Sargassum is a type of floating brown algae, commonly called “seaweed.” These algae float at the sea surface, never attach to the sea floor, and they can aggregate to form large mats in the open ocean.

Researchers at NOAA’s AOML and NOAA’s National Environmental Satellite Data, Information Service (NESDIS), and the University of South Florida developed the experimental Sargassum Inundation Report (SIR) to provide an overview of the extent of Sargassum in the ocean and the risk of Sargassum washing into coastal waters, beaches, and shorelines in the Caribbean, Gulf of Mexico, and southeast Florida regions.

Research conducted at AOML in partnership with the University of Miami, the University of South Florida, and LGL Ecological Research (TX) is also aiding to identify how Sargassum extends across the Caribbean, Gulf of Mexico, and tropical Atlantic, by assessing the role of ocean currents, winds, and waves in their motion.  This work includes field experiments conducted to monitor the actual path of Sargassum using satellite tracking devices and surface drifters and satellite imagery, and physical representation of Sargassum in theoretical and numerical simulations. Please refer to the end of this document for a list of scientific manuscripts derived from this research.

Additionally, a collaboration between researchers with AOML and Fearless Fund studies how seaweed, including Sargassum, naturally removes carbon dioxide from ocean waters and sequesters it in the seaweed. This project seeks to provide a management solution to wide-scale inundation of beaches, while also repurposing the Sargassum.

Further reading:

Tracking Sargassum Inundation Potential for Coastal Communities – NOAA/AOML

Chasing Sargassum: New Insights on Coastal Sargassum Invasions – NOAA/AOML

The motion, extent, and density of Sargassum is very complex – it grows, sinks, and moves according to ocean currents, winds, and waves. Therefore, sometimes it may not be possible to describe trajectories in advance, but rather a general description of how the average extension and density have changed.  Projecting an accurate path of Sargassum is challenging and a current area of intense research.  At this moment, the timing of Sargassum beaching cannot be predicted.

There are two main sources of Sargassum located in the Gulf of Mexico, one is local and peaks in April-May, and the second one is the Caribbean Sea which peaks during the summer months. Large amounts of Sargassum are currently located in the Caribbean Sea, moving towards the Yucatan Peninsula, and spreading through the Gulf of Mexico by the Loop Current.

The Loop Current flows through the Florida Straits and off the east Florida coast, where it is known as the Florida Current, and into the Gulf Stream as it heads north up the eastern coast of the US.  The very strong Loop Current is now transporting moderate amounts of Sargassum that were previously located in the Caribbean Sea, with larger amounts potentially on the way. Some of the Sargassum in the Gulf of Mexico also originated locally. Whether the Sargassum will beach on the coast of Florida, including the Florida Keys, will largely depend on the local wind, wave, and tide conditions. Given the complexity of its motion, growth, and decay, it is not possible to forecast the timing of beaching.  However, given the size and number of the current Sargassum patches, there is a strong chance that Sargassum carried by the Florida Current may reach the Florida coast despite wind and wave conditions. As of mid March 2023, satellite observations indicate that some of this Sargassum has already reached the northern coast of Cuba.

Maps showing Sargassum patches as derived from satellite images and reported weekly through the AOML experimental Sargassum Inundation Reports (link)

The amount of energy that a storm produces far outweighs the energy produced by one nuclear weapon. Additionally, the downside of radioactive fallout from such an operation would far outweigh the benefits and may not even alter the storm.

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The energy released from a hurricane can be explained in two ways: the total amount of energy released by the condensation of water droplets (latent heat), or the amount of kinetic energy generated to maintain the strong, swirling winds of a hurricane. The vast majority of the latent heat released is used to drive the convection of a storm, but the total energy released from condensation is 200 times the world-wide electrical generating capacity, or 6.0 x 10¹⁴ watts per day. If you measure the total kinetic energy instead, it comes out to about 1.5 x 10¹² watts per day, or ½ of the world-wide electrical generating capacity. It would seem that although wind energy seems the most obvious energetic process, it is actually the latent release of heat that feeds a hurricane’s momentum.

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The tropical atmosphere is often unstable.  The amount of energy accumulated in the lower layers though the evaporation of water eventually overcomes any stable cap.  This allows clusters of thunderstorms to form.  These clusters move along with the prevailing winds as tropical disturbances.  Occasionally, cyclonic circulations will develop within these disturbances.  These circulations can be amplified and the disturbance will form a tropical cyclone.  Only about 10% of disturbances become tropical cyclones, so large-scale influences impinging on such disturbances play a big role in cyclone formation.

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A hurricane is usually a symmetrical spiral.  But if it is moving forward, then this motion makes the wind field asymmetrical.  The side of the spiral with winds blowing in the direction of movement will add the forward speed to the wind speed. The side of the spiral with the wind blowing in the opposite direction will be subtract the forward speed from the wind speed.

For example, a hurricane with 90mph winds moving forward at 10mph would have a 100mph wind speed on the forward-moving side and 80 mph on the side with winds blowing backward to the motion.

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Names are assigned to organized tropical cyclones once their winds exceed 39 mph (17.5 m/s, 34 knots).  The names are drawn from a list that is created prior to the season by the United Nations’ World Meteorological Organization.  Each tropical cyclone basin has its own name list, which is maintained by a WMO Regional Committee. If a particularly damaging storm occurs, the name of that storm can be retired.  If a storm happens to move across basins, it keeps the original name. The only time it is renamed if it dissipates to a tropical disturbance and then reforms.

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