Tag: Basics

Natural History / Natural History - 5 years ago

What is ocean acidification?

What is ocean acidification? Watch our video for a quick overview. For more than 200 years, or since the industrial revolution, the concentration of carbon dioxide (CO2) in the atmosphere has increased due to the burning of fossil fuels and l...

Natural History / Natural History - 6 years ago

What is a perigean spring tide?

About three or four times a year (in the spring and the fall), the new or full moon coincides closely in time with the perigee of the moon—the point when the moon is closest to the Earth. These occurrences are often called 'perigean spring tides....

Natural History / Natural History - 6 years ago

How big is the Atlantic Ocean?

As the second largest ocean basin, the Atlantic Ocean borders the east coast of the U.S., while the Pacific, Earth's largest ocean basin, borders the U.S. West Coast. Covering approximately 20 percent of the Earth’s surface, the Atlantic Ocean...

Natural History / Natural History - 6 years ago

What is a datum?

Near coastal areas, mean sea level (and other tidal datums) is determined by analyzing observations from a tide gauge. This image shows a tide gauge at the St. Charles Parish Water Level Monitoring System in Louisiana. A geodetic datum is an a...

Natural History / Natural History - 6 years ago

What is an iceberg?

Iceberg located in Ross Sea, Antarctica. To be classified as an iceberg, the height of the ice must be greater than 16 feet above sea level and the thickness must be 98-164 feet and the ice must cover an area of at least 5,382 square feet. The...

Natural History / Natural History - 6 years ago

What is the geoid?

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. While we often think of the earth as a sphere, our planet is actually very bumpy and irregular. The r...

Natural History / Natural History - 6 years ago

What is the law of the sea?

NOAA's nautical charts provide the baseline that marks the inner limit of the territorial sea and the outer limit of internal waters. This determines where U.S. territorial waters begin for purposes of international law. Notable in the develop...