Kein Folientitel

1
Circumpolar storminess and impacts on coastal
erosion
David E. Atkinson International Arctic Research
Center / Atmospheric Sciences Department Universit
y of Alaska Fairbanks
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
2
Coastal erosion

• Alteration of the coastal regime
• gt usually involves removal of material
• gt can include reworking shifting bars or spits
• gt coastline dynamics and morphodynamics
• gt can include flooding

• Implications
• gt Mineral sediments and carbon moved to ocean
• gt Terrestrial, marine ecology impacted
• gt Human habitation, infrastructure, way of life
  disrupted

Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
3
Coastal Dynamics as a Function of Environmental
Forcing and Coastal Geology/Geocryology
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
Figure by Volker Rachold, Alfred Wegener
Institute, Potsdam, Germany
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
IASC Council Meeting at ASSW 2003 (Kiruna, Sweden)
4
Coastal erosion - mechanisms
gt waves gt currents gt normal thermal stress on
frozen environments - sediment collapse - ice
wedge/thaw planes gt sea ice - ice shoves -
freezing entrains sediments gt surges - water
level - water level waves
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
5
Mechanisms
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
6
Impacts
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
7
Impacts Alaska - communities
The following communities are directly threatened
and must be moved
Bluff and seawall defense at Homer, AK Picture
from High School project by Monica PetersNat
SeamanJoleena BaughKirsten Baltz 2003, Homer
High School
Homer (Katchemak Bay/Kenai) Newtok
(Kenai) Shishmaref (Seward) Point Hope (North
Slope /Lisburne Peninsula) Kivalina (North
Slope/Lisburne Peninsula) Barrow (North Slope)
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
8
Shishmaref bluff retreat
Photos by Julie Baltar , story in the Nome
Nugget Shishmaref, AK
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
9
Notice taken at highest levels
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
10
Coastal erosion - forcings
High winds gt storms gt pressure gradient
events Ice marine and terrestrial and threats
to it gt effects on sediments gt sea ice -
distance from coast - open water season
length Warming temperatures (ice)
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
11
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
Atlantic track is prominent at circum-polar scale
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
12
Results from Arctic Coastal Dynamics project
ACD zones, weather station locations
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
13
3
Storm counts
2
4
1
5
7
6
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
14
3
3
3
2
Storm mean speed
4
1
5
7
6
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
15
3
Storm duration
2
4
1
5
7
6
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
16
3
Storm mean power
2
4
1
5
Large erosive potential on Alaskan Chukchi coast
7
6
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
17
Trends in storm counts
- no strong trend
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
18
Trends in open water season length, 1950 -
2000 (model initialized with observations)
Melt season increasing Reduced sea ice cover
Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
19
In summary

• gt Coastal erosion strongly dependent on forcing
• gt Currently making impact felt human and
  ecosystem
• gt Chukchi Sea region can see strongly erosive
  storms
• gt storminess trends not conclusive, but sea ice
  retreat problematic

Arctic Division AAAS 55th Annual
meeting Anchorage, Alaska
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks