  We analyse the topology of photospheric magnetic fields and sub-photospheric
flows of several active regions (ARs) that are observed during the peak to
descending phase of the solar cycle 23. Our analysis shows clear evidence of
hemispheric preferences in all the topological parameters such as the magnetic,
current and kinetic helicities, and the 'curl-divergence'. We found that
68\%(67\%) ARs in the northern (southern) hemisphere with negative (positive)
magnetic helicities. Same hemispheric preference sign is found for the current
helicities in 68\%(68\%) ARs. The hemispheric preferences are found to exist
statistically for all the time except in few ARs observed during the peak and
the end phases of the solar cycle. This means that magnetic fields are
dominantly left(right)-helical in scales smaller than individual ARs of
northern(southern) hemisphere. We found that magnetic and current helicities
parameters show equator-ward propagation similar to the sunspot cycle. The
kinetic helicity showed similar hemispheric trend to that of magnetic and
current helicity parameters. There are 65\%(56\%) ARs with negative (positive)
kinetic helicity as well as divergence-curl, at the depth of 2.4\,Mm, in the
northern (southern) hemisphere. The hemispheric distribution of the kinetic
helicity becomes more evident at larger depths, e.g., 69\%(67\%) at the depth
of 12.6\,Mm. Similar hemispheric trend of kinetic helicity to that of the
current helicity supports the mean field dynamo model. We also found that the
hemispheric distribution of all the parameters increases with the field
strength of ARs. The topology of photospheric magnetic fields and near surface
sub-photospheric flow fields did not show good association but the correlation
between them enhances with depths which could be indicating more aligned flows
at deeper layers of ARs.
