Solar Cycle Propagation, Memory, and Prediction: Insights from a Century of Magnetic Proxies

Abstract

The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and the Earth's upper atmosphere (commonly referred to as space weather). These changes have a direct impact on the lifetime of space-based assets and can create hazards to astronauts in space. In recent years there has been an effort to develop accurate solar cycle predictions (with aims at predicting the long-term evolution of space weather), leading to nearly a hundred widely spread predictions for the amplitude of solar cycle 24. A major contributor to the disagreement is the lack of direct long-term databases covering different components of the solar magnetic field (toroidal vs.\ poloidal). Here we use sunspot area and polar faculae measurements spanning a full century (as our toroidal and poloidal field proxies), to study solar cycle propagation, memory, and prediction. Our results substantiate predictions based on the polar magnetic fields, whereas we find sunspot area to be uncorrelated to cycle amplitude unless multiplied by area-weighted average tilt. This suggests that the joint assimilation of tilt and sunspot area is a better choice (with aims to cycle prediction) than sunspot area alone, and adds to the evidence in favor of active region emergence and decay as the main mechanism of poloidal field generation (i.e. the Babcock-Leighton mechanism). Finally, by looking at the correlation between our poloidal and toroidal proxies across multiple cycles, we find solar cycle memory to be limited to only one cycle.

7 pages, 5 figures

References in corpus (6)

• Predicting solar cycle 24 with a solar dynamo model
• Exploring the Physical Basis of Solar Cycle Predictions: Flux Transport Dynamics and Persistence of Memory in Advection versus Diffusion Dominated Solar Convection Zones
• Calibrating 100 Years of Polar Faculae Measurements: Implications for the Evolution of the Heliospheric Magnetic Field
• Turbulent magnetic pumping in a Babcock-Leighton solar dynamo model
• Prediction of Sunspot Cycles by Data Assimilation Method
• Turbulent Pumping of Magnetic Flux Reduces Solar Cycle Memory and thus Impacts Predictability of the Sun's Activity

Cited by in corpus (6)

• The crucial role of surface magnetic fields for the solar dynamo
• Magnetic Flux Transport at the Solar Surface
• Hemispheric Coupling: Comparing Dynamo Simulations and Observations
• Source of a Prominent Poleward Surge During Solar Cycle 24
• Occurrence of high-speed solar wind streams over the Grand Modern Maximum
• Meridional circulation dynamics from 3D MHD global simulations of solar convection