l  survey of Pisgab Crater area, February 
12-14, 1965- 
Taping 16 x 16 f t .  sampling grid, to ta l ing  236 f t m 2  t o  obtain prelim- 
inary hand specimens of Pahoehoe surface material f o r  laboratory 
study* 
Sections selected f o r  each li thology are  those most closely 
approxidt ing the mean surface area of a l l  samples f o r  each lithology, 
Angular, vesicular basal t  fragments dis t r ibuted i n  rough polygonal 
patterns on mud-cracked calcareous s i l t y ~ c l a y  surface of Lavic 
Lake playa, 
Range i n  change of image density away from centerline of image of 
several l i thologies,  plotted against surface i r regular i ty  ( r a t i o  
of mean surface area of approximately 16 samples of each li thology 
t o  area of an equidimensional plane), Iktermined from selected 
infrared images flown February 13-14, 1965, and preliminary 
interpretat ion of data, 
Reflectance of l i thologic  uni t s  i n  the v is ib le  spec$rwn, 
Relationship of the reflectance of various materials t o  re la t ive  
infrared emission, 
Interferometer spectrometer used f o r  f i e l d  measurement of t h e  spec t ra l  
energy dis t r ibut ion of infrared radiation ( 5-15p) emitted from 
various rock surfaces, 
OFFICIAL USE ONLY. 
INDEX M A P  S H O W I N G  THE L O C A T I O N  
O F  THE P I S G A H  CRATER AREA, CAL IFORNIA  
( T I Y E )  RELATIVE ~ U U I  D I T Y  
PASSOVER OF PLANE 
2 0  
- ./--- I 
3 
/ 
W I N D  6-8 MPH ME 
AIR TEMPERATURE ( I t i  SUN) 
SKY TEMPERATURE 
0 6 0 4  0 6 3 0  0 7 0 0  0 7 3 0  0 8 0 0  
T I M E  
= I I N C H  
(P-I, l C )  
T Y P I C A L  PAHOEHOE S U R F A C E  
L- - 
' I I N C H  
_I 
I 
T Y P I C A L  aa S U R F A C E  
I ( P - 6 , I A )  
T Y P I C A L  V O L C A N I C  E J E C T A  S U R F A C E  
, 
E - W  E-W 
T Y P  T Y P I C A L  F R A G M E N T S  ON PLAYA SURFACE 
CHANeE OF I M I e E  DENSITY 
I N  RELATION TO SURFACE IRREGULARITY 
3 3 0 0  
V) 
I l C I N D E R S  
aa  1 1 
@ BASALT F R A G M E N T S  ON PLAYA 
a 
(IN BASALT POCKET) cA!-cAREOus' 
S ILTY CLAY 
u ... I 
/-- ..* 
W 
U 1.40 
4 LL 
a 
3 
. . + <(PLAYA SURFACE) 
B A S A L T  FLOW ( H O . 2 )  
-  PAHO HOE HOE 
M
+ PLAYA S I L T Y  C L A Y  
0 
400 500 600 700 
WAVELENGTH ( M I L L I M I C R O N S )  
07 1.00 0 .01 .02 .03 .04 .05 .06 .07 .08 .09 
CHANGE I N  IMAGE DENSITY PER DEGREE O F  ARC 
PE
R
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EN
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R
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TA
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0
 
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Preliminary results of aerial infrared surveys at Pisgah Crater, California

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