摘要:为探究贵州省威宁地区雹暴过程中雹胚粒子的演变特征，本文在对X波段双线偏振雷达数据经过退折叠、滤波、自适应衰减订正后，运用Barnes插值方法对偏振参量进行插值，并结合模糊逻辑算法进行水成物粒子识别，然后对威宁县的两次典型雹暴过程进行了系统的分析，得到以下结论：（1）两次过程中高密度霰的来源均为冰晶聚合物和冻滴，低密度霰粒子的来源均为冰晶粒子；单体雹暴过程中高密度霰粒子对冰雹的产生贡献最大，多单体雹暴过程中低密度霰粒子对冰雹的产生贡献最大。（2）多单体雹暴中，衰减单体的高空辐合以及低空辐散对发展单体的雹胚形成有促进作用。（3）单体雹暴降雹前：低密度霰粒子数量近乎不变；由于冰晶聚合物增多使得消耗过冷水粒子速度加快，导致过冷水粒子减少，而且有部分高密度霰粒子坠落至地面，导致高密度霰粒子数量减少，每分钟减少的距离库数为10；降雹时：高密度霰粒子淞附过冷水粒子增长形成冰雹，导致高密度霰粒子减少，每分钟减少的距离库数为12.1；而在“贝吉龙过程”（即Wegener-Bergeron-Findeisen过程，简称WBF）以及冰晶聚合物的淞附作用下，低密度霰粒子迅速增多，每分钟增加的距离库数为36；降雹后：低密度霰粒子坠落，数量快速减少，每分钟减少的距离库数为36.6；低密度霰粒子在下降过程中淞附过冷水、冰晶聚合物等粒子转化成高密度霰粒子，导致高密度霰粒子总量几乎不变，每分钟增加的距离库数为2。（4）多单体雹暴降雹前与单体雹暴类似，不同的是在消散单体的促进作用下，发展单体的发展速度、雹胚数量、回波强度均高于单体雹暴；降雹时：低密度霰粒子在下落过程中淞附过冷水滴增长形成冰雹，导致数量迅速减少，每分钟减少的距离库数为62.6；高密度霰粒子数量增加，每分钟增的距离库数为16.5；由成熟到降雹的时间比单体雹暴长15分钟左右；降雹后与单体雹暴类似。（5）通过对威宁地区雹暴机制的分析，分别建立了单体雹暴、多单体雹暴的概念模型。本文针对两种典型雹暴的各个过程中雹胚的演变特征研究得到了初步结果，这对于雹暴预警、预报以及人工消雹具有较高的应用价值。
关键词:粒子识别/
X波段双线偏振雷达/
微物理/
雹胚
Abstract:In order to explore the evolution characteristics of hail embryo particles during hailstorm in Weining area, the Barnes interpolation method was used to interpolate polarization parameters after unfolding, filtering, and adaptive attenuation correction of X-band dual polarization radar data. The fuzzy logic algorithm was used to identify the particles of the aquatic objects, and two typical hailstorm processes in Weining County were then systematically analyzed. The following conclusions were obtained: (1) The sources of high-density graupel were aggregates and frozen drops during both processes, and the sources of low-density graupel particles were ice crystal. High-density graupel particles contributed the most to the production of hail during a single-cell hailstorm, while low-density graupel particles contributed the most to the production of hail during a multicell hailstorm. (2) In a multicell hailstorm, the high-altitude convergence and low-level divergence of the attenuating cell promote the formation of hail embryos in developing cell. (3) Before landfall of hail for a single-cell hailstorm, the number of low-density graupel particles is almost unchanged. Due to the increase of aggregates, the rate of consumption of supercooled water particles is accelerated, resulting in a decrease in supercooled water particles. Moreover, some high-density graupel particles fall to the ground, eventually leading to a decrease in the number of high-density graupel particles, the number of distance pools decreases by 10 per min (pool is the number of pools of aqueous particles in the particle recognition result). During hailfall, high-density graupel particles attach to supercooled water particles and then grow to form hail, resulting in a decrease in high-density graupel particles and a 12.1 reduction in the number of distance pools per min. Under the “Bergeron process” (Namely Wegener-Bergeron-Findeisen process, referred to as WBF)and the adhesion of the aggregation, the number of low-density graupel particles rapidly increases, with a rate of increse by 36 pools per min. After hailfall, low-density graupel particles fall, and the number rapidly decreases, with a rate of reduction by 36.6 pools per min. During the descent process, low-density graupel particles that are attached to supercooled water, aggregates, etc., are converted into high-density graupel particles, resulting in the total amount of high-density graupel particles is almost unchanged, and the number of distance libraries increased per min is 2. (4) Multicell hailstorms are similar to single-cell hailstorms before the fall of hail, except that the development speed, number of hail embryos, and echo intensity of the single-cell hailstorm are higher compared with that of the single-cell hailstorm under the promotion of dissipating cells. During hailfall, low-density graupel particles attach to supercooled water droplets and then form into hail during the falling process, resulting in a rapid decrease in the number of low-density graupel particles, the number of distance pools reduced per min is 62.6. On the other hand, The number of high-density graupel particles increase 16.5 distance pools per min. The time from mature phase to hailfall in a multicell hailstorm is about 15 min longer than a single-cell hailstorm. The situation are similar for both processes after the hailfall. (5) Based on the analysis of the hailstorm mechanism in Weining area, the conceptual models of single-cell hailstorm and multicell hailstorm were established, respectively. This paper studies the evolution characteristics of hail embryos in each process of two typical hailstorms and obtains preliminary results, which has high application value for hailstorm early warning, prediction, and artificial hail suppression.
Key words:Particle recognition/
X-band dual polarization radar/
Microphysics/
Hail embryo
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