Europe’s space agency has unveiled the first images from a European satellite sent into space to measure moisture and salinity back on Earth.
The Soil Moisture and Ocean Salinity (SMOS) mission has been doing exactly what its name implies since it was launched last year. Now the European Space Agency has released the first images created with data from the satellite. By learning more about water on the planet researchers hope to improve climate models, as well as their ability to predict floods and droughts.
SMOS measures the radiation emitted from Earth known as ‘brightness temperature’ and this is converted into soil and salinity readings. As Nature’s Katharine Sanderson noted in her story about the launch of the satellite:
SMOS is fitted with an instrument called MIRAS (Microwave Imaging Radiometer using Aperture Synthesis), which will measure the volume of microwaves coming from Earth at roughly 1.4 gigahertz, in the frequency band known as the L-band.
“At this frequency the signal is very sensitive to the moisture,” says Kerr. Dry soil emits much more electromagnetic radiation at this frequency than does wet soil, and so appears brighter — in the same way that hotter objects look brighter when viewed by a thermal-imaging camera, he explains.
 
These images show the calibration necessary on measurements from SMOS. Factors such as temperature variations on receivers and light reflecting off the Moon can cause errors, notes ESA. The left image shows uncalibrated brightness temperature over Australia, the right image is the calibrated data.
“Our development team is extremely happy and proud to see the real performance of the SMOS system in orbit,” says Achim Hahne, the European Space Agency’s SMOS project manager (press release). “We are only half-way through the in-orbit commissioning phase and it is rewarding to see these first very promising calibrated products delivered by SMOS.”
Images: ESA