2016年夏季如东一次EF2级龙卷多普勒天气雷达特征分析

利用常规观测资料、NCEP 1°×1°再分析资料、南通多普勒天气雷达资料及GR2analyst分析软件，对2016年7月5日发生在江苏省如东县的一次EF2级超级单体龙卷过程进行特征分析。结果显示：此次龙卷发生在高低空均为一致的西南暖湿气流中，没有明显干冷空气侵入，中低层存在切变、急流，超低空急流，地面有辐合中心；大气具有中等大小的热力不稳定能量、0~1 km强垂直风切变、充足的水汽条件、较低的抬升凝结高度以及较强的辐合上升运动，为此次龙卷过程提供有利的背景条件。当出现连续体扫的中气旋、钩状回波，并且强回波区向移动方向一侧倾斜、垂直剖面存在穹隆结构和有界弱回波区时，在钩状回波处最容易产生龙卷。GRanalyst三维显示中出现的空洞结构，表明超级单体在此处产生强烈涡旋，有利于龙卷的产生；对称的正负速度区中旋转速度持续增大，并且不断向下发展，低仰角探测到紧邻的速度对时，强中气旋也相应出现向下延伸和迅速的收缩，预示着龙卷的发生，为龙卷预报提供一定的指示作用。

Analysis on the doppler weather radar characteristics of EF2 tornado in Rudong during the summer 2016

By using the conventional observation data, NCEP reanalysis data, Nantong Doppler weather radar detection data and GR2 analyst, a EF2 tornado process occurred in Rudong county of Jiangsu province on 5 July 2016 was analyzed.The results show that the tornado occurred in the specific weather situation, which with strong instability energy, abundant moisture, strong vertical wind shear and low Lifting Condensation Level (LCL). When the sweep continuum cyclone, hook echo, and the strong echo area to the lower side of slope, the vertical profile has dome structure and bounded weak echo area, which is easiest to produce in the tornado hook echo. Hollow structure in GRanalyst three-dimensional display shows that the supercell here produced a strong vortex, which is conducive to the tornado; when the rotating speed in the symmetrical positive and negative areas continued to increase and develop downward, the low elevation detected the close speed, the strong mesocyclone also extends downward and appears rapid contraction, indicating a tornado occurrence and providing some indication for tornado forecasting.