  The lifetimes and length-scales for supergranular cells in active and
quiescent regions of the Solar chromosphere, and the relation between the two,
were studied using a time series of Ca II K filtergrams. The lifetimes, in
contrast to supergranular length scale and fractal dimension, show no
significant dependence on Solar latitude, suggesting that cell lifetimes are
independent of the differential rotation and a possible supergranular
super-rotation. The functional form of the relation was obtained guided by a
comparison of the distributions of the two supergranular parameters. We infer a
linear dependence of cell lifetime on area, which can be understood by the
assumption of the network's evolution via a diffusion of the magnetic field.
Our analysis suggests that the diffusion rate in quiet regions is about 10%
greater than in active regions.
