Differential rotation and giant cell circulation of solar Ca+-network

New results obtained from high precision computer controlled tracings of ca. 400 bright Ca+-mottles made during summer 1975 are reported. In particular, the existence of a giant circulation pattern in the equatorial zone was looked for. The authors find for the differential rotation: ω=13.93 - 2.90 sin2 B (deg/day, sidereal) when combining the new measurements with those obtained in 1974. Observations from 26th April until June 19th give strong evidence that at that time four giant circulation cells, crossing the solar equator, (i.e. a nonaxisymmetric velocity field pattern with respect to the solar equator) did exist. This yields two more rapid and two slower rotating sectors with Δγ=+-80 m s-1. These giant cells transport angular momentum towards the equator. (Auth.)