ACCESS NUMBER: M14AC00016

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STUDY TITLE: Sea Level Measurements along the Alaskan Chukchi and Beaufort Coasts

REPORT TITLE: Sea Level Measurements along the Alaskan Chukchi and Beaufort Coasts

CONTRACT NUMBER: M14AC00016

SPONSORING OCS REGION: Alaska

APPLICABLE PLANNING AREA(S): Chukchi Sea

FISCAL YEAR(S) OF PROJECT FUNDING: FY 2014

COMPLETION DATE OF REPORT: 

COSTS: $72,178

PROJECT MANAGER(S): S.R. Okkonen

LEAD AUTHOR OF REPORT: S.R. Okkonen

AFFILIATION: University of Alaska Fairbanks

ADDRESS: 245 ONL Bldg., Fairbanks, AK 99775-7220

PRINCIPAL INVESTIGATOR(S): S.R. Okkonen

KEY WORDS: Sea Level, Chukchi, Beaufort, Elson Lagoon

BACKGROUND: The general and specific goals of this project collectively address the BOEM 

framework issue of improving understanding of the marine and coastal environments of the 

Chukchi and Beaufort Seas and the use of local boats and crews to deploy/recover the 

moorings meets the CMI objectives of engaging local communities to address issues of local 

and scientific interest.

OBJECTIVES: The general objective of this project was to deploy sea level recorders (pressure 

sensors) to acquire year-long (summer 2014 – summer 2015) records of local sea level at Pt. 

Hope, Pt. Lay, Wainwright, Barrow, and Kaktovik. These measurements, along with those 

acquired by NOAA gauges at Red Dog and Prudhoe Bay, were intended to address the specific 

goals of:

1) Improving our understanding of ocean circulation and improving computer models of ocean 

circulation in the Chukchi and Beaufort Seas;

2) Investigating relationships between landfast ice breakout events and sea level changes;

3) Assessing the effects of sea level changes on coastal erosion; and 

4) Obtaining data necessary for coastal protection and engineering design issues.

DESCRIPTION: Although sea level recorders were deployed near five Alaska communities, 

only the recorders deployed in Elson Lagoon near Barrow, Alaska were recovered. Year-long

(378-day) records of sea level derived from these pressure sensor moorings in Elson Lagoon 

were analyzed with companion sea level records acquired by NOAA tide gauges at Red Dog 

dock and Prudhoe Bay. Thirty-seven standard tidal constituents were fit in a least squares 

procedure to the sea level heights and the corresponding amplitudes and phases for these tidal 

constituents were derived for each of the five locations. A least squares procedure involving a 

cohort of semidiurnal constituents was used to investigate the impact of sea ice on the 

propagation of the semidiurnal tides in Elson Lagoon. Cross-correlation analyses were used to 

investigate relationships among wind forcing (local and remote), shelf waves, and non-tidal sea 

level. Correlation analyses were also employed to investigate the impact of sea ice on the 

propagation of non-tidal sea level signals in Elson Lagoon.

STUDY RESULTS: In Elson Lagoon, the amplitudes of the semidiurnal tides (M2, S2, and N2) 

are larger during the open-water season (mid-June to mid-October) than during the ice-covered 

season (mid-October to mid-June). The associated phases of the semidiurnal tides are very 

similar at the three Elson Lagoon sites during the open-water season, but phase differences 

increase as winter progresses and as sea ice grows thicker. 
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Non-tidal sea level signals are coherent from Red Dog dock along the southern Alaskan 

Chukchi coast to at least Prudhoe Bay along the central Alaskan Beaufort coast, a coastwise 

distance of ~950 km. These non-tidal signals are characteristic of shelf waves that are likely 

generated by winds in the Bering and Chukchi Seas. The speed at which these signals 

propagate along the coast does not exhibit much seasonal variability. However, the presence of 

ice cover significantly slows the propagation of non-tidal signals within Elson Lagoon. The slow 

propagation speed implies a very shallow layer of water (perhaps less than 1 m) beneath the ice 

by late winter. Breakup in Elson Lagoon follows the Meade River spring freshet. An apparent 

sea level bulge at the eastern end of Elson Lagoon in late May and early June suggests that 

Admiralty Bay-Dease Inlet can act as a temporary reservoir for the freshet.

SIGNIFICANT CONCLUSIONS:

 The presence of landfast sea ice slows both tidal and non-tidal sea level signals in Elson 

Lagoon. 

 Remotely forced shelf waves represent a significant contribution to non-tidal sea level 

along the Alaskan Chukchi and Beaufort coasts. 

 Non-tidal sea level variations in Elson Lagoon are best correlated with lagged, alongshore winds near Pt. Lay, Alaska.

 Eastern Elson Lagoon (Dease Inlet-Admiralty Bay) appears to serve as a temporary 

reservoir for the Meade River spring freshet.

STUDY PRODUCT(S): 

Okkonen, S.R. 2015. Sea Level Measurements along the Alaskan Chukchi and Beaufort 

Coasts. Oral presentation. University of Alaska Coastal Marine Institute Annual Research 

Review, January 2015, Anchorage, Alaska.

Okkonen, S.R. 2016. Sea Level Measurements along the Alaskan Chukchi and Beaufort 

Coasts. Poster presentation. Alaska Marine Science Symposium, January 2016, Anchorage, 

Alaska.

Okkonen, S.R. 2016. Sea Level Measurements along the Alaskan Chukchi and Beaufort 

Coasts. Oral presentation. University of Alaska Coastal Marine Institute Annual Research 

Review, January 2016, Anchorage, Alaska.

Okkonen, S.R. 2016. Sea Level Measurements along the Alaskan Chukchi and Beaufort 

Coasts. Final Report. OCS Study 2016-075. University of Alaska Coastal Marine Institute, 

University of Alaska Fairbanks and USDOI, BOEM, Alaska OCS Region.

Okkonen, S.R. and T. Sformo. 2017. Relationships among sea level, hydrography and 

circulation in coastal waters near Barrow, Alaska. Poster presentation. Alaska Marine Science 

Symposium, January 2017, Anchorage, Alaska.
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Figure 1: Communities near where pressure sensors were deployed (red stars). Locations of 

existing NOAA tide gauges (blue stars).