Regularities in the distribution of solar activity in time and on the solar surface

From the daily sums of sunspot areas (Greenwich) we demonstrate some regularities in the development of solar activity during the four cycles with the lowest activity (Nos. 13 - 16). Most striking is the repetion (after intervals of many years) of long-lasting segments (of duration around 2 years) of daily area curves with the same time sequence and amplitude distribution of activity impulses and their packages.

We also examined the distribution and concentration of the solar magnetic fields from the Wilcox observatory synoptic charts for the whole period of their existing (May 1976 - February 2006). We divided them into several latitudinal zones (+/- 20, +/-(20-40), +/- 40 and =/- 60 degrees), studying the changes of their various structures, density, etc. These sets of maps demonstrate striking regularity in the photospheric magnetic field distribution with time, continuous existence of active, or better "characteristic magnetic longitudes" and their longitudinal shift with three main rotational periods of 26.8; 28.2 and 27.14 days. They show formation of specific structures of background weaker fields, connected with the development of activity complexes, polarity alternation, etc.

We discuss the possible sources and modes of found regularities in the solar activity modulation.