Peculiar behavior of solar polar fields during solar cycles 21-23: Correlation with meridional flow speed

摘要

We have examined solar polar fields during the solar cycles 21-23 using both ground and space based synoptic magnetograms. It has been shown that the unsigned polar fields in the latitude range (78°-90°) show a steady decline starting ~1995-1996 till the maximum of cycle 23. We also find that the long term changes in the unsigned polar fields at higher latitudes are well correlated with changes in the surface meridional flow speed that have been reported for the cycle 23.