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Know Your Earth 3.0: Jason-3
04.01.13
 
Jason-3 banner with Josh Willis

About Josh Willis


Josh Willis is the project scientist for NASA's Jason-3, and works with both the engineers who build the satellite and the scientists who use the data to make sure that Jason-3 will measure sea level as accurately as its predecessors. Satellites like Jason-1, Jason-2 and soon Jason-3 can measure changes in globally averaged sea level with an accuracy of about four millimeters, or about an eighth of an inch. They do this from more than 826 miles, or 1330 kilometers above Earth's surface.

Willis earned his doctorate in oceanography from Scripps Institution of Oceanography. While there, he studied how the ocean warms and how it contributes to global sea level rise. In 2004, Josh joined NASA's Jet Propulsion Laboratory and began to study other causes of sea level rise, like the melting of the great ice sheets in Greenland and Antarctica. Locked away in these giant "ice cubes" is enough water to raise global sea levels by 250 feet (76.2 meters), but the question remains of how fast they will melt in our warming world. Most scientists predict that we will not see more than six feet (1.8 meters) of sea level rise by the year 2100, but six feet (1.8 meters) could spell disaster for coastlines all around the world. No matter how much sea levels rise, NASA satellites will continue to be our most important tool for observing it.

Along with his fellow scientists, Willis continues to monitor the rise in global sea levels, which is the direct result of human-caused warming of Earth's climate. Today, the rate of global sea level rise is a bit faster than an inch per decade. But if the ice sheets begin to melt more quickly, the rate of sea level rise could easily double or triple. Willis believes the Jason satellites will provide the first evidence of such global changes, if and when they occur.

When he's not studying the ocean, Willis likes to take trips to Las Vegas with his wife. He also enjoys improvising at The Second City in Hollywood and making occasional contributions to the comedy podcast "Funny Cuz It's True" on iTunes. Someday, he hopes to bring humor to the public discourse on climate change. Scientists predict this will happen when penguins fly.

About Jason-3


Artist's concept of the Jason 3 spacecraft

An artist's rendering of the Jason-3 satellite.
Credit: CNES, CLS
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With a planned launch in early 2015, Jason-3 will continue the accurate measurement of global sea surface height from space, which began in 1992 with Topex/Poseidon, and continued with Jason-1 in 2001 and Jason-2 in 2008.

Based on the more than 20-year record of sea surface height measurements from satellites, coupled with a long-term record of increasing atmospheric carbon dioxide concentrations and global temperature records, scientists can conclude that rising sea level is the direct result of human-caused warming of Earth's climate. Today, the precise rate of global sea level rise as measured from space is 1.3 inches (33 millimeters) per decade. But if the ice sheets should begin to melt more quickly, the rate of sea level rise could easily double or triple. The Jason satellites are expected to provide the first evidence of such global changes, if and when they occur.

Topex/Poseidon and Jason-1 are joint missions between NASA and Centre National d'Etudes Spatiales (CNES) French Space Agency. Jason-2 is a four-member, international partnership between NASA, CNES, the National Oceanic and Atmospheric Administration (NOAA), and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).

Additional Links


› Know Your Earth 3.0
› Jason-3 Mission
› Global sea level rise
› JPL Jason-3 mission page