Rossby Waves On The Sun

Friday, April 14, 2017

Space weather forecasting capability is six decades behind terrestrial weather forecasting," you will often hear at gatherings of scientists determined to understand the connections between our star and our home on Earth. It is an accurate statement in terms of capability. Significant breakthroughs in the latter were driven by the ability to study our atmosphere from a global perspective, from space with the dawn of the satellite age.

Rossby waves on the Sun image
Rossby waves on the Sun

HAO-led research published in Nature Astronomy demonstrated that the same kind of large-scale planetary waves that meander through the atmosphere high above Earth's surface may also exist on the Sun. Just as the large-scale waves that form on Earth, known as Rossby waves, influence our weather patterns, the waves discovered on the Sun appear to be intimately tied to solar activity, including the formation of sunspots, active regions, and the eruption of solar flares.

The research exploited data from the twin STEREO and SDO spacecraft that, f​o​r the first time, allowed us to see the entire solar atmosphere simultaneously. The team included two undergraduate students in the Boulder area's Research Experience for Undergraduates​ (REU) program, William Cramer and Manuel Marcano. ​Analyzing the same features in the three datasets and combining the information contained was their challenge. They quickly realized that patterns in the data persisted that are related to the Sun's magnetic activity behaved in the same way as those on the Earth. The correspondence can be seen in this short animation prepared by NASA​ to accompany the paper​.

By exploiting the global perspective of the Sun, this research and the subsequent analysis of the unique STEREO/SDO dataset, may lead to significant advances in our ability to study the magnetic phenomena that control space weather. Understanding the origins and behavior of coronal holes, active regions and other magnetic features are essential to solving the space weather forecasting puzzle. The hope is that this knowledge, and the application of meteorological analysis techniques to the data will help close the 60 year conceptual gap.

​In a ​"it's a small world" twist to the work, the NASA news release was written by an REU classmate of William and Manuel's, Mara Johnson-Groh now of NASA's Goddard Space Flight Center. Here is a small feature of the three students back in 2013. "It is fantastic to see these young scientists flourish on their chosen path, watching them grow as communicators and scientists" said HAO Director Scott McIntosh, lead author of the study and mentor to William and Manuel.

If you want to play with the STEREO/SDO dataset, the HAO team has worked with their colleagues in NCAR's Computational Information Systems Laboratory (CISL) to include it in the recent release of their free "METEO AR" and "METEO VR" smartphone apps. You can find out more about those apps here. Remember that you'll also need the accompanying "Science Sheet".