The hemispheric sign rule of current helicity during the rising phase of cycle 23

We compute the signs of two different current helicity parameters (i.e., alpha (best) and H-c) for 87 active regions during the rise of cycle 23. The results indicate that 59% of the active regions in the northern hemisphere have negative alpha (best) and 65% in the southern hemisphere have positive. This is consistent with that of the cycle 22. However, the helicity parameter H-c shows a weaker opposite hemispheric preference in the new solar cycle. Possible reasons are discussed.