Dynamics of solar mesogranulation

Details Dynamics of solar mesogranulation Dynamics of solar mesogranulation

Dec 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005a%26a...444..245l&link_type=abstract

Astronomy and Astrophysics, Volume 444, Issue 1, December II 2005, pp.245-255

Astronomy and Astrophysics

Astrophysics

7

Convection, Sun: Granulation, Sun: Photosphere

Scientific paper

Using a 45.5-h time series of photospheric flow fields generated from a set of high-resolution continuum images (SOHO/MDI) we analyze the dynamics of solar mesogranule features. The series was prepared applying a local correlation tracking algorithm with a 4.8´´ FWHM window. By computing 1-h running means in time steps of 10 min we generate 267 averaged divergence maps that are segmented to obtain binary maps. A tracking algorithm determines lifetimes and barycenter coordinates of regions of positive divergence defined as mesogranules (MGs). If we analyze features of lifetimes ≥1 h and of areas ≥5 Mm{2 we find a mean drift velocity of 304 m s-1 (with ± 1σ variation of 180 m s-1), a mean travel distance of 2.5 ± 1.8 Mm, a mean lifetime of 2.6 ± 1.8 h, and a 1/e decay time of 1.6 h for a total of 2022 MGs. The advective motion of MGs within supergranules is seen for 50 to 70% of the long-lived (≥4 h) MGs while the short-lived ones move irregularly. If only the long-lived MGs are further analyzed the drift velocities reduce to 207 m s-1 and the travel distances increase to 4.1 Mm on average, which is an appreciable fraction of the supergranular radius. The results are largely independent of the divergence segmentation level.

Affiliated with

Also associated with

No associations

Rating

Dynamics of solar mesogranulation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Dynamics of solar mesogranulation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamics of solar mesogranulation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1276381