Time-Latitude Distribution of Prominences for 10 Solar Cycles: A study using Kodaikanal, Meudon and Kanzelhohe Data

TL;DR

This study analyzes the long-term latitudinal distribution of solar prominences over 10 solar cycles using historical and recent datasets, revealing pole-ward migration patterns and their acceleration near high latitudes, which are crucial for understanding polar field reversals.

Contribution

It introduces an automated method to identify prominence locations across multiple datasets and separates migration rates during different phases, providing new insights into solar cycle dynamics.

Findings

Pole-ward migration of prominences observed in all cycles.

Acceleration in migration near ±70° latitude.

Migration rates offer insights into polar field build-up.

Abstract

Solar prominences are structures of importance because of their role in polar field reversal. We study the long-term variation of the time latitude distribution of solar prominences in this article. To accomplish this, we primarily used the digitised disc-blocked Ca II K spectroheliograms as recorded from Kodaikanal Solar Observatory for the period of 1906 -- 2002. For improving the data statistics we included full disc H_alpha images from Meudon and Kanzelhohe Observatory which are available after 1980. We developed an automated technique to identify the latitudinal locations of prominences in daily images from all three datasets. Derived time-latitude distribution clearly depicted pole-ward migration of prominence structures for 10 cycles (15-24). Unlike previous studies, we separated the rate of pole-ward migration during on-set and near pole, using piece-wise linear fits. In most cases, we found acceleration in pole-ward migration with the change occurring near +/- 70 degree latitudes. The derived migration rates for such large number of solar cycles can provide important inputs towards understanding polar field build-up process.