The goal of this paper is to investigate Reynolds stresses and to check if it is plausible that they are responsible for angular momentum transfer toward the solar equator .
We also analysed meridional velocity , rotation velocity residuals and correlation between the velocities .
We used sunspot groups position measurements from GPR ( Greenwich Photographic Result ) and SOON/USAF/NOAA ( Solar Observing Optical Network/United States Air Force/National Oceanic and Atmospheric Administration ) databases covering the period from 1878 until 2011 .
In order to calculate velocities we used daily motion of sunspot groups .
The sample was also limited to \pm 58°in Central Meridian Distance ( CMD ) in order to avoid solar limb effects .
We mainly investigated velocity patterns depending on solar cycle phase and latitude .
We found that meridional motion of sunspot groups is toward the centre of activity from all available latitudes and in all phases of the solar cycle .
The range of meridional velocities is \pm 10 m s ^ { -1 } .
Horizontal Reynolds stress is negative at all available latitudes and indicates that there is a minimum value ( q \approx - 3000 m ^ { 2 } s ^ { -2 } ) located at b \approx \pm 30 \degr .
In our convention this means that angular momentum is transported toward the solar equator in agreement with the observed rotational profile of the Sun .