Government-funded researchers from Colombia have been using wave and ocean current data measured by sensors from Nortek, a Norwegian acoustic Doppler instrumentation specialist, to improve hurricane prediction.
Colombia’s Caribbean islands were devastated by hurricanes Eta and Iota within a two-week period in November 2020. With a total of 14 hurricanes, 2020 was the most active Atlantic hurricane season to date.
The experience of Eta and Iota prompted the authorities on the Archipelago of San Andrés, Providencia and Santa Catalina to request help from the Universidad Nacional de Colombia and the regional environmental protection agency, CORALINA, to develop tools to plan and prepare for future events, including computer modeling to better predict hurricane risk.
Dr Andrés Fernando Osorio Arias, professor at the Universidad Nacional de Colombia and executive director of the Center of Excellence in Marine Sciences (CEMarin), said, “We use these models to create reconstructions of hurricanes that have occurred in the past, and also to predict scenarios that have not yet occurred – synthetic scenarios of hurricanes.”
While such models are generally robust, their accuracy is improved by comparison with data measured from the field. This is particularly important as biophysical features such as coral reefs, mangroves and seagrasses can influence sea conditions around islands.
“It’s important to collect information from the field and try to reproduce conditions on a laboratory scale because, in the laboratory, you have more control of the different factors,” he added. “With field and laboratory data, you can develop new equations, new parameters and new physical understanding of physical processes to improve the models.”
The scientists gather real-world data on current and wave direction using two AWAC subsea sensors made by Nortek. These record the motion of the water using calculations based on the Doppler effect. The sensors emit sound waves, then measure the echoes that return after bouncing off particles suspended in the water. As waves travel horizontally, these move with the water in a circular, or orbital, motion. This provides insight into how the height and direction of waves varies according to weather conditions.
Cristobal Molina, senior sales engineer for Latin America and Mediterranean, said, “The waves on the surface are a combination of many waves, which have different directions, periods and heights. The AWAC acoustic sensor takes measurements over a long period, allowing us to discriminate between the different waves.”
Having validated the model with the real-world data from Eta and Iota, the researchers can now confidently create synthetic hurricane scenarios to identify the areas of the islands that are most vulnerable to flooding. As a result, the authorities can take action to protect vulnerable communities, such as planting seagrass in strategic locations.