Impact of global warming on tropical cyclone structure change with a 20km-mesh high-resolution global model
Hiroyuki Murakami, AESTO/MRI, Tsukuba, Ibaraki, Japan; and A. Kitoh
In this study, 25-year consecutive climate simulations for both present-day and future warmed environment based on A1B scenario using a 20km-mesh high-resolution atmospheric general circulation model were conducted to explore structure change of tropical cyclones (TCs) influenced by the global warming.
During the present-day (future) simulation, 2073 (1655) TCs were formed globally. The large number of TCs was enough to discuss, with statical significance, the difference of TCs climatology regarding to frequency of formation, intensity, and mean structure of TC influenced by the global warming.
About 15-20% (20-35%) increase of surface wind speed (precipitation) was confirmed at the inner-core region within 100km from the center. The wind-speed strengthening of 0-10% reached from the center within the range of 600km in the radius. The large increase of wind speed was more remarkable in the mid-troposphere than at the surface. It was also confirmed that warm-core was strengthened at the upper-troposphere between 200 and 400 hPa vertical level. These changes were caused by the enhanced heating by deep convection and grid-scale condensation in the eyewall region.
These results indicate that TCs expands vertically as well as horizontally in the future warming environment.
Session 7B, Tropical cyclones
Tuesday, 13 January 2009, 3:30 PM-5:30 PM, Room 129B
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