|On July 31, 1996 Typhoon Herb roared across Northern
Taiwan resulting in the loss of many lives and damage to property
due to high winds, flooding, and landslides. One of the locations
receiving heavy damage was the WSR-88D radar facility located at the
Northern tip of Taiwan, 30 KM east northeast of Taipei. The facility,
operated by Taiwan's Central Weather Bureau, collected reflectivity
and velocity data as the Typhoon approached and was forced to shut
down as the eye of the storm grew closer and the threat of water damage
to the radar electronics increased. Eight hours after the facility
shut down, high winds ripped the fiber glass panels from the radar
instrumentation and flung them down the hillside. Doppler Radar analysis
of the storm showed peak wind speeds of 82 m/s at the 1 km level.
Below we show a comparison between observed data collected by the
Radar installation before it was shut down and MM5 model data generated
by researchers at the National Center for Atmospheric Research. One
of the unique characteristics of Typhoon Herb is its elliptical shaped
In the observed data there is a
stationary hole directly above the radar location at the center
of the image. This hole represents missing data which are an artifact
of the conical radar beams that project from the radar source.
The model data generated by the MM5
model is nonhydrostatic and uses a terrain-following sigma coordinate.
The model physics include parameterization for the surface and planetary
boundary layer, and cloud microphysics. It also includes prediction
of rain water/snow, cloud water/ice and graupel, cumulus convection,
and atmospheric radiation.