APL Colloquium

October 9, 2019

Colloquium Topic: How the Hemispheric Polar Field Reversal Sets the Timing and Shape of the Solar Cycle

The solar cycle is a phenomenon that simultaneously presents a significant level of randomness, and an incredible regularity.  This dichotomy lies at the root of the impossibility of making multi-cycle predictions, but the remarkable capability we have of pinning down a cycle's properties once its underway.  One of the most important pieces of information that is currently used for solar cycle prediction is the strength of the polar fields during the minimum prior to the predicted cycle.  However, we only have direct measurements of the polar fields during the last 45 years and they paint an incomplete, and overly simplified, picture of this important relationship.

In this presentation I take advantage of a century of polar faculae measurements (as a proxy of polar magnetic flux), to illustrate how the dynamics of polar field reversal, the interaction between the Northern and Southern hemispheric cycles, and the interaction of each cycle with the one that came before, give shape to each solar cycle in a remarkably regular way.  We will discuss how the polar field may not be the only determinant of the observed cycle amplitude and how this discrepancy comes to be.  Then we will discuss how the moment of polar field reversal plays a critical role on timing the onset of the next solar cycle.  Finally, we will discuss how all this can be put together to make better and more detailed solar cycle predictions, and the kind of information that he next generation of model-driven cycle predictions needs to strive for to enable earlier and better cycle predictions.

Colloquium Speaker: Andrés Muñoz-Jaramillo

Andrés Muñoz-Jaramillo is originally from Colombia, South America. His research aims to understand and forecast the solar magnetic cycle, space weather, and their impact on solar variability and humanity’s technological infrastructure.

Andrés did his undergraduate work in Columbia at the Universidad de los Andes with a double major in Physics and Electronic Engineering. He came to the US in 2003 for an REU (Research Experience for Undergraduates) program in solar physics at Montana State University. Andrés received his PhD from Montana State University in 2010. He then did research as a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics through 2011, and transitioned to a Jack Eddy Fellowship until 2013. Andrés joined Montana State University in 2013 as a Research Scientist and then moved to Georgia State University in 2015. 

Andrés is currently a Senior Research Scientist at the Southwest Research Institute. He is an expert on the Solar Dynamo and Solar Cycle studies, and since 2017 has been a mentor at NASA's Frontier Development Laboratory with the aim of applying Deep Learning solutions to Heliophysics problems.