地球惑星科学専攻 地球科学輻合部特別講演会

講演題名：
Impact of Typhoon on Ocean in the Pacific (ITOP) 2010: High-Resolution
Coupled Modeling

講演者：
Prof. Shuyi S. Chen
(RSMAS/University of Miami, Miami, Florida)

日時・場所:
2010年5月20日(木) 16：00〜17：30
京都大学理学部1号館5階563号室

講演要旨:
Rapid intensification and decay in hurricanes and typhoons continue to be
a major challenge for storm predictions over the Atlantic and Pacific
basins.  It highlights the urgent need for a better understanding of
factors contributing to rapid intensity change and for development of the
corresponding advanced prediction models to improve intensity forecasts.
The lack of skill in forecasts of storm structure and intensity may be
attributed in part to deficiencies in the current prediction models:
insufficient grid resolution, inadequate model physics such as
PBL/surface and microphysics, and the lack of full coupling to a dynamic
ocean.  The extreme high winds, intense rainfall, large ocean waves, and
copious sea spray in tropical cyclones push the surface-exchange
parameters for temperature, water vapor, and momentum into untested
regimes.  The main objectives of the Impact of Typhoons on Ocean in the
Pacific (ITOP) are to better understand and observe typhoons and their
impact on the ocean over the western North Pacific and to improve
prediction of tropical cyclone formation and development in the next
generation research and operational coupled atmosphere-wave-ocean
prediction systems. The recent modeling effort at the University of Miami
is to develop and test a fully coupled atmosphere-wave-ocean modeling
system that is capable of resolving the eye and eyewall in a tropical
cyclone at ~1 km grid resolution.   The lack of in situ observation to
get accurate initial conditions for high-resolution coupled models
presents another major challenge for storm prediction in real time,
especially in the early stage of development. This study aims to better
identify and quantify both convective and large-scale properties of
developing cases prior to tropical cyclogenesis as well as significant
non-developing cases using an objective cloud-cluster tracking method.
An objective means of identifying and tracking developing and
non-developing cases has been a major gap in the literature.
Improvements in initial conditions for mature storms rest on the use of
airborne and satellite observations in high-resolution data assimilation
systems and applications of advanced assimilation technique in tropical
cyclones.  This talk aims to provide an overview of these new challenges
using high-resolution coupled model simulations and forecasts of
hurricanes and typhoons in 2003-05 and 2008-09.  Several cases were
observed extensively by recent field programs, namely, the Coupled
Boundary Layer Air-Sea Transfer (CBLAST)-Hurricane in 2003-2004, the
Hurricane Rainbands and Intensity Change Experiment (RAINEX) in 2005, and
some limited observations from the Tropical Cyclone Structure (TCS-08)
over the West Pacific.

問い合わせ先:
重 尚一