辽宁省温带气旋龙卷的环境参数特征

基于上海青浦双偏振雷达、武汉多普勒天气雷达、新一代天气雷达组网拼图、地面加密自动气象站和ERA5再分析等数据，对2021年5月14日夜间苏州、武汉相继出现的致灾严重的龙卷天气过程，从天气背景、地面触发机制、雷达探测特征和环境参数等方面进行了对比分析，结果表明：(1) 苏州、武汉两地龙卷均发生在西南暖湿气流强迫背景下，低层高温高湿，均受到低空急流和超低空急流影响，但两地龙卷发生位置与对应的急流位置不同，苏州龙卷西侧对应东侧急流出口区，武汉龙卷正好对应西侧急流出口区；(2) 苏州龙卷是由阵风锋引起的辐合线配合强度适宜的弱冷池触发的；武汉龙卷发生时地面存在中尺度辐合中心和弱冷池；(3) 两地龙卷均发生在孤立右移超级单体伴随低层中气旋突然加强之时，龙卷涡旋特征(TVS)分别出现在苏州龙卷和武汉龙卷发生前2 min和3 min；(4) 有别于美国龙卷发生的环境条件，苏州龙卷发生在高的对流有效位能、较低的抬升凝结高度和对流抑制能量以及中等偏弱的风暴相对螺旋度和垂直风切变条件下；武汉龙卷则发生在弱的对流有效位能、较低的抬升凝结高度、较高的对流抑制能量以及强的风暴相对螺旋度和垂直风切变条件下。比较而言，两地龙卷发生前和发生时，苏州龙卷的热力条件较好、动力条件中等偏弱，而武汉龙卷的动力条件较好、热力条件偏弱，可见两地龙卷均发生在热力和动力条件互补的环境下。

Environmental characteristics of extratropical cyclone tornadoes in Liaoning

Based on datasets from Shanghai Qingpu dual-polarized radar, Wuhan Doppler weather radar, new generation weather radar network mosaic, ground encrypted automatic weather station, and ERA5 reanalysis, a comparative analysis was conducted on the severe tornado weather processes that occurred in Suzhou and Wuhan on the night of 14 May 2021 from the aspects of weather background, ground triggering mechanism, radar detection characteristics, and environmental parameters. Results are as follows. (1) Both tornadoes in Suzhou and Wuhan occurred under the forced background of southwest warm and humid airflow, with low temperature and high humidity in the lower layer being affected by low-level and ultra-low-level jet streams. However, the location of the tornado in each of the two places was different from the corresponding jet stream location. The western side of the Suzhou tornado corresponded to the exit area of the eastern jet stream, while the Wuhan tornado corresponded to the exit area of the western jet stream. (2) The Suzhou tornado was triggered by the convergence line caused by gust fronts and a weak cold pool with appropriate intensity. Nevertheless, there was a mesoscale convergence center and a weak cold pool on the ground. (3) Tornadoes in both places occurred when the isolated rightward-moving supercells were accompanied by a suddenly strengthened low-level mesocyclone. And tornadic vortex signature (TVS) appeared 2 min and 3 min before the Suzhou tornado and Wuhan tornado, respectively. (4) Different from the environmental conditions of tornadoes occurring in the United States, the Suzhou tornado appeared under the conditions of high convective available potential energy, low lifting condensation height, convective inhibition energy, and medium to weak storm-relative helicity and vertical wind shear. Wuhan tornado occurred under the conditions of weak convective available potential energy, low lifting condensation height, high convective inhibition energy, and strong storm-relative helicity and vertical wind shear. By comparison, before and during the occurrence of tornadoes in the two regions, the thermal condition of the Suzhou tornado was favorable and the dynamic conditions were standard or even unfavorable. However, for the Wuhan tornado, the thermal condition was relatively weak, while the dynamic conditions were favorable. It is indicated that both tornadoes occurred in environments with complementary thermal and dynamic conditions.