ANALYSIS ON THE PHYSICAL PARAMETER FIELD AND ECHO CHARACTERISTICS OF DOPPLER RADAR FOR A DESTRUCTIVE WIND IN HAINAN APRIL 11, 2016
ZHENG Yan
YU Xiao-ding
CAI Qin-bo
REN Fu-min
Abstract：A destructive wind event,with occurred on 11 April 2016 extensively and caused great damage and casualties in the north of Hainan Island,is analyzed based on Doppler radar,intensive automatic weather stations,and conventional meteorological stations.The result shows that an extended region of intense vertical upward motion in the front of a 500hPa trough,the left front of a low-level jet,the south of a low-level shear line,the south side of a ground stationary front and the diverging area of an upper-level jet provided favorable conditions for strong convective development.The convective storm formed in the conditions of moderate instability and convective available potential energy (CAPE),vertical profile of temperature and humidity with a dry and cold upper level,a wet and warm lower level,and a strong vertical wind shear.The typical features of hook echo and bow echo were found when the convective storm developed with strong wind,heavy hail and short time heavy rainfall.In this case,two storms (called storm A and B) developed into a supercell convective storm (storm C) with strong middle-altitude radial velocity.Storm B and C merged and formed a bow echo,and a mesocyclone with storm C became a mesoscale cyclonic eddy at the north part of the bow echo.A rear downdraft jet of the bow echo in the 0.2 to 2km height maintained the maximum radar radial velocity at 39m/s,and the entrainment of dry air resulted in the rapid evaporation of rain and the cooling of hail,which accelerated the descending air flow.A strong warm moist inflow in the front of the convective storm and a cold pool of the rear outflow obliquely coexisted with equivalent wind speed.Positive feedback of the gust front and its interaction with low-level vertical wind shear caused long-time maintenance and the enhancement of a self-organized mechanism made multiple-cell band storm and bow echo to strengthen and maintain.Multiple influential factors,such as the pre-existing meso-β-scale convergence shear on the ground and main echoes of convective storm moving eastward along the northern coast of Hainan Island,can keep multiple-cell band echo and bow echo strengthen and maintain for a long time.
Keywords：weather forecastthunderstormmultiple-cell band echobow echogust frontmeso-β-scale convergence shear
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 850-860 )