ИСТИНА

The relation between the solar wind velocity and the areas of low-latitude coronal holes (CHs) during solar cycle 23 was investigated. Low-latitude CHs areas were calculated based on SOHO/EIT observation in 195Å and 284Å channels and STEREO observation in 195Å channel using a special numerical algorithm. The correlation between the daily average solar-wind velocities and the calculated CHs areas at different phases of the solar cycle was analyzed. The yearly correlation coefficient values from 0 for 2001 year up to 0.7 for 2003 year were found. Physical explanation of this fact is suggested in relation to the sporadic activity of the Sun. The calculated CHs areas were compared with the mean solar magnetic field measured by SOHO/MDI and ground based observatories. CHs areas measured using SOHO/EIT and STEREO observations in 284Å and in 195Å channels are compared. Elements of difference and likeness in character of correlation have been revealed in these spectral ranges. CHs areas in different spectral ranges can be used for filling data gaps and for investigation structures of the closing and opening magnetic field configuration in the vicinity of CHs. Special periods of time when active regions resided inside CHs are investigated with the results showing the influence of this situation on the solar wind properties. The neural network algorithm for prediction of the daily values of the solar wind velocity by the area of low-latitude CHs was developed and successfully used. A significant feature of such approach is the possibility of search for non-linear interconnections between CHs and the values of solar wind velocity.