NCAR JOINT EOL/MMM SEMINAR
Use of radar data to improve
TC intensity forecasts
Jin-Luen
(Jim) Lee
NOAA/OAR, Earth System
Research Laboratory
Global Systems Division
Hurricane track forecasts improve steadily over the
last several decades. However, intensity
forecasts show very little improvement over the last decade because small-scale
inner-core circulation can not be properly resolved by satellite observations. To improve intensity forecasts, it is
important to use high-resolution Doppler radar data to properly initialize
inner-core circulation for high-resolution numerical models. A technique is developed for initialization
of a hurricane vortex using horizontal velocities through a deep layer of the
atmosphere obtained from Doppler radar.
The technique uses two new innovations.
The first is the use of the mesoscale vorticity equation to diagnose the vertical velocity and
divergent wind. The second is the use of
the Bounded Derivative Initialization to obtain two dynamic constraints, one
each for gravity and sound waves. With
the fast waves controlled, a nonhydrostatic model can
be initialized to allow a smooth and balanced start. The technique is tested using the 1.5 km
resolution MM5 model with GBVTD retrieved radar wind fields from Hurricane
Danny as it approached the
.
Refreshments
NCAR-Foothills Laboratory
Bldg 2 Auditorium (Rm.1022)