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Preliminary wave energy hindcast results for the circum-arctic region. David E. Atkinson International Arctic Research Center / Atmospheric Sciences Department University of Alaska Fairbanks. AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005.
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Preliminary wave energy hindcast results for the circum-arctic region • David E. Atkinson • International Arctic Research Center / Atmospheric Sciences Department • University of Alaska Fairbanks AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005
To begin with: > Understand the impact of waves > Understand the importance of storms - to drive waves - to drive surges Examine storm climatology results AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005
AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 Atlantic track is prominent at circum-polar scale David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Results from Arctic Coastal Dynamics project ACD zones, weather station locations AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
3 Storm counts 2 4 1 5 7 6 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Trends in storm counts - no strong trend David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Other influences on coastal erosion • In frozen regions must consider • Sea ice • Permafrost AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005
Melt season increasing Reduced sea ice cover Trends in open water season length, 1950 - 2000 (model initialized with observations) AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Results from western Kara Sea coast (S. Ogorodov, Moscow State University) - influence of wave energy and temperature in permafrost coastal zones AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005
Wave energy climatologies - impetus > Wave energy principle forcing agent > Much of the circum-polar (AK) coastal zone susceptible to erosion > 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) > Coastal process models require wave energy input (I.e., and not wind) > Engineering issues AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Scope and Approach Desire: develop a system that will translate winds into wave energy • Driving winds – gridded is desirable - North American Regional Reanalysis for AK (32 km) - AOGCM for work with prediction scenarios > 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 AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Scope and Approach Wave energy calculation - 1st order linear (Airy) approximation > Coastal Engineering Manual and Technical Reference for the Automated Coastal Engineering System (USArmy Corps of Engineers) > suitable for most applications > Represents a starting point only AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
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 AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
NCEP/NCAR Reanalysis wind speed problem AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 0.7
NCEP/NCAR Reanalysis wind speed problem AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 0.7
Scope and Approach Depth - simply specified at 10m - represents generic shelf zone Sea ice - NSIDC extent plots used - based on ice plots: > coastal region divided into 12 sectors by longitude > sectors assigned a binary ice/no ice class - turned energy on/off for that month AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
3 2 4 5 1 6 7 8 9 10 11 12 Results from Arctic Coastal Dynamics project ACD zones, weather station locations AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
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 (hemisphere approach) AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
1979 total ICE No ICE David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
1998 total ICE No ICE David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
1979 – 2003 mean ICE No ICE David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
1979 – 2003 trends ICE No ICE David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Next steps/improvements > Increase wind forcing resolution > Introduce local coastal orientation > Variable depth > Introduce variable ice concentrations, drop sector approach > Comparisons with existing observed/modeled information (e.g. Ogorodov for Pechora Sea) AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks
Conclusions from storm and wave energy work: > Trends in (circumpolar) storminess not simple linear > Ice (marine and terrestiral) must be explicitly considered for erosion work > Influence of sea ice for wave energy apparent even for this coarse approach > Wave energy trends, not just seasonal totals, influenced by sea ice conditions AK PRIDE wind/wave climatology workshop Hotel Captain Cook, Anchorage, August 2-3, 2005 David E. Atkinson IARC/Atm. Sci., University of Alaska Fairbanks