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.

The Importance of Sea Oats

Wherever possible, the City of Cape Canaveral utilizes green infrastructure to increase its resilience against climate hazards such as coastal flooding and sea level rise. Being a barrier island municipality, the City regularly contends with powerful tropical cyclones and king tides. The City’s beach and its vegetated dune system are the first line of defense when it comes to mitigating the impacts of these hazards.

In order to maintain and continually strengthen its dune system, the City hosts an annual sea oats planting event. Sea oats are a perennial grass native to the US southeast, being found anywhere from Texas to Virginia. As they grow, the roots of the plants will burrow down several feet and form complex webs, which act to stabilize sand dunes and hold them in place. Above ground, the sea oats long wispy reeds serve to catch wind blow sand, often leading to a buildup of material at the base of the plants. Over time this build up will cause the sand dunes to increase in height. This height buildup adds to the overall resilience of the beach by allowing it to be able to stop higher tides and storm surges from overtopping the dunes.

In January 2021 the City held its largest planting event ever, managing to plant 20,000 sea oats across nearly 2 miles of beach with the help of roughly 400 dedicated volunteers. This green infrastructure initiative is arguably one of the City’s greatest environmental outreach programs, routinely attracting dozens of eager volunteers. Years of education and excellent program results (i.e. one of the best vegetative dune systems in Brevard County) have reinforced the success of this program.

In 2019 the City of Cape Canaveral’s released Vulnerability Assessment, completed after months of analysis and outreach by City Staff and the East Central Florida Regional Planning Council (ECFRPC), highlighting the threat of rising sea levels and coastal storms in our area. Funded by a grant from the Florida Department of Environmental Protection (FDEP) through their Florida Resilient Coastlines Program (FRCP) — a NOAA approved program — the report created by the ECFRPC examines the impacts of sea level rise and flooding specifically within Cape Canaveral. The report employs several models developed by the US Army Corps of Engineers (USACE) and NOAA to project possible sea level rise scenarios and the respective socio-economic impacts on the City. Timeframes evaluated as part of the report include 2040, 2070 and 2100.

According to the report’s findings the City can expect and should accordingly plan for 5.15 to 8.48 feet of sea level rise by 2100 with the ever possibility of increasing beach erosion and hurricane activity. In light of these issues, the planting of sea oats is one of the easiest and most economically feasible coastal protection projects presently available. Therefore, the City intends to keep this annual tradition in order to increase beach habitat, coastal resiliency and overall sustainability.

While the phenomenon of sea level rise does not affect the number or intensity of tropical cyclones, it can exacerbate their overall impacts on a shoreline. These impacts are primarily manifested in the form of higher storm surge values. Let's explore further and in doing so utilize a recent real-world case study for reference.

According to the National Oceanic and Atmospheric Administration (NOAA), global sea levels have risen on average 8–9 inches (21–24 centimeters) since 1880. Storm surge itself is defined as an abnormal rise in seawater level during a storm, measured as the height of the water above the normal predicted astronomical tide. The surge is caused primarily by a storm’s winds pushing water onshore. Sea level rise - which is currently being caused by melting glaciers and the thermal expansion of sea water - allows for higher storm surge potential by simply increasing the average height of the ocean, making more water available to push inland. As a result even weaker hurricanes can now bring a higher storm surge to coastal communities, which is important to remember when preparing for the annual hurricane season. Storm surge is statistically one of the most dangerous elements of a hurricane, not wind as many may think.

An example of this in practice can be seen during the landfall of 2017’s Hurricane Irma along the southwest coast of Florida. Hurricane Irma was a powerful long-track Cape Verde storm that caused extensive damage across its path as it moved through the Atlantic between August 30 (the date of its formation) to September 14, 2017 (the date of its dissipation). Irma became the first category 5 hurricane to strike the Leeward Islands on record. It was also considered at the time to be the most powerful hurricane on record in the open Atlantic, outside of the Caribbean Sea and Gulf of Mexico until it was surpassed by Hurricane Dorian in 2019.

Irma struck the Florida Keys as a category 4 storm, then moved northward making a second landfall along the southwest coast of Florida. It eventually moved up the spine of the Florida Peninsula and brought significant wind and storm surge related damage with it. First Street Foundation, an American nonprofit specializing in flood risk research and technology, conducted a 2018 analysis of Irma’s storm surge across Florida in collaboration with Columbia University professor Dr. Jeremy Porter, and found that due to the amount of sea level rise since 1970, an additional 57,000 homes were impacted by storm surge that otherwise wouldn’t have been.

Sea levels off the coast of Florida specifically have risen on average 7 inches since 1970 according to regional tidal data. Researchers used a geospatial analysis to model the impact of an Irma-like storm at the sea levels seen in 1970, and found that about 57,000 of the properties impacted would not have been affected with 1970 sea levels. According to analysis, sea level rise has a non-linear positive impact on storm surge, with the current observed sea level rise resulting in an additional 23% relative increase in storm surge. To see the researchers full methodology please visit the web address below.

Hurricane Irma: The Contribution of Sea Level Rise to Storm Surge and Damage

This important research tells us that coastal residents should review their preparedness plans and their current flood risk. Properties that may not have been at risk to surge previously could now be more vulnerable.

NASA’s Newest Disaster Monitoring Satellite: NISAR

The National Aeronautics and Space Administration, or NASA as it is more commonly known, is actually responsible for numerous other scientific endeavors besides space exploration. NASA also has a heavy involvement in the study and monitoring of our own home planet: Earth. Each year, NASA scientists cross the land, take to the seas and fly in the skies to better understand our changing world. Supporting these field studies from high above are dozens of space-based instruments affixed to satellites that help contribute invaluable data towards showcasing the inner workings of nature. And next year, to further this mission of observation, NASA will launch a new state-of-the-art disaster monitoring satellite called NISAR that will be unlike any other before it.

NISAR’s primary mission will be to act as an early warning system for potential natural disasters, as well as to help track the melt rate of ice sheets that are contributing to sea level rise. The satellite will be so sensitive that it will even be able to track shifts in the distribution of vegetation worldwide to monitor deforestation and crop yields. To do this, the spacecraft will utilize two kinds of synthetic aperture radar (SAR) to measure changes in Earth’s surface. The satellite will use a wire mesh radar reflector antenna nearly 40 feet in diameter at the end of a 30-foot-long boom to send and receive signals to and from Earth’s surface. With these systems, NISAR will be able to detect movements of the planet’s surface as small as 0.4 inches across an area similar in size to half a tennis court. It will scan the Earth’s entire surface every 12 days over the course of its three-year mission scanning seas, land and ice sheets alike. 

Movement of the Earth’s surface can tell researchers a lot. For example, ground movement can indicate how much water is inside an aquifer, or how much magma is moving underneath an active volcano. It could also show how much ice is melting at the poles, and in turn how much the melt is contributing to sea level rise. 

To learn more about the NISAR mission visit: https://nisar.jpl.nasa.gov/