Single-Doppler Radar Observations of a High Precipitation Supercell Accompanying the 12 April 2003 Severe Squall Line in Fujian Province  

作　　者：潘玉洁 赵坤 潘益农 

机构地区：[1]Key Laboratory of Mesoscale Severe Weather of Ministry of Education [2]School of Atmospheric Sciences Nanjing University

出　　处：《Acta meteorologica Sinica》2010年第1期50-65,共16页

基　　金：Supported by the National Special Fund for Meteorology(GYHY200706033);National Natural Science Foundation of China under Grant Nos.40505004,40405012,and 40333025;National Fundamental Research"973"Program of China(2004CB418301); the Natioual Meteorological Center of China TIGGE Program(GYHY(QX) 2007-232 6-1)

摘　　要：In this study,single Doppler radar data were used to examine the structure and evolution of a high precipitation（HP） supercell embedded in a cold front near Jianyang,Fujian Province on 12 April 2003.The synoptic environment was characterized by high humidity at low levels,moderate CAPE（convective available potential energy;1601 J kg^（-1））,moderate wind shear（22 m s^（-1） in 0-5 km）,and veering of the horizontal winds with height,similar to those HP supercells previously observed in midlatitudes.In addition,the calculated bulk Richardson number was only 16,suggesting favorable environmental conditions for supercell development. The documented storm was located at the leading edge of a squall line.It was initiated from a single cell at 0732 UTC.It evolved into a bow shape gradually,and then split into two separate storms along the storm motion direction through the apex of the bow echo.The left-moving storm dissipated rapidly, but the right-moving storm strengthened and evolved into an HP supercell,lasting for more than 1 h.The radar reflectivity of the HP supercell during its mature stage showed a typical low-level hook echo at the front flank of the storm with its maximum reflectivity beyond 70 dBZ.Above the hook echo,an elevated maximum reflectivity core accompanied by a bounded weak-echo region（BWER） and a down-shear echo overhanging aloft were clearly identified.The elevated BWER,marked by 40-50-dBZ reflectivity values,was surrounded by values of 60-70 dBZ.A well-defined mesocyclone lasted about 1 h and was collocated with the low-level WER and middle-level BWER.The radar-estimated time-height profiles of mesocyclone rotational velocity and diameter indicated that this mesocyclone formed initially at middle level,then deepened and strengthened rapidly with the vertical depth deeper than 8 km and rotational velocity stronger than 24 m s^（-1） at the mature stage,and later decayed rapidly.The GBVTD（ground-based velocity track display）-derived primary circulation showed that the maxiIn this study,single Doppler radar data were used to examine the structure and evolution of a high precipitation（HP） supercell embedded in a cold front near Jianyang,Fujian Province on 12 April 2003.The synoptic environment was characterized by high humidity at low levels,moderate CAPE（convective available potential energy;1601 J kg^（-1））,moderate wind shear（22 m s^（-1） in 0-5 km）,and veering of the horizontal winds with height,similar to those HP supercells previously observed in midlatitudes.In addition,the calculated bulk Richardson number was only 16,suggesting favorable environmental conditions for supercell development. The documented storm was located at the leading edge of a squall line.It was initiated from a single cell at 0732 UTC.It evolved into a bow shape gradually,and then split into two separate storms along the storm motion direction through the apex of the bow echo.The left-moving storm dissipated rapidly, but the right-moving storm strengthened and evolved into an HP supercell,lasting for more than 1 h.The radar reflectivity of the HP supercell during its mature stage showed a typical low-level hook echo at the front flank of the storm with its maximum reflectivity beyond 70 dBZ.Above the hook echo,an elevated maximum reflectivity core accompanied by a bounded weak-echo region（BWER） and a down-shear echo overhanging aloft were clearly identified.The elevated BWER,marked by 40-50-dBZ reflectivity values,was surrounded by values of 60-70 dBZ.A well-defined mesocyclone lasted about 1 h and was collocated with the low-level WER and middle-level BWER.The radar-estimated time-height profiles of mesocyclone rotational velocity and diameter indicated that this mesocyclone formed initially at middle level,then deepened and strengthened rapidly with the vertical depth deeper than 8 km and rotational velocity stronger than 24 m s^（-1） at the mature stage,and later decayed rapidly.The GBVTD（ground-based velocity track display）-derived primary circulation showed that the maxi

关 键 词：high precipitation（HP） supercell hook echo bounded weak echo region（BWER） MESOCYCLONE 

分 类 号：P412.25[天文地球—大气科学及气象学]