Imagery from three successful ERTS-1 passes over the Delaware Bay and Atlantic Coastal Region have been evaluated to determine visibility of aquatic features. Data gathered from ground truth teams before and during the overflights, in conjunction with aerial photographs taken at various altitudes, were used to interpret the imagery. The overpasses took place on August 16, October 10, 1972, and January 26, 1973, with cloud cover ranging from about zero to twenty percent. (I.D. Nos. 1024-15073, 1079-15133, and 1187-15140). Visual inspection, density slicing and multispectral analysis of the imagery revealed strong suspended sediment patterns and several distinct types of aquatic interfaces or frontal systems

Klemas, V.

Otley, M.

Srna, R.

Treasure, W.

English

NASA Technical Reports Server

Paper M 3 
APPLICABILITY OF ERTS-I IMAGERY TO THE STUDY OF SUSPENDED 
SEDIMENT AND AQUATIC FRONTS 
V, Klemas, R. Srna, W, Treasure, M. Otley, College of Marine Studie8, University 
of Dele wart? 
Xmagery from three uccessful ERTS-1 pae es over the Delaware Bay 
and Atlantic Coastal Region have been evaluated to  determine v i s i b i l i t y  
of aquatic features.  Data gathered from ground t ru th  teama before and 
during the overf l igh  ts , i n  conjunction with aerial pho tographs taken at  
various alt%tudee,were used t o  in t e rp re t  the imagery. !l!he overpasses 
took place on August 16, October 10, 1972, and January 26, 2973, with 
cloud cover ranging from about zero t o  twenty percent. 
1024-15073, 1079-15133, and 1187-15140). Visual inspection, density 
s l i c ing  and mult ispectral  analysis of the imagery revealed s trong sus- 
pended sediment pat terns  and eeveral  d i s t i n c t  types of aquatic 
interfaces  o r  f ron ta l  systems. 
(1.D. Nos. 
The in te r faces  are’ a major hydrographic feature  i n  Delaware Bay 
and frequently include regions of high convergence. 
i n  the upper and middle bay and interfaces  tend t o  a l ign  along the flow 
axis of the river or  p a r a l l e l  t o  the shoreline.  
during the ebb portion of the t i d a l  cycle and seem t o  be associated with 
veloci ty  shears induced by differences i n  bottom topography. Boundaries 
l i k e  the one shown i n  Figure 2 exhibi t  a strong change i n  color and 
turbidi ty ,  with Secci depths changing by roughly a f ac to r  of two as one 
crosees them. 
Figure 3, which ehows a boundary moving acroas the anchored fluoreaewh 
dye pack, and capturing and holding the end of the dye streak. 
placement of portions of the waEe of a ship crossing a boundary, shown 
i n  Figure 4, is an indicat ion of shear a loni  the boundary. 
break up the boundaries, with three dimensional patches of the more tur- 
b id  water not mixing with the less turbid water, but  clinging together 
up t o  one hour a f t e r  the boundary i t s e l f  has been destroyed. 
As shown i n  Figure 1, 
They are strongest 
Convergence of these boundaries i a  i l l u s t r a t e d  i n  
The dis- 
S t o m  tend to  
https://ntrs.nasa.gov/search.jsp?R=19730019611 2020-03-17T08:52:16+00:00Z
The second type of i n t e r f a c e ,  shown i n  Figure 5 ,  is primari ly  
a t i d a l  i n t r u s i o n  of t h e  s h e l f  water during i n c i p i e n t  f lood t i d e ,  with 
associated d i s c o n t i n u i t i e s  i n  s a l i n i t y  and temperature. The con- 
vergence proper t ies  of such f r o n t s  a t t ract  heavy accumulations of 
foam which were found t o  contain s t rong concentrations of t o x i c  
substances. 
bay water, tends t o  pene t ra te  i n t o  the  bay along the deep channel, and 
thus e s t a b l i s h  higher s a l i n i t y  i n  t h e  middle than near the  shores  of 
the  bay. 
is moving along t h e  deep channel of the  bay. 
The she l f  water, having higher  s a l i n i t y  and densi ty  than 
(Figure 6). Thus the  apex of the  f r o n t a l  wedge i n  Figure 5 
Figure 7 shows ERTS-1 imagery of t h e  mouth of Delaware Bay i n  
band 5 obtained on August 16, 1972. 
sediment plumes was obtained i n  band 5. 
l o c a l l y  suspended sediment is v i s i b l e  above t h e  shoals near Cape May. 
One boundary is v i s i b l e  near the middle of the  bay mouth, a second one 
protrudes i n  t h e  souther ly  d i r e c t i o n  from Cape Henlopen, and a t h i r d  one 
extends i n  t h e  southeas te r ly  d i r e c t i o n  f u r t h e r  south , near Indian River 
Inlet .  
in 18 f e e t  of depth noted a change i n  v i s i b i l i t y  from two f e e t  t o  s i x  
f e e t  as t h e  boundary passed over the  tower they were working on. 
9 shows t h e  boundary approaching the beach two miles north of Indian 
River In le t .  
seen from an a i r c r a f t .  
was near peak, f lood ve loc i ty  a t  the  mouth of the bay. 
ometry traces between the Capes i n  Figure 7, seem t o  correlate with t h e  
depth p r o f i l e ,  most of t h e  v i s i b l e  suspended sediment should represent  
sand from l o c a l  shoals  and shallow areas put  i n t o  temporary suspension 
by the  f lood cur ren t  and waves. 
measurements seem t o  support  t h i s  conclusion. 
more complex during ebb t i d e  when l a r g e  q u a n t i t i e s  of s i l t  and c lay  
are a l s o  present.  
Best v i s i b i l i t y  of boundaries and 
As i l l u s t r a t e d  i n  Figure 8, 
This boundary was moving rapidly a t  t h e  time and divers  operat ing 
Figure 
Figure 10 shows a similar boundary moving shoreward, as 
The t i d e  condition a t  t h e  time of t h e  ERTS-1 pass 
Since microdensit- 
Sample analyses and Secci depth 
This r e l a t i o n s h i p  becomes 
1276 
Figures 11 and 12 show band 5 imagery from ERTS-1 passes 
over Delaware Bay on October lo th ,  1972, and January 26th, 1973 
respectively.  
i n  the  bay at  t he  t i m e  of the respect ive ERTS-1 overpasses. 
on October 10th there  w a s  high water s lack at  the  baymouth and peak flood 
near the Chesapeake and Delaware Canal, i n  the  upper portion of t he  
bay. 
boundaries are v i s i b l e  i n  Figure 11 i n  the upper portion of t he  bay. 
In  cont ras t ,  according t o  Figure 14, on January 26th, the baymouth w a s  
flooding; near t he  C & D Canal t he  t i d e  was  ebbing; and there  w a s  a 
high s lack i n  the upper half  of the  bay. 
i n  Figure 1 2  shows considerable mixing and less boundary formation i n  
the  upper portion of the bay than the  image i n  Figure 11. 
Figures 13 and 14 describe the t i d a l  conditions 
Note tha t  
(Figure 13). Therefore, as i l l u s t r a t e d  in  Figure 15, very strong 
Therefore the  ERTS-1 image 
The three t ranssec ts  across the  bay shown i n  Figure 15 are 
traversed by boats and low a l t i t u d e  a i r c r a f t  during ERTS-1 overpasses 
t o  co l l ec t  ground t ru th .  
radio,  t o  d i rec t  t he  ground teams t o  s ta t ions .  A t  each s t a t ion ,  
water samples were takhn a t  the surface and/or one meter depth. 
depth, temperature, color and s a l i n i t y  w e r e  a l s o  recorded. The water 
samples were f i l t e r e d  using a Mill ipore f i l t r a t i o n  apparatus and 
54mn Gilman g la s s  f i l t e r  pads. 
dessicated and weighed t o  determine the  mass of the  par t icu la te  matter. 
Carbon analyses w e r e  run on f i l t e r  pads from each s t a t i o n  t o  determine 
t o t a l  percent carbon, by weight. 
presently being conducted on the  remaining f i l t e r  pads, t o  determine 
clay mineralogy. Densitometer t r aces  and densi ty  s l i c i n g  across a l l  
ERTS-1 bands are current ly  being correlated with suspended sediment 
load, sediment s i z e ,  Secci depth and other  parameters. (Figure 16). 
Boats and a i r c r a f t  were coordinated via 
Secchi 
The f i l t e r  pads were dried at 1OS0C, 
X-ray d i f f r ac t ion  analyses are 
1277 
Before t h e  October 27, 1972, pass of ERTS-1, an 800 foot  wide 
s l i c k  of Rhodamine-B dye w a s  i n s e r t e d  a t  t h e  proposed e i g h t  mile site 
f o r  an offshore o i l  terminal,  as shown i n  Figure 17. 
prevented t h e  satell i te from imaging t h e  dye s l i c k ,  however, a i r c r a f t  
t racking t h e  dye patch recorded a boundary sweep across t h e  dye patch 
s t r e t c h  it along t h e  boundary, and car ry  i t  about a mile towards 
t h e  bay during flood t ide .  
Figure 18, a t  t h e  end of i t s  one m i l e  t r a v e r s a l ,  using narrowband red 
f i l t e r s  t o  enhance t h e  weakened dye concentration. 
involving dye drops, sludge and ac id  disposal  during ER3S-1 overpasses 
w i l l  be  c a r r i e d  out  during t h e  coming s i x  weeks. 
Cloud cover 
The s t re tched  dye s l i c k  i s  shown i n  
Coordinated experiments 
ERTS-1 Mult ispectral  scanner band 5 (0.6-0.7 microns) gave t h e  
sharpest  d e f i n i t i o n  of i n t e r f a c e s  between w a t e r s  o f  d i f f e r i n g  t u r b i d i t y .  
Band 4 (0.5-0.6 microns), due t o  i t s  deeper water penetrat ion,  w a s  more 
s e n s i t i v e  t o  p a t t e r n s  having lower t u r b i d i t y ,  ye t  w a s  ve i led  by a 
uniform blanket of atmospheric s c a t t e r i n g  making i d e n t i f i c a t i o n  of 
sediment p a t t e r n s  more d i f f i c u l t .  Band 6 (0.7-0.8 microns) and band 7 
(0.8-1.1 microns) c l e a r l y  del ineated the shore l i n e  and discriminated 
water from land i n  t h e  marshes. 
This pro jec t  is  p a r t l y  funded through ONR Geography Programs, 
Contract No. N00014-69-A0407; and NASA-ERTS-1, Contract No. 
NAS5-21837. 
1278 
Figure 1: Aquatic interfaces and frontal systems observed i n  Delaware Bay. 
f .  
Figure 2: A shear boundary near the Delaware Coast. 
1279 
Figure 3: Dye experiment to show convergence properties of boundary. 
Figure 4 :  Shear visible in displacement of wake of ship crossing boundary. 
1280 
Figure 5: Frontal system due to salt water intrusion into Delaware Bay. 
Figure 6: Salinity distribution in Delaware Bay.  
1281 
Figure 7: Aquatic boundaries and suspended sediment plumes identified 
in the ERTS-1 image of August 16, 1972, shown in Figure 6. 
1282 
Figure 8: ERTS-1 image of the mouth of Delaware Bay 
(Band 5, August 16, 1972, I , D ,  1024-15073), 
1283 
Figure 9 :  Boundary i n  ERTS-1 picture of  Figure 7 seen approaching the beach. 
Figure 10: Aircraft picture of boundary near Indian River Inlet. 
1284 
: ERTS-1 image of Delaware Bay obtained i n  band 5 on 
October 10, 1972. (I.D. No, 1079-15133). 
1285 
Figure 12: ERTS-1 image of  Delaware Bay obtained in  band 5 on 
January 26, 1973, ( L D e  No, 1187-15140) 
1286 
‘THREE HOURS AFTER MAXIMUM FLOOD AT DELAWARE BAY ENTRANCE 
Figure 13 Tidal e d i t i o n 8  in  Delaware Bay at the tbva of the 
ERTS-1 8- in  FigUte 11. Thr Upper bw $8 
mar maximum flood, rerulting i n  aham &eat2 boundarier. 
1287 
Figure 14 
ONE HOUR bEFORE MAXlMljM FLOOD AT DFIAWARC RAY ENTRANCE 
Tidal conditions i n  Delaware Bay at the t i m e  of the ERTS-1 
image shown in Figure 12. 
slack, causing boundaries to weaken and more mixing to occur. 
The upper bay is  near high water 
1288 
Figure 15: Aquatic boundaries and suspended sediment v i s ib l e  in ERTS-1 
image of pctober 10, 1972, shown i n  Figure 11. 
of boats and a i r c r a f t  col lect ing ground t ru th  are shown 
i n  the upper, middle and lower Delaware Bay. 
Transsects 
Figure 16: Result of Color Density S1.Ecing of ERTS-1 Image of Figure 11. 
(October 10, 1972, pass over Delaware baymouth). 
1289 
Figure 17: Rhodamine-B dye patch injected at proposed &mile off-shore 
o i l  terminal site. The size of the patch i s  about 800 feet. 
F'igure 18: Dye patch i s  captured by moving frontal systems and carried 
one m i l e  towards the Bay. 
1290 


Applicability of ERTS-1 imagery to the study of suspended sediment and aquatic fronts

There are no author-identified significant results in this report

"Made available under NASA:spAorif6mh
in the interest of early arid wide dis-
semination of Earth Resources Survey
Program information and without liability
for any use made thereof."
APPLICABILITY OF ERTS-- IMAGERY TO THE STUDY
OF SUSPENDED SEDIMENT AND AQUATIC FRONTS
V. Klemas, R. Srna, W. Treasure, M. Otley
College of Marine Studies
University of. Delaware
UN 362 SR 9654
March 20, 1973
Summary of Significant Results
E7.3 1 0.3 6.8
VE lbloo0
D*o of Illustrations Irthis. document may be better
studied on microfiche
Prepared for
GODDARD SPACE FLIGHT CENTER
GREENBELT, MD. 20771
(E73-10368) APPLICABILITY OF ERTS-1 N73-19364
IIMAGERY TO THE STUDY OF SUSPENDED
SEDIMENT AND AQUATIC FRONTS (Delaware
Upniv.) 17 p HC $3.00 CSCL 08H Unclas
G3/13 00368
Original photography rMy be purchasd from.
EROS DA CcIA sM
O1th3 aid :akda Avenue
Sioux Falis, SD .57S1
_ w j d
17
https://ntrs.nasa.gov/search.jsp?R=19730010637 2020-03-23T03:32:57+00:00Z
APPLICABILITY OF ERTS-1 IMAGERY TO THE STUDY
OF SUSPENDED SEDIMENT AND AQUATIC FRONTS
V. Klemas, R. Srna, W. Treasure, M. Otley
College of Marine Studies
University of Delaware
Imagery from three successful ERTS-1 passes over the Delaware Bay
and Atlantic Coastal Region have been evaluated to determine visibility
of aquatic features. Data gathered from ground truth teams before and
during the overflights, in conjunction with aerial photographs taken at
various altitudes,were used to interpret the imagery. The overpasses
took place on August 16, October 10, 1972, and January 26, 1973, with
cloud cover ranging from about zero to twenty percent. (I.D. Nos.
1024-15073, 1079-15133, and 1187-15140). Visual inspection, density
slicing and multispectral analysis of the imagery revealed strong sus-
pended sediment patterns and several distinct types of aquatic
interfaces or frontal systems.
The interfaces are a major hydrographic feature in Delaware Bay
and frequently include regions of high convergence. As shown in Figure 1,
in the upper and middle bay and interfaces tend to align along the flow
axis of the river or parallel to the shoreline. They are strongest
during the ebb portion of the tidal cycle and seem to be associated with
velocity shears induced by differences in bottom topography. Boundaries
like the one shown in Figure 2 exhibit a strong change in color and
turbidity, with Secci depths changing by roughly a factor of two as one
crosses them. Convergence of these boundaries is illustrated in
Figure 3, which shows a boundary moving across the anchored fluorescein
dye pack, and capturing and holding the end of the dye streak. The dis-
placement of portions of the wake of a ship crossing a boundary, shown
in Figure 4, is an indication of shear along the boundary. Storms tend to
break up the boundaries, with three dimensional patches of the more tur-
bid water not mixing with the less turbid water, but clinging together
up to one hour after the boundary itself has been destroyed.
I
The second type of interface, shown in Figure 5, is primarily
a tidal intrusion of the shelf water during incipient flood tide, with
associated discontinuities in salinity and temperature. The con-
vergence properties of such fronts attract heavy accumulations of
foam which were found to contain strong concentrations of toxic
substances. The shelf water, having higher salinity and density than
bay water, tends to penetrate into the bay along the deep channel, and
thus establish higher salinity in the middle than near the shores of
the bay. (Figure 6). Thus the apex of the frontal wedge in Figure 5
is moving along the deep channel of the bay.
Figure 7 shows ERTS-1 imagery of the mouth of Delaware Bay in
band 5 obtained on August 16, 1972. Best visibility of boundaries and
sediment plumes was obtained in band 5. As illustrated in Figure 8,
locally suspended sediment is visible above the shoals near Cape May.
One boundary is visible near the middle of the bay mouth, a second one
protrudes in the southerly direction from Cape Henlopen, and a third one
extends in the southeasterly direction further south, near Indian River
Inlet. This boundary was moving rapidly at the time and divers operating
in 18 feet of depth noted a change in visibility from two feet to six
feet as the boundary passed over the tower they were working on. Figure
9 shows the boundary approaching the beach two miles north of Indian
River Inlet. Figure 10 shows a similar boundary moving shoreward, as
seen from an aircraft. The tide condition at the time of the ERTS-1 pass
was near peak flood velocity at the mouth of the bay. Since microdensit-
ometry traces between the Capes in Figure 7, seem to correlate with the
depth profile,l most of the visible suspended sediment should represent
sand from local shoals and shallow areas put into temporary suspension
by the flood current and waves. Sample analyses and Secci depth
measurements seem to support this conclusion. This relationship becomes
more complex during ebb tide when large quantities of silt and clay
are also present.
Figures 11 and 12 show band 5 imagery from ERTS-1 passes
over Delaware Bay on October 10th, 1972, and January 26th, 1973
respectively. Figures 13 and 14 describe the tidal conditions
in the bay at the time of the respective ERTS-1 overpasses. Note that
on October 10th there was high water slack at the baymouth and peak flood
near the Chesapeake and Delaware Canal, in the upper portion of the
bay. (Figure 13). Therefore, as illustrated in Figure 15, very strong
boundaries are visible in Figure 11 in the upper portion of the bay.
In contrast, according to Figure 14, on January 26th, the baymouth was
flooding; near the C & D Canal the tide was ebbing; and there was a
high slack in the upper half of the bay. Therefore the ERTS-1 image
in Figure 12 shows considerable mixing and less boundary formation in
the upper portion of the bay than the image in Figure 11.
The three transsects across the bay shown in Figure 15 are
traversed by boats and low altitude aircraft during ERTS-1 overpasses
to collect ground truth. Boats.and aircraft were coordinated via
radio, to direct the ground teams to stations. At each station,
water samples were taken at the surface and/or one meter depth. Secchi
depth, temperature, color and salinity were also recorded. The water
samples were filtered using a Millipore filtration apparatus and
54mm Gilman glass filter pads. The filter pads were dried at 1050 C,
dessicated and weighed to determine the mass of the particulate matter.
Carbon analyses were run on filter pads from each station-to determine
total percent carbon, by weight. X-ray diffraction analyses are
presently being conducted on the remaining filter pads, to determine
clay mineralogy. Densitometer traces and density slicing across all
ERTS-1 bands are currently being correlated with suspended sediment
load, sediment size, Secci depth and other parameters. (Figure 16).
Before the October 27, 1972, pass of ERTS-1, an 800 foot wide
slick of Rhodamine-B dye was inserted at the proposed eight mile site for an
offshore oil terminal, as shown in Figure 17. Cloud cover prevented
the satellite from imaging the dye slick, however, aircraft tracking
the dye patch recorded a boundary sweep across the dye patch, stretch
it along the boundary, and carry it about a mile towards the bay
during flood tide. The stretched dye slick is shown in Figure 18,
at the end of its one mile traversal, using narrowband red filters to
enhance the weakened dye concentration. Coordinated experiments
involving dye drops, sludge and acid disposal during ERTS-1 overpasses
will be carried out during the coming six weeks.
ERTS-1 Multispectral scanner band 5 (0.6-0.7 microns) gave the
sharpest definition of interfaces between waters of differing turbidity.
Band 4 (0.5-0.6 microns), due to its deeper water penetration, was more
sensitive to patterns having lower turbidity, yet was veiled by a
uniform blanket of atmospheric scattering making identification of
sediment patterns more difficult. Band 6 (0.7-0.8 microns) and
band 7 (0.8-l.l1microns) clearly delineated the shoreline and dis-
criminated water from land in the marshes.
This project is partly funded through NSF-RANN, Grant GI-33369;
NOAA Office of Sea Grant, Grant No. GH-109; and NASA-ERTS-1, Contract
No. NAS5-21837.
I '



Aquatic boundaries and suspended sediment plumes identified
in the ERTS-1 image of August 16, 1972, shown in Figure 6.
Figure 7:




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THREE H-OURS AFTER MAXIMUM FLOOD AT DELAWARE BAY £NTRANCE
Tidal conditions in Delaware Bay
ERTS-1 image shown in Figure 11.
near maximum flood, resulting in
at the time of the
The upper bay is
sharp shear boundaries.
13
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Figure 14 Tidal conditions in Delaware Bay at the time of the ERTS-1
image shown in 'Figure 12. The upper bay is near high water
slack, causing boundaries to weaken and more mixing to occur.
14
39°x _




Applicability of ERTS-1 imagery to the study of suspended sediment and aquatic fronts

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