“Less than a month after it was put in orbit, the ocean-mapper Jason-2 has returned its first pictures to Earth.
From an altitude of more than 1,300km, the spacecraft is now feeding back data covering nearly the entire globe.
Jason-2 is set to become the primary means of measuring the shape of the world’s oceans, taking readings with an accuracy of better than 4cm.
The information will be crucial to our understanding of both sea level rise and changing ocean currents.
Its key instrument is the Poseidon 3 solid-state altimeter. It constantly bounces microwave pulses off the sea surface.
By timing how long the signal takes to make the return trip, it can determine sea surface height. Additionally, the signal can indicate the height of waves and wind speed.
Elevation is a critical parameter for oceanographers. Just as surface air pressure reveals what the atmosphere is doing above, so ocean height will betray details about the behaviour of water down below.
Jason data gives clues to temperature and salinity. When combined with gravity information, it will also indicate current direction and speed.
The Jason lineage shows that mean sea level has been rising by about 3mm a year since 1993.”
Its cool how you can see a build up of seawater on the western side of the Pacific Ocean. Bonus points for those who can tell us why! (Think waaaaay back to your physical oceanography class if you took one)