Arctic Marine Domain Awareness
Global Perspectives
2/18/2016
Slide 1 - Introduction
Hello. My name is Orson Smith. I am a Professor Emeritus of Civil Engineering with the University of Alaska
Anchorage, College of Engineering.
This is the first of 3 presentations that will provide an overview of public information available about conditions in
the Arctic marine environment. The focus will be on the US Arctic and adjacent waters, but some sources provide
global data. The series is intended to prepare managers, engineers, planners, and others with useful resources for
operations and developments offshore and along the coast of Alaska.
We’ll review some basics of Earth science for understanding and interpreting available information. Then we’ll take
a look at current products of public web sites, for which links are provided on the slides. Challenge questions are
provided for participants to test their comprehension. This narration script is available for download and links to
tutorials and to additional background material are also provided along the way.
The short course is sponsored by the Department of Homeland Security through its Arctic Domain Awareness
Center, established in 2014 at UAA.
I gratefully acknowledge helpful review comments to this first presentation provided by my colleague John Bean,
Associate Professor, UAA Department of Geomatics.
Let’s get started.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 2 – Topics
Topics discussed in this introductory presentation lay a foundation for sitespecific information on Arctic weather and sea conditions presented in
following presentations. Basics of Earth geometry, positioning, mapping, and
time zone definitions are discussed, with reference to relevant public
information available online. These fundamentals will lead us to review
currently prevailing definitions of the Arctic region and large-scale
bathymetry and circulation features of the Arctic Ocean and adjacent seas
off Alaska.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 3 – Earth Coordinates
We’ll begin with a quick review of Earth coordinates, to set the stage for positioning
and astronomical information available online.
The most common and universally applied system for location on the surface of the
Earth consists of north-south latitude and east-west longitude coordinates on an
assumed spherical planet.
Latitude is an angle from the center of the Earth between the plane of the equator
and the axis of rotation. Latitude goes from 0 degrees at the equator to 90 degrees
N at the North Pole or to 90 degrees S at the South Pole. Lines of latitude along the
surface of the Earth are parallel to the equator and are often called “parallels.” A
nautical mile is the north-south distance along a longitudinal meridian that includes
1/60 degree or one “minute” of latitude. A nautical mile is about 10% longer than a
statute mile.
Longitude is an angle in the plane of the equator from 0 degrees at the Prime
Meridian, which passes through Greenwich, near London in the UK. Longitude
increases westward from the Prime Meridian to 180 degrees W and eastward to 180
degrees E at the International Date Line, on the opposite side of the Earth from
Greenwich. Lines of longitude, called “meridians,” are not parallel. Each 15
change of longitude corresponds to 1 hour’s rotation of the Earth in a 24-hour day.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 4 – Standard World Time Zones
The Earth revolves every 24 hours, so every 15 degrees of revolution is
equivalent to 1 hour. The time zones actually applied in various countries
follow political boundaries. Nowhere is the departure from the natural 15degree hour more pronounced than in Alaska, where a single time zone
stretches across 5 natural 15-degree time zones. Alaska time is notably 9
hours earlier than “Coordinated Universal Time,” abbreviated “UTC,” also “Z”
or “Zulu” in the phonetic alphabet. UTC is equivalent to the more traditional
“Greenwich Mean Time” or “GMT,” which notes that the “Prime Meridian,”
or line of 0 degrees longitude, passes through Greenwich, UK (near London).
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 5 – CORS Stations in Alaska
The US Global Positioning System (GPS) consists of 24 satellites orbiting the Earth,
which communicate with phones and other devices equipped for GPS positioning.
The accuracy provided by ordinary GPS receivers is sufficient for most practical
matters.
GPS position accuracy can be improved to surveying standards by application of
measurements from stationary reference stations that are in communication with
the same satellites as a mobile GPS device. This arrangement, known as Differential
GPS (DGPS) calls for stationary reference stations within about 250 km of a mobile
GPS device. Various agencies have collaborated in the US to establish a network of
Continuously Operating Reference Stations (CORS) that provide the information
necessary for 3-dimensional position accuracy on the order of a centimeter.
The situation in the Alaska Arctic often calls for project-specific arrangements to
improve ordinary GPS accuracy, since CORS stations are so sparse in this region.
Surveyors can establish temporary stationary reference stations with radio telemetry
for real-time kinematic (RTK) mobile positioning with 3-d position accuracy on the
order of a few centimeters. Specialized equipment and knowledge must be
applied to achieve RTK-DGPS accuracy. Ideally the fixed station would be no more
than 10 to 20 km from the operations site. This requirement can be an expensive
challenge for offshore operations that need precise positioning.
More information on the US GPS system and on international Global Navigation
Satellite System (GNSS) services is available at the GPS web site
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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(http://www.gps.gov/) and NOAA’s National Geodetic Survey website
(http://www.ngs.noaa.gov/).
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 6 - Automatic Identification Systems
Use of Automatic Identification Systems (AIS) is becoming an accepted
standard worldwide for near-continuous reporting and monitoring of ships’
positions at sea. An international network involves marine-band VHF radio
transponders aboard subscribing ships and shore stations operated by
organizations such as the Marine Exchange of Alaska. Subscribing ships can
receive information about the locations and tracks of other AIS-equipped
ships nearby. Subscribing shoreside entities, such as port administrations, can
monitor all AIS-reported traffic in their vicinity. AIS systems are being
continually enhanced to provide a growing variety of marine domain
awareness information.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 7 – Map projections
Paper land maps and ocean nautical charts have been used for navigation for centuries. Portrayal of the geography of a spherical Earth on a flat sheet of paper requires projection. The same goes for a modern flat screen of an Electronic Chart Display and Information System (ECDIS). Electronic navigation systems provide visual information using projections identical to those of a printed paper chart. The projection of a chart is noted in the information inserts on printed NOAA nautical charts and USGS topographic maps and is also provided for ECDIS charts.
A cylindrical projection is illustrated in the left‐hand figure on the slide. Near the equator, in the illustrated case, the shapes of coastlines are accurately portrayed by a cylindrical projection, but distortions increase at high latitudes. The Mercator projection to the right is most common for nautical charts. Mercator projection charts apply a modified cylindrical projection to create a flat image which shows lines of constant course, or rhumb lines, as straight lines on the chart. Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 8 – Polar projections
Other non-cylindrical projections minimize distortions of polar
coastlines, but lose the intuitive navigation advantages of the
Mercator projection. Modern ECDIS systems and GIS mapping
software can readily compensate for these issues in computations.
Visual perspectives of geographical relationships are affected by
projection and users of maps and charts for Polar Regions should be
aware of this fact.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 9 – Datums
Mapping coordinate systems use horizontal and vertical datums to
define their numerical scales. A change from one horizontal datum to
another can mean an error of 100 m or more in position accuracy.
NAD83 or the nearly equivalent WGS84 horizontal datums are most
commonly applied for nautical charts and marine navigation devices.
Vertical datums can be challenging in their diversity. Inland and
shoreline elevations generally refer to a tide statistic, either a nominal
mean sea level or water level statistics from recordings at NOAA
master tide stations for a tidal epoch of 19 years. Astronomical tides
can generally be accurately predicted, but tide levels vary
geographically due to changes of shoreline shape and due to
astronomical tide generating factors. Secondary tide recording
stations with less than 19 years’ record provide corrections to nearby
tidal epoch predictions.
As with CORS stations, tide recordings are sparse along the Arctic
Alaska coast and therefore tide predictions are less reliable well away
from a tide recording station. Tide prediction information and effects
of wind-induced water level changes, like storm surges, will be
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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discussed more, later in this course.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 10 – Ellipsoid Datums
Smooth “squashed-sphere” ellipsoid shapes have been
mathematically defined to establish vertical datums that are
independent of tidal variations. An ellipsoid vertical datum lacks
regional variations in gravity associated with mountains, valleys, and
heavy mineral deposits, but is expediently applied with modern
surveying field equipment. Transformation between geoid and
ellipsoid datums is readily accomplished with public domain and with
commercial GIS software.
The link on the slide (http://vdatum.noaa.gov/docs/datums.html)
leads to a NOAA tutorial on datums, which is the source of the figure.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 11 - Geoid
Modern use of GPS satellite measurements for navigation has led to
increasingly accurate maps of the Earth’s gravity field to which
orbiting satellites respond. A gravity map called a “geoid” establishes
a vertical datum for which the zero on the vertical scale approximates
global mean sea level. A geoid datum is independent of tide
variations from place to place.
Information about datums and software for datum transformations is
available from NOAA’s office of Geodetic Survey
(http://www.ngs.noaa.gov/).
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 12 – NOAA chart and USGS topographic map vertical datums
Coastal operations must recognize and deal with the conventional change of vertical datums from nautical
charts to topographic maps. Zero depth on a nautical chart is typically mean lower low water, a low tide level.
Zero elevation on a topographic map is typically mean high water, a high tide level. The intertidal zone lies
between these two vertical datums and can be a large area in the higher tide ranges of southwest, southcentral,
and southeast Alaska coastal zones. Boundaries of private land ownership and of State and federal jurisdiction fall
across the tidelands in the US. Issues of coastal land ownership are complicated by Alaska’s earthquakes and
related land subsidence and upheaval.
Information about tidal datums and access to nautical charts is available from NOAA’s Office of Coast Survey
(http://www.nauticalcharts.noaa.gov). Key tidal parameters include:
• Mean Sea Level (MSL): Average of hourly heights observed over a 19-year tidal epoch
• Mean High Water (MHW): Average of all high water elevations of each tidal day for a 19-year tidal epoch
• Mean Low Water (MLW): Average of all low water elevations of each tidal day for a 19-year tidal epoch
• Mean Lower Low Water (MLLW): Average of lower low water elevations of each tidal day for a 19-year tidal
epoch
These parameters rely on accurate long-term measurements at a specific coastal site. Without a full 19-year tidal
epoch’s measurements, less accurate measurements must suffice to define coastal boundaries noted in the slide.
Information about topographical mapping conventions and access to topographic maps is available from the US
Geological Survey (http://www.usgs.gov/pubprod/).
Information about tidal datums and hazards along the Alaska Coast is also available from the Alaska Department
of Natural Resources’ Division of Geological and Geophysical Surveys (http://dggs.alaska.gov/).
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 13 – Astronomical Tides
Ocean tides are driven primarily by gravity of the moon and secondarily by
gravity of the Sun. The Moon circles the Earth every 29 days with the familiar
repeating cycle of new Moon, quadrature (half-moon), full moon, and
another quadrature. Gravity of the Moon and of the Sun pull out bulges of
water that effectively travel around the Earth as the solid Earth rotates once
every 24 hours. This behavior of a moving wave with a crest passing at high
tide and a trough passing at low tide explains the rhythmic rise and fall of
the tides. The influence of the Sun and of the Moon are aligned at new and
full moon, so the bulges are exaggerated at these times and tidal ranges
are greater, called “spring tides.” The influence of the Sun and Moon are
out of line at each quadrature, so tidal ranges are muted, known as “neap
tides.”
Astronomical tides are not affected by weather on the Earth’s surface, so
weather-induced sea surface conditions are superimposed on tides.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 14 – Diurnal Inequality
The Earth and the Moon orbit every 29 days about a mutual center of
gravity. Centrifugal force causes a bulge of water on the Earth opposite the
Moon. The tractive force of the nearer Moon causes a bulge on the Moonside of the planet. This explains the fact that most places on Earth
experience 2 distinct high tides separated by 2 low tides each day. A lunar
day, the time for these two cycles to repeat, is 24 hours 50 minutes, since the
Moon is travelling in its orbit in the same direction as Earth’s daily rotation.
The time between successive high tides is thus 12 hours 25 minutes.
The plane of the Moon’s orbit around the Earth is not perpendicular the
Earth’s axis of rotation, so the bulges caused by the Moon’s gravity are not
symmetrical across the equator. Since the Earth rotates every 24 hours
beneath the tractive force causing bulges on the liquid ocean, most places
on Earth experience two tidal cycles each day, one with a higher ranges
than its predecessor and successor tidal cycles. This variation is known as
“diurnal inequality.”
Southwestern, southcentral, and southeastern Alaska have relatively high
tide ranges and dramatic diurnal inequality. The coasts of the Arctic Ocean
and adjacent seas off Alaska have relatively low tidal ranges and less
distinct diurnal inequality.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 15 – Arctic Coastal Tide Predictions
The presence of the continents affects the ideal equilibrium tide illustrated
on the previous two slides. Tidal predictions based on astronomical
parameters are still possible with sufficient measured data at specific coastal
sites. NOAA is the US agency with primary responsibility for tidal
measurements and predictions. The slide shows the scarcity of such
measurements along the northern Alaska coast. This issue prevails around
most of the Arctic. Tidal ranges are low, so this may not seem a critical
concern, but unfortunately there are other important reasons to measure
coastal water levels.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 16 - Wind-induced Water Levels Vs. Tides
High winds drive ocean water by friction. Storms drive extreme water level
changes along the coast know as “storm surges.” Wind-induced water level
changes are typically greater in the Arctic than the low-range astronomical
tides.
The slide shows a storm surge episode at Prudhoe Bay on the Alaskan
Beaufort Sea coast. The predicted astronomical tide is shown separately
from actual water levels recorded. The effect of wind-induced changes
superimposed on independent astronomical tides is clear. Also shown is the
fact that wind direction changes can bring either increased or decreased
water levels at the coast.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 17 – Tsunamis on the Alaska Coast
Tsunamis cause disastrous water level rises in the form of a fast-moving
destructive wave. These earthquake-induced water level changes are a
grave concern along the southeastern, southcentral, and Aleutian Island
coasts of Alaska.
Changes in geology and in water depths mitigate tsunami risks north of the
Aleutian Islands. Tsunami risk north of the Bering Strait is minimal.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 18 – Earth-Sun System
Information about weather and changing climate in the Arctic
requires a look at Earth-Sun system geometry.
The Earth’s axis of rotation is tilted 23 ½ degrees to the plane of its orbit
around the Sun. Sunlight effectively arrives along a straight-line path,
so the tilt of the Earth’s surface to the incoming Solar radiation matters
quite a bit.
This tilt is of greater consequence to seasonal heating than is Earth’s
slightly elliptical orbit around the Sun.
The 23 ½-degree tilt defines the climate regions of the Earth. The
northern hemisphere Tropic of Cancer and southern hemisphere Tropic
of Capricorn at 23 ½ degrees north and south latitude define the limits
of direct sunlight exactly normal to the Earth’s surface at the summer
solstice of each hemisphere.
The Arctic Circle and the Antarctic Circle at 66 ½ degrees north and
south latitudes define the places where no sunlight reaches the
surface at winter solstice and where the Sun never sets at summer
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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solstice.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 19 – US Naval Observatory
Predictions of sunlight and of moonlight and precise clock time are
important for planning offshore technical operations. The US Naval
Oceanographic Portal (http://www.usno.navy.mil/USNO) includes
services of the US Naval Observatory, such as:
- Precise clock time,
- Times of sunrise, sunset, and twilight at any location and date,
- Times of moonrise, moonset, and moon phases,
- Astronomical information for stellar navigation, and
- Downloadable astronomical data analysis software for prediction of
these parameters.
Other services of the US Naval Oceanographic Portal will be discussed
later in this course.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 20 – Oblique Solar Radiation
High latitudes receive much less solar energy than equatorial latitudes,
because of oblique incoming solar radiation.
Days and nights are of equal duration all over the Earth on Vernal
(spring) and Autumnal (fall) equinoxes. The Earth experiences the most
intense direct sunlight at the equator on an equinox, with symmetrical
reduction to the north and to the south.
Solar heating at an equinox at 60 degrees N, the latitude of my home
in Seward, Alaska, is half of that received per square meter at the
equator, as illustrated in the left-hand figure.
The right-hand shows relative incoming solar radiation per unit area at
the northern hemisphere summer solstice, the longest day of the year,
when Seward at 60 degrees N receives 65% of the solar heating
received at the Tropic of Cancer (23 ½ degrees N).
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Global Perspectives
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Slide 21 – Global Heat Balance
Abiding ecologies across the planet testify to an historical balance of
heat gain and loss. Given the substantial variation of solar heating
north and south of the equator, a global balance and generally stable
global temperature must be achieved by transport of heat energy
north and south in the atmosphere and in the ocean. North-south
circulation of heat is essential to long-term stability of Earth
temperature.
Current global warming is bringing an increase of global temperatures
that will impart changes to and in turn be affected by circulation
patterns in the atmosphere and ocean. Evidence grows of changes in
atmospheric weather patterns and in major ocean current systems.
This evidence indicates that these weather and ocean current
changes will have most dramatic effects in the Arctic.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 22 – Sea surface temperature and other sensible data
Sea surface temperature is most directly controlled by incoming solar
radiation, but is also strongly affected by vertical and horizontal ocean
circulation. NASA’s Earth Observatory website provides fascinating
multi-year animations of seasonally varying global net radiation, snow
cover, sea surface temperature, and other parameters that tend to
distinguish Arctic conditions
(http://earthobservatory.nasa.gov/GlobalMaps/).
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 23 – Sea Ice
Sea ice will be a major focus later in this course. Presence of sea ice is
certainly a polar distinction. Diminishing sea ice in the Arctic is a
prominent hallmark of global warming that has been highlighted in the
media and considered at length in international politics of recent
times.
Satellites monitoring of sea ice extent from space since 1979 shows
dramatic loss in the Arctic that overshadow a lesser gain in the
Antarctic. NASA (http://www.nasa.gov/content/goddard/nasa-studyshows-global-sea-ice-diminishing-despite-antarctic-gains/) and the
National Snow and Ice Data Center (NSIDC, https://nsidc.org/)
provide more information on these trends.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 24 – The Arctic Region
The Earth-Sun system geometry and solar heating consideration
distinguish northern latitudes, most notably at the Arctic Circle where
the Sun does not rise at winter solstice. Land areas north of this latitude
include the 8 countries of the international Arctic Council
(http://www.arctic-council.org/), a political organization currently
chaired by the US. Considerations by the Arctic Council of land
features, ecologies, and cultures has led to a less regular definition of
the Arctic shown by the red line on the slide.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 25 – Other Arctic Boundaries
Permanently frozen soil, or permafrost, is created in regions with an
annual average temperature below freezing. Permafrost is a
challenging land feature in the Arctic, so its wide-spread and
persistent presence is a mark of the Arctic region. Northern hemisphere
distribution of permafrost is shown on the left-hand map, with
distinctions of soil grain size and the fraction of frozen water in the
permafrost material. Ground frozen in the last major ice age still exists
well south of the Arctic Circle.
Land and ocean habitats vary with solar radiation, as well as with
irregularities induced by mountain ranges and circulation patterns of
the atmosphere and the ocean. Arctic regions classified primarily by
habitat characteristics include the High Arctic, Low Arctic, and SubArctic regions, as shown in the right-hand map of the slide.
The slide provides web links to more detailed information about these
alternate delineations of Arctic characteristics.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 26 – Arctic Ocean Bathymetry and General Circulation
The International Bathymetric Chart of the Arctic Ocean (IBCAO) initiative is to
develop a digital data base that contains all available bathymetric data north of
64° North, for use by mapmakers, researchers, institutions, and others whose work
requires a detailed and accurate knowledge of the depth and the shape of the
Arctic seabed. Initiated in 1997, this undertaking has so far engaged the volunteer
efforts of investigators who are affiliated with 24 institutions in 10 countries.
Arctic Ocean Basin: The chart reveals the Arctic Ocean Basin to be about 4000 km
across and divided into two major basins by the Lomonosov Ridge, which extends
from Greenland past the North Pole to Siberia. These basins are the Amerasian
Basin, with its Canadian Basin extension, and the Eurasian Basin.
The main connection with the World Ocean is between Greenland and
Spitzbergen, through the East Greenland Rift Basin over a sill depth of about 2600
m. The general Arctic Ocean pattern of surface circulation is clockwise in the
Amerasian and Canadian Basins, leading out to the East Greenland Current.
Surface currents in the Eurasian Basin are predominantly along its axis past the Pole
toward the East Greenland Current with typical speeds of 1 to 4 cm/sec. The sill
depth of the Atlantic connection between Spitzbergen, Franz Josef Land, and
Novaya Zemlya, is about 200 m. Other connections to the Atlantic through the
Canadian Archipelago are shallow and contorted with little actual exchange of
water.
Chukchi Sea: The Chukchi shelf is wide and shallow, averaging 50 m depth. The 85-
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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km-wide Bering Strait, at the southern limit of the Chukchi Sea, is the only connection
with the Pacific is about 45m deep. Bering Strait currents are typically northward at
speeds 30 - 40 cm/sec.
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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Slide 27 - Conclusion
We have reviewed basic definitions and information sources for Earth
coordinate systems, for some aspects of GPS satellite measurement of
position, and for choices of horizontal and vertical datums. We also
reviewed facts about the Earth-Sun system that lead to reduced solar
heating at high latitudes, a primary distinction of the Arctic domain.
Some measurable variables related to the consequences of reduced
solar radiation were introduced in this presentation.
This concludes the first of our Arctic Marine Domain Awareness short
course presentations. The following second presentation will discuss
Arctic Marine Weather and Sea State and the final presentation will
discuss Sea Ice.
This is Orson Smith, saying “Good-bye for Now.”
Presented by Orson P. Smith, PE, Ph.D.
Professor Emeritus, UAA Civil Engineering
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