Department of Climate and Space Sciences and Engineering in the College of Engineering at the University of Michigan

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AOSS scientists develop innovative method to characterize the solar cycle

Posted: August 13, 2013

AOSS scientists develop innovative method to characterize the solar cycle

Research Fellow Liang Zhao and Associate Research Scientist Enrico Landi recently published a paper in the Astrophysical Journal that suggests only a portion of solar cycle activity is visible.

The paper was featured in the online newsletter Universe Today. According to Universe Today, the paper takes, “a fresh approach to model solar activity via looking at the 3-D dynamics heliospheric current sheet.”

The study, titled, “Two Novel Parameters to Evaluate the Global Complexity of the Sun’s Magnetic Field and Track the Solar Cycle,” was co-written by Sarah E. Gibson of the National Center for Atmospheric Research (NCAR).

The researchers compared data from 1975 through 2013 to characterize the Sun’s magnetic field boundary, known as HCS (heliospheric current sheet). By comparing the HCS value against previous sunspot numbers, which are numbers that correlate with a statistical estimation of the number of sunspots seen on the Earthward facing side of the Sun, the study suggests that “sunspot numbers may only tell one side of the story,” according to Universe Today.

“Looking at the HCS, we can see that the Sun began to act strange as early as 2003,” Zhao told Universe Today. “This current cycle as characterized by the monthly sunspot number started a year late, but in terms of HCS values, the maximum of cycle #24 occurred right on time, with a first peak in late 2011.”

Please click here to read the story in Universe Today.
Please click here to read the full abstract.

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