tailieunhanh - Báo cáo nghiên cứu khoa học " Large-scale circulation and precipitation over Vietnam region during a Mei-yu period: The role of the upper-level jet "

Sử dụng các dữ liệu tái phân tích NCAR-NCEP để mô phỏng trước Mei-yu xảy ra từ ngày 10-ngày 14 tháng 6 năm 2005, hệ thống mô hình hóa khí quyển khu vực (RAMS) cho mô hình mô phỏng cho thấy rằng phía trước Mei-yu có thể dẫn đến mưa lớn trên tất cả các khu vực Việt Nam . Nó cũng xuất hiện rằng sự phát triển của phía trước trùng hợp với việc tăng cường các máy bay phản lực trên cấp. Khi máy bay phản lực trên cấp là giả tạo làm suy yếu tại vùng ranh. | The Second International MAHASRI HyARC Workshop on Asian Monsoon and Water Cycle. 181- 190. Nhatrang Vietnam August 2011. Large-scale circulation and precipitation over Vietnam region during a Mei-yu period The role of the upper-level jet Nguyen Minh Truong Vu Thanh Hang Bui Hoang Hai and Cong Thanh Faculty of Hydrology Meteorology and Oceanography Hanoi University of Science 334 Nguyen Trai Thanh Xuan Hanoi Abstract. Using the NCAR-NCEP reanalysis data to simulate the Mei-yu front occurring from 10 to 14 June 2005 the Regional Atmospheric Modeling System RAMS model gives simulations which show that the Mei-yu front may lead to heavy rainfall over all Vietnam region. It also appears that the development of the front coincides with the intensification of the upper-level jet. When the upper-level jet is artificially weakened at the western and eastern boundary regions the amplitude of the East Asia cold trough is remarkably reduced over Japan and mesoscale disturbances are observed in the lower troposphere which associate with mesoscale changes in the simulation rainfall. These demonstrate that the upper-level jet may excite and steer mesoscale disturbances at lower levels as suggested by previous observational studies. Keywords Mei-yu front Mei-yu precipitation upper-level jet mesoscale disturbances. 1. Introduction The Mei-yu or Baiu in Japanese front is a well-known phenomenon embedded in the Asia summer monsoon which is a high-impact weather system and plays an important role in water resources in countries where it occurs. The Mei-yu studies may be divided into two common frameworks the Mei-yu season diagnosis and the Mei-yu front diagnosis. For the Mei-yu season diagnostic framework for example Wang et al. 2003 used a highly resolved regional climate model to simulate precipitation in the Mei-yu season from 26 April to 31 August 1998. Their 4-month simulations showed that rainfall associated with the Mei-yu front over the Yangtze River basin 26 -32 N 110 -122 E