Comparison of the butterfly diagram based on the Shannon Entropy (top) and the butterfly diagram based on the Magnetic Field Strength (bottom), showing the evolution of level of longitudinal organization of the photospheric magnetic fields as a function of latitude and time.
HMI Science Nuggets: In recent years an increasing amount of evidence points to the crucial role of magnetically-modified Rossby waves in several solar phenomena. Rossby waves are large scale vortical oscillations that arise in rotating fluid/plasma systems as a result of the Coriolis force, being one of the most fundamental physical mechanisms in the understanding of Earths’s climate and weather. In Earth’s atmosphere one of their effects is to organize the spatial temporal formation of clouds and consequently rainfall and storms. Rays (paths) along which Rossby waves propagate are the origin of atmospheric stormtracks and teleconnection patterns.