Relationship between horizontal flow velocity and cell lifetime for supergranulation from SOHO Dopplergrams

Abstract

A study of 50 supergranular cells obtained from Solar and Heliospheric Observatory (SOHO) Dopplergrams was undertaken in order to investigate the relationship between the lifetime (T) and the horizontal flow velocity (vh) of the cells. For this sample, we find that the two parameters are correlated with a relation vh~T1/2 and T is identified by the eddy turnover time. This is in agreement with the turbulent convective model of the solar atmosphere, where the velocity spectrum of the supergranular field, given by the relation vh~L1/3, can be identified with the Kolmogorov spectrum for the eddy size L.