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【学术报告】 Dr. L. Ruby Leung
阅读:474次 发布时间:2017-09-20 09:49


报告题目: Observation and Modeling of the Mesoscale Convective Systems and Their Large-scale Environments

报告人: Dr. L. Ruby Leung (Member of the National Academy of Engineering, AGU/AMS/AAAS Fellow, Pacific Northwest National Laboratory)

时间:  2017年9月25日 (周一)上午 10:30

邀请人:符淙斌院士 汪名怀教授

地点:大气科学楼D102报告厅

摘要:Mesoscale convective systems (MCSs) are important precipitation producers that account for 30-70% of warm season rainfall between the Rocky Mountains and Mississippi River and some 50-60% of tropical rainfall. Besides the tendency to produce floods, MCSs also carry with them a variety of attendant severe weather phenomena. In the past 35 years, observed increases in springtime total and extreme rainfall in the central United States are dominated by increased frequency and intensity of long-lasting MCSs. Understanding the environmental conditions producing long-lived MCSs is therefore a priority in determining how heavy precipitation events might change in character and location in a warmer climate. Continental-scale convection-permitting simulations of the warm seasons using the Weather Research and Forecasting (WRF) model reproduce realistic structure and frequency distribution of lifetime and event mean precipitation of MCSs over the central United States. Long-lived MCSs exhibit strong feedback to the environment through diabatic heating that helps to maintain them over a long period of time. A global variable resolution modeling framework, the Model for Prediction Across Scales (MPAS), with a non-hydrostatic dynamical core coupled to the Community Atmosphere Model (CAM) physics is being explored for convection permitting modeling of MCSs and their interactions with the large-scale circulation. The environmental ingredients of MCSs and convection permitting MPAS provide the conceptual and modeling frameworks needed for understanding and modeling the potential changes in MCSs and associated extremes in the future.