noaa.gov
The nation's ocean and coastal agency: Supporting coastal communities, promoting a robust economy, and protecting coastal and marine ecosystems
a sunset beach a sunset beach with text 'ten dangers at the beach' a whale
A depiction of the United States geoid. Areas in yellow and orange have a slightly stronger gravity field as a result of the Rocky Mountains.
OCEAN FACT
What is the geoid?

The geoid is a model of global mean sea level that is used to measure surface elevations. While many think of the earth as a sphere, Earth is actually very bumpy and irregular.

More Browse All Facts

port
AUDIO PODCAST
Ocean Economy

Dive into our ocean economy in our latest podcast. We talk with NOAA economist Jeff Adkins to understand how we all benefit from our ocean economy.

Listen Browse Podcasts

coral
Education
Corals Tutorial

Attention students of all ages! Get an overview of the biology of and threats to coral reefs, as well as efforts being made to conserve and protect them with our newly-revised corals tutorial.

Tutorial NOS Education

container ships in San Francisco Bay
HSRP
Call for Nominations

Are you an ocean, coastal, or geodesy expert? NOAA is soliciting nominations for membership for the 2016 Hydrographic Services Review Panel, a Federal Advisory Committee.

Learn More

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.

Explore what we do

a yellow reef fish

Reef Etiquette

You can help protect coral reefs (even if you're not near the ocean). Take a look at this coral etiquette guide.

Continue Reading →

Bowling Ball Beach within Greater Farollones National  Marine Sanctuary

Sizeable Sanctuaries

Heard the news? Two of California's national marine sanctuaries more than doubled in size in June.

Continue reading →