Applications - Surface Based Remote Sensing of the Atmospheric Boundary Layer - page 130

Fig. 4.36 Sequence of
Doppler wind LIDAR
observations of a moving
thunderstorm gust front. The
LIDAR was positioned at
0.0 km (Fig. 7 from Intrieri
et al. 1990 )
motion at the surface. The field of arrows clearly shows horizontal vortex rolls that
are associated with the head of the density flow. Time-height cross sections from
vertically pointing RADAR observations of thunderstorm gust fronts and outflows
allow for a direct detailed analysis of vertical velocities in these outflows (Martner
1997 ). The maximum updraft, of almost 10 m s − 1 , was measured in the gust front at
1.35 km above ground level and was followed by equally strong downward motion
only 1 min later at a slightly higher altitude. The observations support the earlier use
of the continuity method for deriving the basic pattern of vertical motions in density
currents from quasi-horizontal scan data.
4.5.3 Land and Sea Breeze
Remote-sensing data from marine boundary layers are rare. This is because plat-
forms for the installation of remote-sensing instrumentation are rare. Vertical
pointing remote-sensing devices usually need fixed platforms. Deviations of a few
degrees from the true vertical direction give large errors, especially if radial wind
components are observed. A few experiments with SODARs on board of ships and