Balloon borne sensors have been used at the VLT observatory to
monitor the temporal coherence of the atmosphere. From such data coupled
with statistics on wind velocity vertical profiles, we may
estimate (or even forecast) the
characteristics (ps file).
However, the need for a real-time monitoring device is clear, in
particular with the development of observations coupled to adaptive
optics system. This is a project in development in the frame of the VLT
Astronomical Site Monitor (ASM). It aims at measuring the average and
the rms of the transverse velocity of the wavefront perturbations
following the technique described in the paper by Lopez  below.