The author has identified the following significant results. Comparison of late season U-2 color infrared sea ice photography and early ice season LANDSAT sea ice imagery has made possible the identification of subtle features seen on early season LANDSAT imagery in the near shore areas. The U-2 imagery positively linked these features to ice conditions generally not observable by LANDSAT because of the time of year when they take place. Ice formed in place largely as single sheets appears light while ice deformed by considerable rafting appears darker when viewed on LANDSAT imagery. Because the ice is snow-covered at the time this imagery is obtained, this underlying structure must be revealed by the topography of the snow surface, and the resulting light scattering characteristics

Stringer, W. J.

English

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Produced by the NASA Center for Aerospace Information (CASI) 
https://ntrs.nasa.gov/search.jsp?R=19760006469 2020-03-22T17:22:37+00:00Z
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€- SECOND QUARTERLY PROGRESS REPORT{_
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F. TITLE OF INVESTIGATION:	 LANDSAT Survey of Near-Shore Ice Conditions
Along the Arctic Coast of Alaska
B. PRINCIPAL INVESTIGATOR: 	 Dr. William J. Stringer
"'u,	 C. PROBLEMS IMPEDING INVESTIGATION:	 None,,.
r1	 N
•^	 D. PROGRESS REPORT:
I	 U a
z	
° 1.	 Accomplishments This Reporting Period:	 .
s a.	 Presentation of Scientific Paper. 	 A paper "Ice Motions in
the Vicinity of a Grounded Floeberg" was presented at the
° Port and Ocean Engineering Under Arctic Conditions (POAC)
Conference held in Fairbanks during August 1975.	 This work
CD
was partly described under 'Significant Results' 	 in our
w w
	
,, first quarterly report.
uo	 u
n N 
W 
u b.	 Compilation of Prior-to-Contract LANDSAT Data of Ice Conditions
Along Alaskan Coact.
	
1:2,500,000 maps of Alaska were pre-
pared sho^,ing the center points of all Alaskan coastal 	 LANDSAT
z N data .';ith less than 20% cloud cover. 	 One map was made for°
each major sea-ice related coast (Beaufort, Bering, Chukchi)
°	 b for each LANDSAT cycle.
w .s N
c.	 Acquisition of Hard Copy LANDSAT Sea Ice Data. 	 The mapst34
= = w developed in	 'b'	 were used as a quide to determine which
^ r LANDSAT cycles gave the best coverage of the areas under
z ; consideration.	 Then hard copy of 1:500,000 scale of all
N U r+ data for selected cycles were ordered from the Sioux Falls
x laboratory.	 Generally, for each ice year one very early
a NM (February-March) and one late (June-July) cycle was selected.
V. w The cost of this order was divided among a number of pro-
c^ r.w
jects, this project funding approximately one-third the
H entire order.
C? Z	 toO C d.	 Preparations to Hap at 1:500,000 Scale Completer (see Section
D.2.a).	 A major problem encountered when attempting to map
w u ^ U near shore ice conditions along a snow-covered coast is that
the shore line often is not recognizable over an entire LANDSAT
image, but yet pressure ridges, leads and other ice features
are very easily recugnized.	 To solve this problem, clear
plastic overlays have been prepared from a 1:500,000 map base
which show the coast, and sufficient major topographical fea-
tures such that the image and map may be brought into regis-
tration.	 Ice maps are then prepared by tracing pertinent
informatic , .	 from this superimposed pair.
iS	 ^^.b
x/306
Using a pantograph, bathmetric data was transferred from
standard U.S. Coast and Geodetic Survey maps to these over-
lays. This was a time-consuming but very important accom-
plishment. Many near-shore ice features are related to
bathmetry and this relationship must be taken into con-
sideration. Yet the existing detailed charts have been pre-
pared at a wide range of scales from 1:700,000 to 1:400,000.
This made necessary the rather tedious work with the panto-
graph.
e. Aircraft Data Was Obtained. See Section J.1., "Aircraft
Data".
f. Preparation of Sea-Ice Maps Begun. Using 1:500,000 hard copy
LANDSAT data and overlays.described above, maps of near shore
ice conditions for the Beaufort Sea during 1974 have been made
for the earliest complete LANDSAT cycle. These maps represent
only the first step towards analysis of ice conditions for that
year. Some preliminary analysis has been greatly enhanced by
the availability of NASA-provided U-2 photography along the
Beaufort Sea coast for that year. (See plans for next reporting
period.) (See also Section J.2. on the utility of U-2 photo-
graphy.)
2. Accomplishments by Others this Reporting Period Directly Related
to this Project
a. 1:500,000 scale color-additive viewer. The University of
Alaska iA DSAT coordination program has obtained a 1:500,000
sple I S color-additive viewer to replace the existing
I S 1:1,000,000 scale color-additive viewer previously
available. This is a significant accomplishment, greatly
enhancing our data analysis capabilities.
E. INTERACTION WITH OTHER INVESTIGATORS AND AGENCIES
1. Communications with the Habitat Protection Division, Alaska
Department of Fish and Game have established that a signifi-
cant benefit to their coastal zone management tasks could be
ORIGINAL PAGE is obtained from certain aspects of this study as currently planned
OF PppR QUALITY and also from a small amount of additional work not antici-pated. We plan to work as closely with this potential user of
our data as possible, still keeping in mind that as interest
in petroleum exploitation along the Alaskan coast increases,
there will be many other interested groups and agencies and
we should still follow our initial objectives of studying and
locating hazardous ice conditions along these coastal areas.
F. PLANS NEXT REPORTING PERIOD
During this period we will concentrate on producing maps of ice
conditions along the Alaskan coast. Hard copy LANDSAT data de-
scribed above will be used for beginning and end of ice season
maps. The color-additive viewer will be used to produce maps
intermediate of those times. Some interpretation will be made
`)--
but it would be unwise to concentrate on this aspect of the pro-
ject until ice conditions from year to year can be studied and
compared. This mapping process should be nearly completed by
the end of the next reporting period.
G. RECOMMENDATIONS
We again recommend that low sun -angle LANDSAT data of the Alaskan
coastal areas be obtained. Not only would this extend the time
of coverage of data into the ice season, but also the low sun-
angle enhances identification of many ice features -- particularly
pressure ridges.
N. FUNDS EXPENDED
As of August 30, 1975, the total funds expended by this project
were $7,176, from a total budget of $28,337.
I. DATA USE
Value of Data Received
Value of data allowed
	
Value of data ordered
	
as of 9/30/75
$5,900
	
Standing Order
	
$2,201.75
J. AIRCRAFT DATA
1. Recent Data Acquisition. As part of the Outer Continental Shelf
environmental assessment program, a U. S. Geological Survey air-
craft flew a reconnaissance flight from Barrow to Cross Island
during June 1975. Side-looking airborne radar and wide-angle
panchromatic photography were obtained. This data has been
archived at the remote sensing library at the University of
Alaska and will be a valuable asset to this project.
2. Utility of NASA-Provided Photography. Mention was made in
Section D.l.f. of NASA-provided U-2 photography. We have
found this color-infrared photography to be of great value
in interpreting LANDSAT imagery. We plan to analyze the
LANDSAT data coincident with this photography in great de-
tail before analyzing other LANDSAT scenes. Based on our
examinations to date, our confidence in LANDSAT ' s ability
to distinguish ice conditions has been elhanced well beyond
earlier expectations. It should be notes that this photo-
graphy was obtained in early July, toward the end of the
normal ice season. At this late date, the snow had long
since melted from the ice, baring the structure of various
ice features for close examination.
K. PUBLICATIONS
1. Attached is a copy of The Northern Engineer containing our
article on Katie's Floeberg.
3
II ^ -
	
--	
.
f	 '
^	 _	 1
E
S
2. The written version of the paper "Ice Motions in the Vicinity
of a Grounded Floeberg" is in preparation and should be avail-
able shortly.
L. SIGNIFICANT RESULTS
See attached sheet.
SECOND QUARTERLY PROGRESS REPORT
LANDSAT FOLLOW-ON INVESTIGATION
No. - +-.Fj —
(^z Is 00
TITLE: LANDSAT Survey of Near-Shore Ire Conditions along the Arctic
Coast of Alaska
PRINCIPAL INVESTIGATOR: William J. Stringer
DISCIPLINE: Oceanography
SUBDISCIPLINE: Ice Dynamics
SUINZIARY OF SIGNIFICANT RESULTS: Comparison of late season U-2 color
infrared sea ice photography and early ice season LANDSAT sea
ice imagery has made possible the identification of subtle fea-
tures seen on early season LANDSAT imagery in the near shore areas.
The U-2 imagery positively linked these features to ice conditions
generally not observable by LANDSAT because of the time of year
when they take place. In particular, ice formed in place largely
as single sheets appears light while ice deformed by considerable
rafting appears darker when viewed on LANDSAT imagery. Because
the ice is snow-covered at the time this imagery is obtained, this
underlying structure must be revealed by the topography of the
snow surface; and the resulting light-scattering characteristics.
5


Landsat survey of near-shore ice conditions along the Arctic coast of Alaska

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