The granulation pattern is overshoot of the convection zone into the photosphere. The evolution of average granule is estimated from 5 to 12 minutes, depending on the various research works. However, the granulation images often show the evidence for the features whose lifetime exceeds one of the granules. Roudier et al. (1997) detected features called "intergranular holes" with the lifetime of 45 min. The features in the granulation that persisted up to over 2.5 hours were observed by Hoekzema, Brandt and Rutten (1998) and Hoekzema and Brandt (2000). A form of the long-term persistence related to a spatial structuring was observed in the granulation images averaged over the time interval of several hours. Getling and Brandt (2002), Getling (2006) and Brandt and Getling (2008) observed that an averaged brightness field consist of the bright shapes against darker background. Those features form the long-lived quasi-regular concentric rings or parallel strips, 'ridges' and 'trenches'. Getling and Buchnev (2007) showed with the algorithmic treatment that the patterns of those alternating dark and bright lanes are ubiquitous in the averaged granulation images.

Several authors observed formation of the mesogranular - scaled clusters (Dialetis et al., 1988; Muller, Roudier and Vigneau, 1990). Later stated that there is a plausible relationship between clusters and mesogranules. Baudin, Molowny-Horas and Koutchmy (1997) showed that the supergranulation makes an imprint on the granulation pattern.

So far, in the low photosphere, it is considered that up-flows are usually brighter, while down-flows are darker. Following this premise the Getling and Buchnev (2007) and Brandt and Getling (2008) assume that the structures they observed reflect the presence of the roll convection in the upper convection zone. Those systems should form the fine structure of the mesogranular and supergranular flows.

Getling and Brandt (2002) and Brant and Getling (2008) noted the slow decrease in the RMS contrast of the averaged images with the averaging time. This was taken as the argument for the persistence of long-lived features. However, Rast (2002) stated that the quasi-regular structures detected in the granular patterns by Getling and Brandt (2002) are of statistical nature and do not reflect the structure of real flows.  

Images show the granulation pattern. Left one shows the granulation in one instance of the data cube, while the right one shows the integrated image of the granulation over the 2.5 hours.