No abstract

No abstract

The tide gage at Prudhoe Bay provides the only continuous long term direct measurement of sea level on the Alaska North Slope. In addition to trends in mean sea level, it provides a record of storm surges and setdowns. Analysis of the sea level time series from 1993 to 2010 reveals no statistically significant trends in relative sea level, storm frequency, intensity and duration. The return period of sea level extremes are estimated.

No abstract

No abstract

No abstract

Ice conditions were measured in Lower Cook Inlet, Alaska using Acoustic Doppler Profilers with an innovative data analysis method. PND Engineers, Inc., deployed three bottom-mounted upward-looking Nortek Acoustic Wave and Current (AWAC) profilers near Iniskin Bay. The instruments were configured to collect current profiles and wave data alternating with experimental “diagnostic” water-ice interface profiles. Analyzing these measurements together with the surface current velocity time series and assumed ice block shape allows estimation of the ice block size, mass, and velocity. Descriptions of the instrumentation and data processing are presented in this paper. This mission was the first application of this recently developed technique for ice measurements in Cook Inlet’s harsh environment.

Large-scale hydraulic model tests and detail numerical model investigations were conducted on recurved wave deflecting structures to aid in the design of wave overtopping mitigation for vertical walls in shallow water. The incident wave and storm surge conditions were characteristic return period events for an offshore island on the North Slope of Alaska. During large storm events, despite depth-limited wave heights, a proposed vertical wall extension was susceptible to wave overtopping, which could potentially cause damage to equipment. Numeric calculations were conducted prior to the experimental tests and were used to establish the relative effectiveness of several recurved parapet concepts. The numerical simulations utilized the COrnell BReaking waves and Structures (COBRAS) fluid modeling program, which is a Volume-of-Fluid (VOF) model based on Reynolds Averaged Navier-Stokes equations [1] [2]. The experimental testing was conducted in the Large Wave Flume (LWF) at Oregon State University, O.H. Hinsdale Wave Research Laboratory. The experimental test directly measured the base shear force, vertical force, and overturning moment applied to the recurved parapets due to wave forcing. Wave impact pressure on the parapet and water particle velocities seaward of the wall were also measured. Results from the experimental testing include probability of exceedance curves for the base shear force, vertical force, and overturning moment for each storm condition. Qualitative comparisons between the experimental tests and the COBRAS simulations show that the numerical model provides realistic flow on and over the parapet.