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News  First images from ESA’s water mission
In less than four months since launch, the first calibrated images are being delivered by ESA’s SMOS mission. These images of 'brightness temperature' translate into clear information on global variations of soil moisture and ocean salinity to advance our understanding of the water cycle. Launched on 2 November, the Soil Moisture and Ocean Salinity (SMOS) mission is improving our understanding of Earth’s water cycle by making global observations of soil moisture over land and salinity over oceans. By consistently mapping these two variables, SMOS will not only advance our understanding of the exchange processes between Earth’s surface and atmosphere, but will also help to improve weather and climate models.
In addition, the data from SMOS will have several other applications in areas such as agriculture and water resource management.
Since it was launched, engineers and scientists from various institutes in Europe have been busy commissioning the SMOS satellite and instrument. This commissioning phase, which will continue until the end of April, initially involved testing the Proteus platform – a generic 'satellite bus' developed by the French space agency CNES and Thales Alenia Space – and the all-important MIRAS instrument developed by EADS-CASA in Spain under contract to ESA. Both platform and instrument have shown excellent performance during their first four months in orbit.
Achim Hahne, ESA's SMOS Project Manager, said, "Our development team is extremely happy and proud to see the real performance of the SMOS system in orbit. 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."
MIRAS produces a snapshot of brightness temperature every 1.2 seconds. The image of Scandinavia, at the top, is an example of one snapshot acquired by SMOS. From these images of brightness temperature, it is possible to derive how much moisture there is in the surface layers of soil and how much salt there is in the surface waters of the oceans. High brightness temperatures translate into dry soils and low brightness temperatures into wet areas. This is why bodies of water show up as cold spots.
Calibration and validation are a major undertaking in any Earth observation mission. Once the data get to the ground, they need to be checked that they make sense and can be used for scientific research. The last three months have been dedicated to performing these calibration activities in order to assess the performance of the mission.
The image showing Brazil highlights the rainforest, which is relatively stable and bright, and the Amazon River is seen in lower brightness temperatures.
Yann Kerr, who first proposed the mission to ESA, added, "SMOS has delivered its first products earlier than expected and of a quality better than the specifications." The acquisition of these calibrated images marks a very important step in the progress of the SMOS mission and also demonstrates the excellent quality and availability of the data, which will soon be available to the science community.
Jordi Font, the mission’s Lead Investigator for ocean salinity, said, "For the ocean products, a lot of work still has to be done before the release of operational data. The low sensitivity to variations in salinity requires very accurate instrument calibration and data processing to achieve the mission’s measurement goals for ocean salinity. However, the excellent performance of MIRAS, and the work being done in commissioning means we are very close to obtaining good results for measuring salinity."
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Earth Explorers (http://www.youtube.com/watch?v=r_-HsOmSiSc &feature=PlayList &p=A86C2C24C4DF8BB7 &index=13)