THE GRAND SOLAR MINIMA AND THE SOLAR DYNAMO

Both the direct sunspot observations and the indirect solar activity proxies indicate the existences of the solar grand minima during which time the solar activities are greatly reduced. They are usually coincided with periods of lower-than-average global temperatures. The existences of the grand minima pose a challenge for the solar dynamo. The main features of the grand minima and the new dynamo models to explain their existences will be reviewed in the paper.