Relationships between 10 Years of Radar-Observed Supercell Characteristics and Hail Potential
Relationships between 10 Years of Radar-Observed Supercell Characteristics and Hail Potential
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10年雷达观测的超级单体特征与冰雹可能性之间的关系
DOI：
10.1175/mwr-d-23-0019.1
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发表时间：
2023
影响因子：
3.2
通讯作者：
Kumjian, Matthew R.
中科院分区：
文献类型：
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作者：
Homeyer, Cameron R.;Murillo, Elisa M.;Kumjian, Matthew R.
超级单体风暴通常会导致严重的冰雹，这是美国和其他地方最昂贵的严重风暴危害。对这类风暴的雷达观测很常见，并被用来估计冰雹的大小和严重冰雹的发生。然而，雷达观测到的风暴特征和严重冰雹发生之间的许多既定的关系已经发现，使用的数据从几个风暴和其他雷达指标隔离。这项研究利用了美国10年的偏振多普勒雷达观测记录，根据最大冰雹大小评估和比较了数千个严重冰雹超级单体的雷达观测结果。与以往的研究结果一致，冰雹尺度的增大与高（≥50 dBZ）雷达反射率的增大、中高空气旋旋转（方位角切变）的增大、风暴顶辐散的增大以及低层（主要低于环境0°C）的差分反射率和共极相关系数的减小有关。新的见解包括增加垂直对齐的风暴中气旋冰雹的大小和多普勒速度谱宽度最小的高空附近的风暴中心，增加面积增加冰雹的大小，并认为增加上升气流的宽度。为了补充广泛的雷达分析，近风暴环境的再分析进行了比较，并指出，最大的环境差异存在于对流层中部（冰雹生长区），特别是垂直于风暴运动的风速。对未来改进基于雷达的冰雹大小估计提出了建议。
Supercell storms are commonly responsible for severe hail, which is the costliest severe storm hazard in the United States and elsewhere. Radar observations of such storms are common and have been leveraged to estimate hail size and severe hail occurrence. However, many established relationships between radar-observed storm characteristics and severe hail occurrence have been found using data from few storms and in isolation from other radar metrics. This study leverages a 10-yr record of polarimetric Doppler radar observations in the United States to evaluate and compare radar observations of thousands of severe hail–producing supercells based on their maximum hail size. In agreement with prior studies, it is found that increasing hail size relates to increasing volume of high (≥50 dBZ) radar reflectivity, increasing midaltitude mesocyclone rotation (azimuthal shear), increasing storm-top divergence, and decreased differential reflectivity and copolar correlation coefficient at low levels (mostly below the environmental 0°C level). New insights include increasing vertical alignment of the storm mesocyclone with increasing hail size and a Doppler velocity spectrum width minimum aloft near storm center that increases in area with increasing hail size and is argued to indicate increasing updraft width. To complement the extensive radar analysis, near-storm environments from reanalyses are compared and indicate that the greatest environmental differences exist in the middle troposphere (within the hail growth region), especially the wind speed perpendicular to storm motion. Recommendations are given for future improvements to radar-based hail-size estimation.