. Earth Science News .
WATER WORLD
Keeping a Steady Eye on Sea Level Change From Space
by Staff Writers
Pasadena CA (JPL) Jul 13, 2020

This chart shows the rise in global average sea level from January 1993 to January 2020. The measurement is made using data collected by the Sentinel-6/Jason-CS mission's predecessors, the TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 satellite missions. Image Credit: NASA Goddard Space Flight Center

Over the course of nearly three decades, an uninterrupted series of satellites has circled our planet, diligently measuring sea levels. The continuous record of ocean height that they've built has helped researchers reveal the inner workings of weather phenomena like El Nino and to forecast how much the ocean could encroach on coastlines around the world. Now, engineers and scientists are preparing two identical satellites to add to this legacy, extending the dataset another decade.

Both spacecraft are a part of the Sentinel-6/Jason-CS (Continuity of Service) mission, a U.S.-European collaboration that aims to make some of the most accurate measurements of sea levels around the world. The first satellite to launch, Sentinel-6 Michael Freilich, will lift off in November. Its twin, Sentinel-6B, will launch in 2025. Both will assess sea levels by sending electromagnetic signals down to the ocean and measuring how long it takes for them to return to the spacecraft.

"This mission will continue the invaluable work of accurately measuring sea surface height," said Karen St. Germain, director of NASA's Earth Science Division. "These measurements enable us to understand and predict sea level changes that will affect people living in coastal regions around the world."

The satellite will build on efforts that began in 1992 with the launch of the TOPEX/Poseidon mission and that continued with three more missions over the years: Jason-1, OSTM/Jason-2, and Jason-3. Sentinel-6/Jason-CS aims to extend the nearly 30-year sea level dataset that these previous missions built by another 10 years.

Measuring the height of the ocean gives scientists a real-time indication of how Earth's climate is changing, said Josh Willis, the mission's project scientist at NASA's Jet Propulsion Laboratory in Southern California. The oceans absorb about 90% of the excess heat from the planet's warming climate. Seawater expands as it heats up, resulting in about a third of the modern-day global average sea level rise. Melting ice from land-based sources like glaciers and ice sheets accounts for the rest.

To understand how rising seas will affect humanity, researchers need to know how fast this is happening, said Willis. "Satellites are the most important tool to tell us this rate," he explained. "They're kind of a bellwether for this creeping global warming impact that's going to inundate coastlines around the world and affect hundreds of millions of people."

Currently, sea levels rise an average of 0.13 inches (3.3 millimeters) per year, more than twice the rate at the start of the 20th century. "By 2050, we'll have a different coastline than we do today," said Willis.

"As more and more people move to coastal regions, and coastal megacities continue to develop, the impact of sea level change will be more profound on those societies," said Craig Donlon, mission project scientist at the European Space Agency.

Setting the Standard
The information that Sentinel-6 Michael Freilich gathers will join a dataset that's become the gold standard for climate studies from space. This is because the chain of overlapping satellites that started with TOPEX/Poseidon has continuously measured ocean heights since the early 1990s. That continuity is key to this dataset's success.

Some of the long-term datasets climate scientists rely on, like ocean temperature or the height of tides, have gaps or major changes in how data was collected (like before and after satellite records began) that make understanding the long-term climate signal challenging. Researchers must account for these variations to ensure that their results are truly representative of the phenomena they're looking at.

The satellites that followed TOPEX/Poseidon - Jason-1, OSTM/Jason-2, and Jason-3 - flew in the same orbit as one another, each launching before the older one was decommissioned. When Sentinel-6 Michael Freilich lifts off later this year, it will orbit Earth 30 seconds behind the Jason-3 satellite, which launched in 2016.

Scientists will then spend a year cross-calibrating the data collected by the two satellites to ensure the continuity of measurements from one mission to the next. Engineers and scientists will do the same cross-calibration with Sentinel-6 Michael Freilich's twin in five years as its predecessor's mission winds down.

Without these satellites and the data they've collected, researchers would have a much rougher understanding of the rate of sea level rise, as well as of phenomena like El Nino. This is a weather pattern triggered by a huge shift in the winds that normally blow from east to west across the equatorial Pacific Ocean.

An El Nino can shift ocean currents and global weather patterns, bringing torrential rain to the Southwestern U.S. and triggering droughts in Asia and Australia. Its counterpart, La Nina, can have the opposite effect.

One of the discoveries to come out of this sea level dataset is the far-reaching effects that El Nino and La Nina can have on the world.

"In 2010, there was a massive La Nina and it essentially flooded huge parts of Australia and Southeast Asia. It rained so much on land, it dropped global sea levels by one centimeter [0.4 inches]," said Willis. "We had no idea it could have such a massive impact on global sea level."

The global view that the Sentinel-6 Michael Freilich satellite will provide, together with sea level data from models and observing stations, will provide invaluable information for governments and local authorities tasked with planning for things like sea level rise and storms, said Donlon.


Related Links
Sealevel Science at JPL
Water News - Science, Technology and Politics


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


WATER WORLD
To curb climate change, scientists call for robust seagrass preservation efforts
Washington DC (UPI) Jul 07, 2020
It's not just corals that are suffering as the world's oceans are reshaped by climate change and other harmful human activities - a study published Tuesday in the journal Global Change Biology shows marine seagrass meadows are also in decline. According to a recent survey of marine carbon stocks in Western Australia's Cockburn Sound, the region lost nearly nine square miles of seagrass between the 1960s and 1990s as a result of nutrient runoff caused by coastal development. Seagrass mea ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

WATER WORLD
Myanmar army sacks officers over landslide tragedy

Iran reports 'accident' at nuclear site, warns enemies

Iran says damage at nuclear site 'significant'

More than 160 dead in Myanmar jade mine landslide

WATER WORLD
Geologists identify deep-earth structures that may signal hidden metal lodes

Europe radioactivity likely linked to nuclear reactor: UN watchdog

Deutsche Bank teams up with Google in cloud services

The lightest shielding material in the world

WATER WORLD
Ancient Polynesians, Native Americans made contact before Europeans arrived

New technology combines wood, bacteria, sunlight to purify water

Climate change to fuel extreme waves in Arctic

To curb climate change, scientists call for robust seagrass preservation efforts

WATER WORLD
First comprehensive documentation of glacial retreat in the Alps

Giant A-68 iceberg three years on

Pink ice in Italy's Alps sparks algae probe

Arctic plants may not provide predicted carbon sequestration potential

WATER WORLD
Overharvesting threatens 'Himalayan Viagra' fungus: IUCN

China aims to phase out sale of live poultry at food markets

Nepal offers locust bounty as swarms threaten crops

Antibiotic use on crops isn't being monitored in most countries

WATER WORLD
Japan rescuers battle to reach thousands trapped by floods

Conditions ripe for active Atlantic hurricane season, Amazon fires

Rain pounds central Japan, 55 feared dead in south

50 dead in Japan floods as rescuers 'race against time'

WATER WORLD
DR Congo troops kill Angolan soldier in border incident

South Africa deploys military medics to virus hotspot

Nine Mali soldiers killed in ambush: army

Senegal capital fights shoreline developers

WATER WORLD
Racism in the UK: the effects of a 'hostile environment'

Early peoples in Pacific Northwest were smoking smooth sumac

In the wild, chimpanzees are more motivated to cooperate than bonobos

Archaeologists find ancient circle of deep shafts near Stonehenge









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.