NASA Launches Sentinel-6 Michael Freilich Spacecraft 

The world's latest ocean-monitoring satellite launched successfully on Saturday, November 21 from Vandenberg Air Force Base in California via a SpaceX Falcon 9 rocket. Called the Sentinel-6 Michael Freilich spacecraft, its primary mission is to monitor global sea level rise with extreme precision. It also includes instrumentation to help improve weather forecasts, track hurricanes, and enhance climate models. In orbit the Sentinel-6 satellite - a partnership between NASA and the European Space Agency (ESA) - will collect sea level measurements down to the centimeter for 90% of the world’s oceans. 

Besides the oceans, the satellite will also study Earth’s atmosphere with what’s called the Global Navigation Satellite System — Radio Occultation (GNSS-RO) to collect highly accurate global temperature and humidity information. Developed by NASA’s Jet Propulsion Laboratory, the GNSS-RO instrument tracks radio signals from other navigation satellites to measure the physical properties of Earth’s atmosphere. As a radio signal passes through the atmosphere, it slows, its frequency changes, and its path bends. Called refraction, this effect can be used by scientists to measure minute changes in atmospheric physical properties, such as density, temperature, and moisture.

The precise global atmospheric measurements made by the Sentinel-6 Michael Freilich spacecraft will complement atmospheric observations by other GNSS-RO instruments already on other satellites in space. Specifically, the National Oceanic and Atmospheric Administration’s National Weather Service meteorologists will use insights from Sentinel 6’s GNSS-RO to improve weather forecasts. Also, the GNSS-RO information will provide long-term data that can be used both to monitor how our atmosphere is changing and to refine models used for making projections of our changing climate. Data from this mission will help track the formation of hurricanes and support models to predict the direction storms may travel. The more data gathered about hurricane formation (and where a storm might make landfall), the better in terms of helping local efforts to mitigate damage and support evacuation plans. Sea level rise data will also help better determine which areas may see more frequent flooding, allowing for mitigation efforts to be streamlined and targeted at the most vulnerable areas by federal, state, and local governments such as the City of Cape Canaveral.  

For more info about the spacecraft and sea level rise click the NASA link below: 

https://www.nasa.gov/feature/esnt/2020/beating-back-the-tides 

Using Gravity to Measure Sea Level Rise

Sea levels around the world are rising, creating numerous issues for coastal communities like Cape Canaveral that can range from high tide flooding to stormwater backups. It is well known by scientists that much of the reason for Earth’s rising oceans is due to the melting of polar ice sheets and glaciers. However, many are still trying to understand which ice sheets and glaciers are contributing the most meltwater. One of the many tools scientists use to answer these questions is gravity.

Gravity is our constant companion. Its pull is ever present, invisibly shaping our world. Walking, construction, flight, and even how plants grow are all dictated by the tug of gravity. What is gravity exactly? Gravity is the force by which a planet or other body draws objects toward its center. Anything that has mass also has gravity. The more mass an object has the more of a gravitational pull it will exert. But believe it or not this pull is actually not uniform across the Earth, with some areas having more gravitational pull than others based on geographic characteristics. For example, a mountain range will have more gravity than say open plains because the mountain range literally has more material and therefore more mass. Scientific agencies like NASA have even mapped differences in regional gravitational pull.

While these differences in gravitational pull are imperceptible to people, they do exist, and it is these differences that allow scientists to see what is causing modern sea level rise. Currently orbiting the Earth are two identical satellites belonging to a mission called GRACE-FO, or the Gravity Recovery and Climate Experiment Follow On. Launched by NASA in conjunction with the German Research Center for Geosciences in 2018 from Vandenberg Air Force Base, California, GRACE-FO is a followup mission to the nearly identical twin GRACE satellites which operated from 2002 to 2017. Like its predecessor mission, GRACE-FO directly measures the mass loss of glaciers and ice sheets via a process called gravimetry where scientists essentially “weigh” Earth’s ice by measuring its gravitational pull on the mission’s twin satellites.

As the planet warms, polar ice sheets and glaciers melt. As they melt they lose mass and therefore their gravitational pull decreases. As the twin satellites fly overhead at the same altitude in orbit with one trailing the other by about 140 miles (220 kilometers), changes in mass (and gravity) below will ever so slightly pull the spacecraft together or apart. The satellites transmit their distance from each other to scientists on Earth, which allows them to get a fix on how much mass is being lost across the poles and where. The two satellites orbit each pole about 15 times a day. 

So, what has the GRACE mission discovered? Results from the first two GRACE satellites have shown that between 2002 and 2016, Greenland’s ice sheet shed about 280 gigatons (280 billion tons) of ice per year, causing global sea levels to rise by about half an inch, or roughly 0.03 inches per year. This melting is unfortunately accelerating. In 2019 over the course of just one summer, the GRACE-FO mission recorded a loss of 600 gigatons of ice, which is more than double the average annual losses observed between 2002 and 2016.

Melting ice in Antarctica is also contributing to sea level rise. Between 2002 and 2017, scientists found that mass losses from the Greenland and Antarctic ice sheets combined to contribute about 0.04 inches per year to global mean sea level. That’s about one third of the total rise in sea level over that time.

Additionally, GRACE-FO monitors mass loss from mountain glaciers outside the polar regions, including Alaska, Canada, the Andes in South America and Europe. According to the mission’s findings, mountain glaciers outside the poles lost about 200 gigatons of ice per year between 2002 and 2016. This loss contributed to 0.31 inches of global mean sea level rise.

This ongoing stream of real world scientific data will prove invaluable to policymakers, elected officials, emergency management offices, and government staffers both in the state of Florida and around the country; especially in coastal communities like Cape Canaveral. Local and state vulnerability assessments (like the City’s 2019 Vulnerability Assessment) incorporate forecast models that utilize data from satellites such as those serving in the GRACE-FO mission to make more accurate sea level rise predictions. Such predictions can better inform the public about where and when sea level rise will be most impactful; allowing for more efficient planning of mitigation efforts.

For more information about the GRACE-FO mission please use the link below.

Want even more info on sea level rise? Find more insightful and up-to-date stories about our planet’s changing coastlines in NASA’s Earth Observatory’s sea level rise collection. Explore other stories about sea level rise by NASA scientists in Rising Waters.

Space Coast Transportation Planning Organization Vulnerability Assessment

In July 2017, in partnership with the East Central Florida Regional Planning Council (ECFRPC), the Space Coast Transportation Planning Organization (SCTPO) began a Sea Level Rise Vulnerability Assessment for Brevard County. The assessment utilized the Sea Level Scenario Sketch Planning Tool, created by the University of Florida GeoPlan Center and the Florida Department of Transportation (FDOT), to assess transportation features and public service facilities for sea level rise inundation on three levels of projections and the years 2040, 2070, and 2100. The completed findings were presented to the SCTPO Governing Board in February 2018.

Since Brevard County is a coastal community, not only is coastal resiliency a growing concern, but the Fixing America’s Surface Transportation Act or FAST Act also requires transportation planning organizations to account for resiliency during their planning efforts. As solutions, planning, and implementation take time, the Sea Level Rise Vulnerability Assessment serves as a first step for the SCTPO, Brevard municipalities, and multi-modal agencies, in highlighting this environmental factor.

See the final report here: Space Coast TPO Sea Level Rise Analysis

The City of Cape Canaveral undertook a similar vulnerability assessment with the ECFRPC, which was completed in 2019. The SCTPO is now developing a resiliency action plan that incorporates the findings and recommendations set forth by the agency’s vulnerability assessment and turns them into actionable policy and infrastructure directives.