Scientists find an explanation on how big storms behave in Saturn

Seva – Barcelona, June 24, 2013. A study led by Enrique Garcia Melendo, researcher of the Esteve Duran Observatory Foundation – Spaces Sciences Institute ICE (CSIC-IEEC), in collaboration with the Group for Planetary Sciences of the University of the Basque Country, and the European University Miguel Cervantes, has provided the key to understanding how giant storms develop on the surface of Saturn, according to a study carried out of the Great White Spot of the year 2010. The scientific results, which were obtained by analyzing the evolution of the Great White Spot generated in 2010, are published in the prestigious journal Nature Geosience.

Approximately once every Saturn year, equivalent to about 30 Earth years, a storm of huge proportions is generated on the surface of the planet that affects the appearance of its atmosphere on a global scale. These giant storms are called Great White Spots, because historically and since they began to be observed in 1876, they have appeared as very bright white regions, highly differentiated from the rest of the planet’s atmosphere through the observations with ground-based telescopes.

From the nineteenth century to the late twentieth century there have only been five major storms on Saturn. The sixth storm was predicted to occur in 2020, but anticipating itself 10 years, it appeared in 2010. In early December 2010, Saturn began to show a bright white cloud at mid-northern latitudes. It was the first sign of the generation of this majestic storm, which reached an area of ​​thousands of millions of square kilometers. This time, the Cassini spacecraft was able to obtain very high resolution images of the enormous structure. The storm originated at a point, the focus, but quickly stretched in length and produced a change in the atmosphere, creating a ring of white clouds that surrounded the planet in less than two months, perturbating the seemingly quiet vision we have of its clouds. The storm was so extraordinarily active that it produced an increase in the high stratosphere located above the storm of more the 60 degrees. Even more, the Cassini spacecraft, in orbit around Saturn, observed and monitro a record electrical activity during the storm’s duration, which lasted about seven months.

Both the analysis of the images of the storm sent by the Cassini probe, space mission of the european and american space agencies ESA and NASA, and the computer models of the storm and the further analysis of its clouds, have enabled this team of scientists to explain, for the first time, the storm’s behaviour.

The team of scientists who have published the results of this study in the journal Nature Geoscience, analyzed images taken by the Cassini spacecraft (NASA / ESA) to measure winds in the “head” of the storm, the focus where the activity originated, and found that in this region the storm interacted with the surrounding atmosphere forming very strong sustained winds up to 500 km per hour. “We did not expect such a violent circulation in the region of development of the storm, which was a symptom of a particular interaction between the storm and the planet’s atmosphere,” said Enrique Garcia, from the Esteve Duran Observatory Foundation.

Information of the mechanisms that cause other weather storms

The study published in Nature Geoscience accounts not only on the discovery of strong winds associated with the storm, but also reveals the mechanism that generates them. The team of scientists designed their own mathematical models, reproducing the storm on a computer and which give a physical explanation of the behavior of this giant storm on Saturn. Calculations showed that the focus of the storm, located in the lower layers of the atmosphere and unaccessible to observations from space, transported huge amounts of gas to the upper layers of the planet’s atmosphere where the clouds visible are located, and released huge amounts of energy that altered the appearance of the planet for months. This massive injection of energy interacted violently with Saturn’s prevailing winds to produce the observed winds of 500 km/h.

Despite the advances in the field obtaing through this study, the source that powers these giant storms is still a mystery. It is possible that it is located about 250 km below the cloud layers that are visible from space, where water condenses on Saturn. Despite its enormous activity, the storm can not substantially change the regime of prevailing winds, which blow constantly in the same direction as the parallels on Earth, but interact violently with them. An important part of the computer calculations were performed thanks to the Centre de Serveis Científics i Academics de Catalunya (CESCA), and computer resources of Sciences Institute de l’Espai (ICE).

Eventhough there is a tremendous curiosit to know about the physical processes that lead to the formation of these giant storms on Saturn, the study of these phenomena allows to gain insight into the weather patterns and behavior of the Earth’s atmosphere in an environment very different and impossible to simulate in a laboratory. Saturn’s storms are a test bed for studying the physical mechanisms that generate other meteorological phenomena on Earth.

Reference:
E. García-Melendo, R. Hueso, A. Sánchez-Lavega, J. Legarreta, T. del Río-Gaztelurrutia, S. Pérez-Hoyos, J. F. Sanz-Requena. Atmospheric Dynamics of Saturn’s 2010 giant storm. Nature Goescience, DOI:10.1038/ngeo1860.

Notes to the Editor
The Esteve Duran Observatory Foundation (FOED)
Private Astrophysical Research in Catalonia

The Esteve Duran Observatory Foundation (FOED) is a private non-profit organization created in 1997 to carry out cutting-edge research in Catalonia. The Foundation is named after Esteve Duran, creator of Esteve Duran Observatory. At the time of its creation, its 60cm aperture telescope was the largest astronomical observation instrument in Catalunya. The FOED, among other things, has made significant contributions to the knowledge of the solar system’s giant planets, Jupiter and Saturn, and has worked with the Space Telescope Science Institute on the discovery of planets around other stars.

Nature Geoscience is a magazine specialized in geosciences, ranging from ground geophysics to the other planets of the solar system. Founded in 2008 in the heart of Nature Publishing Group, it has quickly established itself as the journal with the highest impact in its field. This is the second time this team of scientists publishes an article in Nature on Saturn’s giant storm 2010, since the first studyappeared in an article in the July 2011 issue of Nature. The study was led by Agustín Sánchez Lavega Sciences, from the Planetary Science Group from the Basque Country University, which provided data on Saturn’s deep atmosphere by studying its development, being selecte for the cover of the magazine.

Links of Interest:
1. Animation of Saturn’s Big White Spot of 2010, created by the FOED and high resolution images: http://planetariafoed.wordpress.com
2. FOED website on the great storm produced in Saturn: http://planetariafoed.wordpress.com
3. Cassini (ESA/NASA) website: http://saturn.jpl.nasa.gov/

Contact Information

Enrique García Melendo
Fundació Observatori Esteve Duran / Institut de Ciències de l’Espai (CSIC-IEEC)
Email: egarcia@foed.org
Tel: +34 93 692 1761

Images

Figura-01-Cat-pet

Figure 1: Top image: The Great White Spot of Saturn observed by the Cassini spacecraft in orbit around Saturn on February 26, 2011. The expansion of the blue box on the overall image of the planet, on the right, shows the details of the head of the storm clouds formed by the convective cells. Credit: Mission Casini / JPL-Caltech/SSI.

Bottom image: map of the head winds of the storm where the arrows represent wind intensity typically up to a maximum of 500 km/h. In some areas, the winds can reach 600 km/h. Credit: FOED, UPV-EHU, UEMC, ICE (CSIC-IEEC).

Figura_02-Cat-pet

Figure 2: The top image shows a false-color detailed picture of Saturn’s storm. The bottom image is a computer simulation of the storm. The white clouds superimposed on a real background image of Saturn’s clouds are the result of the storm’s evolution in its interaction with the winds of Saturn. Credit: Cassini (NASA/JPL-Caltech/SSI).