Sea levels are rising, and the largest contribution to this phenomenon is the expansion of warming water. Melting glaciers account for the rest of the cause.
A new satellite has been launched from California, shaped like a dog kennel, which could be vital to understanding climate change. The unusual shape of the satellite, mostly because of the fixed solar panels on each side of the top, making a roof-life shape, keeps the satellite extremely stationary as it orbits. Sentinel-6 “Michael Freilich” has been sent with the overall goal of measuring the shape of the world’s oceans. The data will measure sea-level rise or fall and track how oceans may be moving around the globe.
The satellite project is a joint venture between Europe and the US that continue work completed by previous missions. Prior data revealed that over the past 28 years, sea levels have risen more than 3mm per year and is currently accelerating to 4mm per year.
Sentinel-6 will use a radar altimeter, an instrument that sends microwave pulses to the planet’s surface and then counts the time it takes to receive the return signal, which equates to elevation and width. The satellite is the most advanced of its kind, having the capability to track sea activities right up against coastlines and it can also monitor inland water behaviors.
Sea elevation is important to scientists because it is a vital indicator of what is happening below the surface. Elevation data gives clues about sea temperature as well as salinity, which when computed with the force of gravity can show direction and speed. One of the most important elements of the satellite’s data is the ability to predict future changes based on clear and accurate historical data.
Scientists point out that the 3mm per year figure is not uniform across the planet. Earth’s oceans store a vast amount of heat from the sun and how that energy is moved around the globe and interacts with the atmosphere drives our climate system. This makes sea level changes the most important factor in causing and predicting climate change patterns. Many factors come into play, the most impactful being large melting icebergs. For example, the Thwaites Glacier I Antarctica has the greatest effect of ocean height on the planet, and at very far distances.
Beyond oceanographers and climatologists, weather forecasters are interested in the data from Sentinel-6 as well. The return signal sent from the microwave signals can also measure the roughness of the sea, which helps to predict the strength of winds. Hurricanes gain their strength and behavior directly from the warm tropical waters, which are measured by the same altimeter instrument used in measuring sea expansion.
Other potential users of this information is ship routers who are trying to steer their vessels away from storms quickly. Ship routers need to see the eddies in the ocean, which indicate current streams and predict where the current will be the strongest. The altimeter from Sentinel-6 will provide accurate and quick information to make nautical decisions.
The information collected by Sentinel-6 can be used to predict El Nino events, which is fed by warm water shifts in the Pacific. We can begin to be proactive with coastal flooding plans by evaluating the bulges of the ocean as well, and where is safe to build nuclear power stations.
“Sentinel” is a name given to the satellite program from the European Union’s Copernicus Earth-observation program, the sixth in the series. “Micheal Freilich” was the former director of the US space agency Nasa’s Earth sciences division who died early 2020.
The major propulsion module that will keep the satellite in a very precise orbit to get the best sea level measurements was built by European scientists. Sentinel-6 has eight 5-newton thrusters to keep the 1.3 ton machine moving along its mission. The module is coined as a “plug-and-play” model that can be used to build other aircraft. This will allow scientists to have at their use a base so that building future spacecraft will be easier and faster.