ESA’s SMOS satellite: Five Years of Soil Moisture and Sea Salinity Measurements

ESA’s SMOS satellite has clocked up more than one billion kilometres orbiting Earth to improve our understanding of our planet’s water cycle.

Marking its fifth birthday, all the data collected over land and ocean have been drawn together to show how moisture in the soil and salinity in the ocean change over the year.

The Earth Explorer SMOS satellite mission was launched on 2 November 2009 from Plesetsk in Russia.

Carrying a novel sensor, it captures images of ‘brightness temperature’.

These images correspond to microwave radiation emitted from Earth’s surface and can be related to soil moisture and ocean salinity, two key variables in Earth’s water cycle.

The animation above uses five years of SMOS data to show how, on average, moisture in the soil changes with the seasons around the world.

It illustrates how change is more pronounced at higher latitudes, but monsoon dynamics in the Indian subcontinent are also clearly visible.

The ‘Sahel transition’ region in Africa is well depicted and seasonal flooding in regions such as La Plata in Argentina and the Orinoco Basin in Veneuzela can also be seen.


Over oceans, measurements from SMOS, the longest continuous record from space, show monthly differences in sea-surface salinity with respect to the average salinity, and show large deviations in the tropical Pacific Ocean and in the Indian Ocean.

This is linked to the occurrence of La Niña, which is associated with cooler than normal sea-surface temperatures in the eastern Pacific, and the Indian Ocean Dipole, which describes sea-surface temperature differences between the eastern and western equatorial Indian Ocean.

While these results are of interest to understanding aspects of the water cycle, information from SMOS is being used for a number of practical applications.

In fact, 18 TB of SMOS data are distributed every year, of which around 13 TB are used by scientists and around 5 TB for near-realtime applications by operational users.

For example, integrating these accurate near-realtime observations into the European Centre for Medium-Range Weather Forecasts’ (ECMWF) system is helping to improve air temperature and humidity forecasts near the surface. In addition, the inclusion of SMOS observations are helping to improve the prediction of rain.

NASA AMS-2 Particle Detector on ISS Finds Dark matter in Cosmic Rays - Update

The Alpha Magnetic Spectrometer attached to the International Space Station.

Credit: NASA

New research published Thursday in the journal Physical Review Letters shows researchers are making important progress in the hunt for dark matter, using the Alpha Magnetic Spectrometer (AMS), a state-of-the-art cosmic ray particle physics detector located on the exterior of the International Space Station.

The results include new detections of anti-matter particles that could provide new clues in the search for dark matter, invisible matter that can't be directly detected but can be inferred. An overview of the latest findings can be found here.

Computer-generated drawing of the Alpha 
Magnetic Spectrometer (AMS). Credit: NASA

The MIT group leads an international collaboration of scientists that analyzed two and a half years' worth of data taken by the Alpha Magnetic Spectrometer (AMS), a large particle detector mounted on the exterior of the International Space Station, that captures incoming cosmic rays from all over the galaxy.

Among 41 billion cosmic ray events, instances of cosmic particles entering the detector, the researchers identified 10 million electrons and positrons, stable antiparticles of electrons.

Positrons can exist in relatively small numbers within the cosmic ray flux.

An excess of these particles has been observed by previous experiments, suggesting that they may not originate from cosmic rays, but come instead from a new source.

In 2013, the AMS collaboration, for the first time, accurately measured the onset of this excess.

The new AMS results may ultimately help scientists narrow in on the origin and features of dark matter, whose collisions may give rise to positrons.

"The AMS results announced today are tremendously provocative, and will drive scientists around the world to continue pursuing one of the biggest mysteries in the cosmos: dark matter," NASA chief scientist Ellen Stofan said at the agency’s headquarters in Washington.

"The clear and definitive data from AMS represent the caliber of scientific discovery enabled by our unique laboratory in space, the International Space Station."

"Today we are one step closer to answering the fundamental questions about how our universe works, and we look forward to many more exciting twists in this developing story."

AMS was constructed, tested and operated by an international team of 56 institutes from 16 countries and organized under the sponsorship of the U.S. Department of Energy's Office of Science.

NASA's Johnson Space Center in Houston manages the AMS Integration Project Office. AMS was launched on space shuttle Endeavour on May 16, 2011.

Operations on the space station began three days later. AMS continues operations aboard the station today.

More Information
"Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station" Phys. Rev. Lett. 113, 121102 – Published 18 September 2014 - 10.1103/PhysRevLett.113.121102

ESA GOCE: Lifetime of gravity measurements heralds new beginning

ESA's GOCE mission has delivered the most accurate model of the 'geoid' ever produced, which will be used to further our understanding of how Earth works. 

The colours in the image represent deviations in height (-100 m to +100 m) from an ideal geoid. 

The blue shades represent low values and the reds/yellows represent high values. 

A precise model of Earth's geoid is crucial for deriving accurate measurements of ocean circulation, sea-level change and terrestrial ice dynamics. 

The geoid is also used as a reference surface from which to map the topographical features on the planet. 

In addition, a better understanding of variations in the gravity field will lead to a deeper understanding of Earth's interior, such as the physics and dynamics associated with volcanic activity and earthquakes. 

Image courtesy ESA/HPF/DLR.

Although ESA's GOCE satellite is no more, all of the measurements it gathered during its life skirting the fringes our atmosphere, including the very last as it drifted slowly back to Earth, have been drawn together to offer new opportunities for science.

Carrying the first 3D gravity sensor in space, this state-of-the-art satellite measured Earth's gravity with unprecedented accuracy.

GOCE's four years in orbit resulted in a series of four gravity models, each more accurate than the last.

These models have been used to generate corresponding 'geoids' - the surface of a global ocean moulded by gravity alone.

Shaped by differences in gravity, the geoid is a crucial reference for understanding ocean circulation, sea-level change and ice dynamics.

From a mission that just keeps giving, a fifth model has now been produced. It incorporates data collected throughout the satellite's 42-month operational life.

The previous geoid, released in March 2013, was based on 27 months of measurements.

The satellite was designed to orbit at an extremely low altitude of 255 km to gain the best possible gravity measurements.

At the end of 2012, low fuel consumption allowed operators to extend its life and start to lower the satellite a further 31 km for even more accurate measurements.

This was at the very limit of its capability but maximised the return for science.

After more than doubling its planned life in orbit, the satellite ran out of fuel and drifted back into the atmosphere in November 2013.

The fifth gravity model and geoid, which ESA has recently made available, includes these final precious measurements, right up until the satellite finally stopped working and ironically succumbed to the force it was designed to measure.

Although the satellite is no longer in orbit, scientists now have the best possible information to hand about Earth's gravity, effectively a new beginning for the mission.

GOCE has already shed new light on different aspects of Earth and surpassed its original scope in a number of ways.

It is being used to understand how oceans carry huge quantities of heat around the planet and to develop a global height reference system.

It has provided information about atmospheric density and winds, mapped the boundary between Earth's crust and upper mantle, and used to understand what is going on in these layers far below our feet.

GOCE's achievements also include mapping a scar in Earth's gravity caused by the 2011 Japanese earthquake.

Changes in Earth’s gravity field resulting from the earthquake that hit Japan on 11 March 2011 (mE=10-12s-2). 

A combination of data from ESA’s GOCE mission and the NASA–German Grace satellite, shows the ‘vertical gravity gradient change’. The 'beachball' marks the epicentre.

Credit: ESA

The ultimate geoid model and gravity data will be used for years to come for a deeper understanding of Earth.

ESA's GOCE Mission Manager, Rune Floberghagen, said, "We are very happy with the results of the final, super-low altitude phase of our mission.

"In fact, efforts made by the mission team and by scientists to secure flight operations at these extreme altitudes and to process the data have resulted in a doubling of the information content and a very significant increase in spatial resolution.

"Indeed, our new 'Release 5 solutions' go well beyond the ambitious objectives we had when the GOCE project started.

"Scientists worldwide now have a satellite-based gravity field model at hand that will remain the de facto standard for many years to come."