noaa.gov
The nation's ocean and coastal agency: Supporting coastal communities, promoting a robust economy, and protecting coastal and marine ecosystems
a glacier monk seal on a net
USS New York going under a bridge
OCEAN FACT
What is air gap?

The NOAA Air Gap system is a tool that measures the clearance between the water surface and the bridge. Air gap measurements are updated every six minutes.

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DART real-time tsunami monitoring systems
AUDIO PODCAST
Tsunamis

A tsunami is a series of ocean waves caused by the displacement of a large volume of water. Explore what causes a tsunami in our latest Ocean Shorts podcast.

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About NOS

We translate science, tools, and services into action to address threats to coastal areas such as climate change, population growth, port congestion, and contaminants in the environment—all working towards healthy coasts and healthy economies.

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Explore what we do

a NOAA ROV

Pressure Drop

How does pressure change with ocean depth? At sea level, the air that surrounds us presses down on our bodies at 14.5 pounds per square inch. You don't feel it because the fluids in your body are pushing outward with the same force.

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surveyor in silhouette

Survey says!

From the survey marker on your street to the transit of goods on our maritime highways to even landing safely after your next flight, we need surveys. NOS is responsible for many of the surveys we rely on every day.

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