Mean diurnal variations of cosmic ray intensity as measured by Andyrchi air shower array and Baksan underground scintillation telescope

The results of measuring diurnal variations of extensive air showers with energy above 100 TeV detected by the Andyrchi air shower array in 1995-2002 are presented. It is shown that solar diurnal wave of intensity is formed by pressure variations and Compton-Getting effect (due to the orbital motion of the Earth). The data on cosmic ray anisotropy of the Baksan underground scintillation telescope (BUST) are also presented for energies above 2.5 TeV covering the period 1982-1998. The diurnal sidereal wave measured by both Andyrchi and BUST is due to anisotropy of the cosmic rays.