Charting sea level from space

eleven ten nine stars of ignition sequence look down on that fragile bubble of life it is often said that the first color images of the earth from

space

inspired the ecological movement five decades later satellite images of our planet have become essential to our survival satellites in

space

give us different lenses different ways to look at our planet earth if you look in the visible you can see the clouds and you can see the towns and cities during the day if you look in the thermal infrared you can observe the temperature patterns of the sea ​​surface as the ocean is moving, if you look at the radar, then you can see the surface roughness characteristics that give us wave access to many different things, including how crops develop during the growing season and whether You put all this together, then you start.

To get a general idea of ​​how our planet works, this is useful for governments, local authorities, farmers and even people like you and me, because all our data is fed into the weather forecast and we use it every day to decide whether to use altimetry. It's a very special set of measurements that gives us access to sea

level

and we can monitor sea

level

rise, but it also gives us access to how ocean circulation works because there are hills and bulges on the sea surface that correspond to the ocean circulation, so By understanding planet Earth through measurements, we can today provide evidence of change with the European Copernicus program.

We have a fleet of operational spacecraft that provide those different colors of our planet Earth. This satellite scans the planet's surface to provide precise information. for changes in sea level, but to achieve such precision, its instruments must be constantly calibrated from fixed points on the earth's surface, for this it was necessary to develop new techniques. This challenge was accepted by an engineering professor working on the Greek island of Crete. It is an ideal place because we see different satellites crossing each other at the same point, that was the impetus behind the beginning of this project, working together with the European space agency, Professor Martikas and his team developed a unique system of interconnected devices for calibration of satellites in its center.

The feature is a prototype mechanism called a transponder. It is as if the transponder were another satellite on Earth. This growing network of devices has been used to calibrate satellites passing over Crete for the past decade, but now the system is being upgraded. We have a new satellite. sentinel 6 michael freilich and here we are implementing a synthetic aperture radar altimeter that is dedicated to making measurements of sea level rise. We've tested those techniques to get better resolution on the ground now to know how good our measurements are that we need to make. Ground measurements As the new satellite replaces its predecessor, long-time collaborators Stelios Martikas and Craig Donlin reunite on the southern coast of Crete, but their final destination is a small island on the very edge of Europe, legend has it that Gavdos was the home of the nymph Calypso who fell in love with Ulysses and kept him prisoner for seven years today with only a handful of permanent residents and little infrastructure the only way to reach Gavdos is by boat despite these difficulties however it was chosen as a site for a new improved version of the original transponder.

The location here is very strategic because the cables have three other satellites crossing that location and in ascending and descending orbits, so we can compare if the results are the same. Here it is. Wow Studios is fantastic. I can see many. changes here the new facility here has the ability to calibrate the antennas and make them exactly parallel so that they see the satellite at exactly the same point. We don't want any distance between transmission and reception, so the stereos, the satellite transmitter is a radar pulse that is received by this antenna exactly, it goes to the box where it is analyzed and amplified, yes, and then it is retransmitted back to the satellite here, yeah, the key here is that we know exactly how long it took from when it got to this antenna to when it arrived. has been transmitted back to the satellite and that time is nanoseconds, it is a big challenge because the satellite flies 13 30 kilometers 1330 kilometers in space, if we have only one measurement, we are never sure if it is the good measurement, so There are many people working on these aspects and we have worked hard to prepare for today.

It is the first day that we have a real measurement of the tandem mission of json3 and sentinel 6. Are you always worried about the sentinel 6 satellite michael freilix launched on November 21, 2020 from California to replace its predecessor json-3, but first the two satellites must fly together and jointly calibrate their instruments by sending a signal first to the transponder on the mountain and then nine seconds later to the new one in gavdos for the team on the ground, this is a decisive moment, okay, any time, yes , well done, fantastic, congratulations, congratulations, fantastic, everyone was very happy when the light came on and the buzzer went on, so at least you know we got the satellite this time.

Both Jason first and then Sentinel Six are very good news to get through and after all that hard work, thank you too for all your help and we look forward to working on the data later today. Whatever we produce has three objectives, one is to ensure the quality of The scientific measurements we produce give people the right information about climate change and help policy makers decide the right policy in terms of climate change. For every centimeter of sea level rise, we can expect a displacement of two to three million people. By the time we reach 2050, we can expect sea level rise of 20 to 30 centimeters globally; we may even have up to one meter or even two meters by 2100, that's flooding and that's lost land if we think about the approximately 600 million people. living in coastal regions around the world, these are huge numbers of people, their livelihoods, their communities, their cities, their very fabric of life is being torn apart because they have to relocate, so understanding the quality of measurement is extremely important.

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