Developing WindWave Hindcast

1
Developing Wind/Wave Hindcast Climatologies for
Alaska
David E. Atkinson International Arctic Research
Center / Atmospheric Sciences Department Universit
y of Alaska Fairbanks James Partain National
Weather Service, Alaska Region Headquarters NOAA
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
2
Research results Storm climatology Wave
climatology development gt assumptions gt sea
ice gt gridded data probs with NNR gt
results Response to CERB objectives gt coastal
erosion activities PRIDE workshop and
initiatives for AK HI gt climate change
impacts Federal initiative currently under
consideration
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
3
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
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
4
Impetus
Interest in waves gt Coastal dynamics driven in
large measure by energy input from
waves Interest in climatologies gt Relate
existing coastal change to existing trends in
wave energy gt Predict possible future trends
Coastal dynamics implications gt Mineral sediments
and carbon moved to ocean gt Terrestrial, marine
ecology impacted gt Human habitation,
infrastructure, way of life disrupted
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
5
NWS Alaska Region Climate Challenges

• Climate change in Alaska is WAY beyond academic
• Decades-old warming at locations all across
  Alaska
• Greatly reduced extent and thickness of
  multi-year sea ice
• Later freeze-up in Fall and earlier break-up in
  Spring
• Glaciers retreating, Permafrost melting with
  attendant issues
• For NWS, debate over cause of warming is moot
  NWS weather customers are impacted on a daily
  basis they are looking to us for expertise!

6
The Bering Sea Storm Oct 18-20, 2004

• Greatest short-term weather impacts of climate
  change are for coastal storms and attendant
  erosion
• Later freeze-up, less extent and thinner sea-ice,
  combined with loss of coastal permafrost, is a
  recipe for erosion from normal Fall storms
• Impacts magnified by greater wave size due to
  increased open-water fetch
• Dozens of Alaskan coastal communities currently
  experiencing significant erosion7 communities
  are critical, and 3 are in imminent peril of
  being washed away (Shishmaref, Newtok, Kivilina).

7
The Bering Sea Storm Oct 18-20, 2004

• Most important contributions from NWS are
  Accuracy and Lead Time
• The bomb of October 18-20, 2004, illustrates
  the potential of our contributions
• An ex-tropical cyclone rapidly deepened over a
  period of several days to 940mb
• Such storms normally handled very poorly by the
  models, even in the short-term
• In this case, GFS had large-scale details,
  including amplification and track, predicted at
  5-days lead time
• More importantly, run-to-run consistency was key
  to forecaster confidence in forecast/warning
  issuances.

8
Bering Sea storm October 19, 2004
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
9
Bering Sea storm October 19, 2004
SLP
10
Atlantic hurricanes, 2003 season
11
The Bering Sea Storm Oct 18-20, 2004

• Lead-time from WFO Fairbanks with first products
  was 60-hrs
• Emergency managers were in continuous contact
  with WFO Fairbanks and the WSOs in Nome and
  Kotzebue before, during and after the event
• MDLs storm surge guidance also quite accurate
  and useful both to NWS staff and EMs
• Evacuations took place and physical mitigations
  were put in place for structure protectionno
  loss of life or significant injuries resulted.

12
The Bering Sea Storm Oct 18-20, 2004

• Stillmuch erosion and property damage occurred
• 30M damage in Nome alone
• 50 feet of shoreline lost in Shishmarefthey
  will not survive another such storm
• Congress is looking at relocating imperiled
  villagesan extremely expensive proposition
• This storm showed
• The value of accurate, consistent objective
  guidance in improving forecaster confidence in a
  developing storm
• The value of lead time
• The value of NWS information to emergency
  planners for disaster mitigation.

13
Nome, AK during the storm
14
Nome, AK Front Street (where the Iditarod
finishes)
15
A residence in Shishmaref, AK after the storm
16
The Shishmaref school after the storm
17
Mechanisms
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
18
Impacts
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
19
Impacts Alaska - communities
The following communities are directly threatened

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
20
Impacts Alaska - communities
Figure given to me by Tohru Saito, IARC
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
21
Thus
gt Understand the impact of waves gt Understand the
importance of storms - to drive waves - to
drive surges Examine storm climatology results
22
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
Atlantic track is prominent at circum-polar scale
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
23
Results from Arctic Coastal Dynamics project
ACD zones, weather station locations
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
24
3
Storm counts
2
4
1
5
7
6
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
25
Trends in storm counts
- no strong trend
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
26
Other influences on coastal erosion

• In frozen regions must consider
• Sea ice
• Permafrost

27
Trends in open water season length, 1950 -
2000 (model initialized with observations)
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
28
Results from western Kara Sea (S. Ogorodov,
Moscow State University) - influence of
temperature and wave energy in permafrost zones
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
29
Wave energy climatologies - impetus
gt Wave energy principle forcing agent gt Much of
the circum-polar coastal zone susceptible to
erosion gt Problem is not easy various
parameters that must be considered - shallow
zones - sea ice ice on/off dates controls
wave access position of ice offshore controls
fetch (presence of floating ice also modifies
wave energy) gt Coastal process models require
wave energy input (I.e., and not wind) gt
Engineering issues
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
30
Scope and Approach
Desire develop a system that will translate
winds into wave energy gt ERA is available, but
- custom development will allow tailoring
(e.g. force with winds from HIRHAM, upcoming
arctic reanalysis, even AOGCM predicted
fields.) gt Generate climatological wave
fields - monthly totals - annual totals -
period means and trends (1979-2003) Provide to
coastal dymanics researchers, but can also
assess contribution of ice
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
31
Scope and Approach
Wave energy calculation - 1st order linear
(Airy) approximation gt Coastal Engineering
Manual and Technical Reference for the
Automated Coastal Engineering System (USArmy
Corps of Engineers) gt suitable for most
applications Full complexity of the 3-D fluid
structure can not currently be described in its
entirety
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
32
Scope and Approach
Wind forcing - NCEP/NCAR reanalysis, 925 mb to
overcome speed problems - direction limited to
180 (I.e. water side) Direct forcing approach,
not distribution based
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
33
NCEP/NCAR Reanalysis wind speed problem
34
NCEP/NCAR Reanalysis wind speed problem
35
Scope and Approach
Depth - simply specified at 10m - represents
generic shelf zone Sea ice - NSIDC extent plots
used - coastal region divided into 12 sectors by
longitude - based on ice plots, sectors assigned
a binary ice/no ice class - turned energy on/off
for that month
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
36
NSIDC Sea Ice extent from passive microwave
37
Results from Arctic Coastal Dynamics project
ACD zones, weather station locations
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
38
Limitations
No depth variation Winds do not catch all events
(spatial resolution) Ice sector
approximation Ice content (binary approach)
coarse Spatial resoution coarse Orientation of
wind energy wrt coastline crude (180 degree thing)
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
39
1979 total
ICE
No ICE
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
40
1998 total
ICE
No ICE
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
41
1979 2003 mean
ICE
No ICE
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
42
1979 2003 trends
ICE
No ICE
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
43
Next steps/improvements
gt Increase wind forcing resolution gt Introduce
local coastal orientation gt Variable depth gt
Introduce variable ice concentrations, drop
sector approach gt Comparisons with existing
observed/modeled information (e.g. Ogorodov
for Pechora Sea)
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
44
Conclusions
gt Influence of sea ice apparent even for this
coarse approach gt Wave energy trends, not just
seasonal totals, influenced by sea ice conditions

79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
45
Coastal Dynamics as a Function of Environmental
Forcing and Coastal Geology/Geocryology
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
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)
46
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
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
47
Ice push Figures courtesy Patrick Lajeunesse,
Université Laval, Québec
48
Ice push Figures courtesy Patrick Lajeunesse,
Université Laval, Québec
49
Impacts Alaska - communities
Shishmaref bluff retreat
Photos by Julie Baltar , story in the Nome
Nugget Shishmaref, AK
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
- ecological systems threatened - way of life
threatened
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
50
Notice taken at highest levels
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
51
Coastal erosion - forcings
High winds gt storms gt stalled 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)
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
52
3
3
3
2
Storm mean speed
4
1
5
7
6
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
53
3
Storm duration
2
4
1
5
7
6
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
54
3
Storm mean power
2
4
1
5
7
6
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
55
And so
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
Now what?
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
David E. Atkinson IARC/Atm. Sci., University of
Alaska Fairbanks
56
Solutions?
Two choices gt fight the sea gt run from it
Recall the interrelatedness of the coastal system
79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
57
Sea walls at Homer, Shishmaref
Moving a village is a very expensive option

• perhaps can work with and within the existing
  environmental context
• potential at Shishmaref ?

79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
58
In summary

• Coastal erosion potential is increasing
• Problem isnt going to go away
• But instead of the more heavy handed
  (traditional?) engineering solutions, perhaps
  work more with the context
• requires greater understanding of how the arctic
  coastal system functions
• inputs from TK and from research
• CERB messages coast as a system, must integrate
  various process trajectories to arrive at
  resultant impact for coastal system (eg sea ice
  and storm trends)

79th Coastal Engineering Research Board
meeting Egan Center, Anchorage, June 7-9, 2005
59
Specification of wave energy

• Basic energy equation
• Define H and L in terms of U and F
• Returns energy for a given point