  We have measured the local and global statistics of singularity velocity, v,
and have related these through the spatial correlation function of v. The
distribution of v is a mixture of a mesoscopic distribution of global change in
the speckle pattern and the distribution for v for Gaussian random fields. When
v is normalized by the standard deviation of the fractional intensity change,
probability distributions and correlation function of v approach those for
random Gaussian fields. These results are directly analogous to the statistics
of transmitted intensity normalized by the total transmission and provide a
unified framework for understanding statistics of speckle evolution and
intensity.

Mesoscale and Nanoscale Physics;Disordered Systems and Neural Networks