Wednesday, 1 August 2001: 2:00 PM
observations and numerical simulations of tropopause PV trough filamentation and "Cut-Off" Low development over the North Pacific Ocean
During the period 3-7 February, a dramatic example of anticyclonic
Rossby-wave breaking occurred over the North Pacific ocean in association
with Rossby-wave energy propagation (downstream development) from
extratropical to tropical latitudes. The NOAA/G-4 weather reconnaissance
aircraft took measurements throughout the life cycle of this event by
deploying high-spatial resolution (50 km) GPS dropwindsondes on three
consecutive days The G-4 flights were tasked from Honolulu Hawaii in
corrdination with the NOAA/NCEP Winter-Storm Reconnaissance Program.
Onboard ozone measurements documented the intrusion of ozone-laded
stratospheric air as the upper PV anomaly narrowed from its initial
wave-like structure culminating in the formation of a tropopause-based cut
off cyclone vertically coupled to the lower-tropospheric warm-core
seclusion of the Kona Low. Hourly multi-spectral visible, infrared, and
water-vapor cloud and water vapor-drift winds and images provide a
temporally and spatially continuous documentation of the Kona low life
cycle. Total columnar ozone measurements from geostationary and polar
orbiting satellites provided a surrogate visualization of the evolution of
lower-stratospheric PV wave breaking, filamentation, and tropopause based
cut-off cyclone development. A high-resolution numerical simulation with
the NCAR/Penn. State multi-scale prediction model provides a realistic
replication of the observed event and is used to carry out dynamical and
physical process diagnostics of the role of tropopaue-based PV evolution
and tropospheric sensible and latent heating.
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