Scientists at NASA's Jet Propulsion Laboratory are teaming up with European researchers to launch a mission that will investigate the depths of the oceans over the next decade – and chart their inexorable rise.
O Mission Sentinel-6 / Jason-CS It is based on four previous satellites that have been circling the globe along the same path since 1992, carefully documenting sea-level changes millimeter by millimeter fueled by greenhouse gas emissions. Over that time, they have found that the world's oceans are rising at an ever faster rate.
Rising waters have had some disastrous consequences, including erosion of precious shorelines, contamination of farmland, the most frequent and destructive high tides, and lost habitat for humans and wildlife.
Jason satellites, along with complementary readings from other NASA missions, were essential in tracking these changes and dealing with their consequences, he said. R. Steven Nerem, professor of aerospace engineering science at the University of Colorado Boulder and NASA member Ocean Surface Topography Science Team.
"Without satellites, we would be blinded," said Nerem, who has been tracking sea levels and their causes for decades. "It is very critical that we continue these missions because it is the way we understand what is going on."
Earth's oceans have waxed and waned for ages, but they usually do so very gradually, instead of the mind-blowing pace recorded today.
Recent readings estimate the rate at about 4.5 millimeters a year, up from 3 millimeters a year in 2005 and 2 millimeters a year in 1993. Add everything and the seas are now about five centimeters higher on average than which were a quarter of a century ago.
The question that the new Sentinel-6 / Jason-CS mission will seek to answer is: How much faster will the seas rise over the next decade? And what will happen to the earth after that?
"Hundreds of millions of people around the Earth will be affected by rising sea levels over the next 50 to 100 years, and our ability to measure how much of this is caused by humans is really rooted in these satellites," said JPL climate scientist. Josh Willis, NASA Project Scientist for Jason-CS.
Since the beginning of the industrial age, humans have emitted excessive amounts of carbon dioxide and other heat-trapping gases, causing the Earth's temperature to rise. Melted glaciers added water to the oceans. The additional heat also causes the water to expand, further raising sea level.
In total, the oceans absorbed more than 90 percent of the extra heat trapped by greenhouse gases, Willis said.
And because they cover more than two-thirds of the earth's surface, the oceans are reshaping the planet.
"The oceans, in a really big way, are our most important indicator of how much humans have changed the climate since the beginning of the industrial revolution," said Willis.
From an orbit 830 miles above Earth, Sentinel-6 / Jason-CS will examine 95% of the planet's ice-free oceans, gathering a new global data set every 10 days. Your altimeter will emit a radar signal from the water surface, measuring the time required for the signal to return and using this information to calculate the height of the ocean.
Other instruments improve these readings by compensating for the weather effect of these radar signals and helping to track the precise position of the probe.
The first Sentinel spacecraft in a clean room in Germany. The satellite is scheduled to be launched in November.
In addition to mean sea level, radar readings will provide a wealth of additional information for researchers who can use it to determine high ocean heat changes, ocean current flow, wave height and wind speed over water. .
The data may even shed light on much of the still mysterious seabed topography, said Eric Leuliette, the Jason program and project scientist for the National Oceanic and Atmospheric Administration.
"As my colleagues here often point out, we map Venus, the Moon, and Mars better than we map the ocean floor," he said.
Jason's dice hit the floor, Leuliette said. Within hours, it is sent to meteorologists of the National Weather Service, whose forecasts are used by ships for navigation and other maritime purposes. Within a day, he goes into models that help meteorologists make better predictions about major weather events. For example, the information Jason collects about the amount of heat stored beneath the ocean surface can help predict the intensity of a hurricane or the strength of an El Niño event.
Sentinel-6 / Jason-CS is part of an international collaboration involving NASA, NOAA, the European Space Agency, the European Organization for the Exploration of Meteorological Satellites (EUMETSAT) and the French National Center for Space Studies (CNES).
The spacecraft will fly in the same orbit as its predecessors to ensure an uninterrupted line of sea level readings. This consistency is critical to predicting future sea level rise – and preparing for its consequences, Willis said.
Unlike previous missions, which involved only a single spacecraft, it will employ two satellites, each with a five-year primary mission, said Parag Vaze, Jason's JPL project manager. The first is scheduled to launch from Vandenberg Air Force Base in California in November, and the second will follow in 2025, making it the longest of Jason's missions to date.
Sentinel-6 / Jason-CS will also have a different ending than its ancestors, Vaze said.
In an effort to reduce the accumulation of space debris, the two satellites will be the first in the Jason line to perform a planned orbit once they complete their final tasks. Even as older satellites continue to circle the globe, their younger siblings will burn into the atmosphere as they return to Earth.