Using Video Imagery to Study Wave Dynamics: Isla Verde

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USGS scientists designed a video camera station to measure wave run-up and flooding in the Isla Verde Coral Reef Marine Reserve and on the shoreline adjacent to the Luis Muñoz Marin International Airport. The cameras, installed atop a building and overlooking this stretch of coast, collected a variety of imagery between November, 2018 through July, 2019. The imagery helps to show where waves break on the reef and how high they run up on the shore.

Currently, oceanographic instruments installed on the coral reef continue to measure wave heights and speeds.

As part of a study funded by USGS in response to Hurricanes Irma and Maria, USGS partnered with the National Oceanic and Atmospheric Administration (NOAA), the University of Puerto Rico-Mayaguez (UPR-M), and Arrecifes Pro Ciudad to better understand how waves propagate across coral reefs and cause coastal flooding along tropical shorelines. Their goal is to reduce hazards to, and increase the resilience of, tropical coastal communities. NOAA will use the study results to guide restoration of coral reefs and threatened coral species (Acropora spp., Dendrogyra cylindrus, Orbicella spp.). UPR-M will use the findings to improve coastal hazard forecasts they provide with data from NOAA’s Caribbean Coastal Ocean Observing System (CariCOOS). Arrecifes Pro Ciudad is a community-based effort to protect and restore the Isla Verde Coral Reef Marine Reserve. This urban reef supports various species of protected corals, sea turtles, and crustaceans, as well as many Caribbean fish. It also protects the International Airport and numerous homes and resorts on the coast.

Sources/Usage: Public Domain. View Media Details

Snapshots

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

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).

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.

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.

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.