Using Video Imagery to Study Wave Dynamics: Unalakleet

Science Center Objects

Two video cameras overlook the coast from atop a windmill tower in Unalakleet, Alaska where they look westward over Norton Sound.

Circular logo with lettering around the perimeter, graphics in the center are a compass and rock pick on the outline of Alaska.

The village of Unalakleet is established on a low-lying barrier spit at the eastern end of Norton Sound at the mouth of the Unalakleet River. The region is vulnerable to marine flooding during large storm events. Storm surge in Norton Sound typically occurs in the fall and winter months when the coastline is protected by shorefast ice. Warming trends in the Arctic have resulted in reduced ice coverage and increased occurrence of wave events impacting coasts. This camera system was installed by the USGS in collaboration with Alaska DGGS (Department of Natural Resources, Division of Geological and Geophysical Surveys), the Native Village of Unalakleet, and the City of Unalakleet to better understand wave and water-level dynamics in Norton Sound.

Every half hour during daylight hours, the cameras collect snapshots and video for 10 minutes. Today’s most recent images are shown below. Please note that it takes 10 minutes for the images to be posted, once they are collected by the camera.

These and other images are used to observe and quantify coastal processes such as wave run-up, development of rip channels, bluff erosion, and movement of sandbars and ice floes.

Circle with artistic rendition of a bird flying in the center, with the letters N-O-A-A above the bird.

For water level and meteorological observations at the Unalakleet station, visit the NOAA Tides & Currents site.

USGS plans to install similar systems in other U.S. locations. The knowledge gained will improve computer-derived simulations of shoreline change that communities can use to plan for sea-level rise, changing storm patterns, and other threats to coasts.

Currently, video cameras are installed at these locations:

Please note: If old photos are displayed, cameras may be temporarily offline.

Snapshot

The snapshot is the first frame of the video, just like a standard photo.

Camera 1 Snapshot

Camera 2 Snapshot

 

Timex (time-exposure) images

A timex is a time-averaged image of all frames, smoothing away surface waves and determining the location of persistent wave-breaking (indicative of shallow sandbars).

Camera 1 Timex Image

Camera 2 Timex Image

 

Variance images

A “variance” image shows the standard deviation of pixel intensity throughout the video, and it is useful for determining how much variation or movement is occurring at a given location.

Camera 1 Variance Image

Camera 2 Variance Image

 

Bright images

A “bright” image shows the brightest pixel values throughout the video, useful for identifying the position of maximum wave run-up on the beach, position of all breaking waves, and sea-state.

Camera 1 Bright Image

Camera 2 Bright Image

 

Dark images

A “dark” image shows the darkest pixel values throughout the video, useful for tracking sediment plumes, tracking floating debris, and filtering out breaking waves.

Camera 1 Dark Image

Camera 2 Dark Image

 

View from the sky of a marsh with many sinuous channels near larger body of water, the spit of land on the right has buildings.

Unalakleet village on the low-lying barrier spit at the inlet of the Unalakleet River and Norton Sound, Alaska. 
Photo Credit: Shawn Harrison, USGS