摘要:利用探空火箭、新一代天气雷达和气象探测资料对2015年7月17日延安宝塔区冰雹云进行了综合探测，结果表明：（1）当日08:00（北京时，下同）500 hPa河套低涡分裂东移，有较强冷平流且移动速度较快，地面14:00升温明显造成了这次降雹。（2）偏后位置的冰雹云内部温、湿条件以及对流指数（Tg）、整层比湿积分（IQ）、总指数（TT）均小于外部的自然大气；层结稳定度指数（K）、抬升指数（LI）、沙氏指数（SI）冰雹云内部比外部自然大气偏小；热力参数风暴强度指数（SSI）冰雹云内部低于外部自然大气；冰雹云内部能量参数（CAPE）明显低于自然大气；冰雹云内部0°C层高度低于冰雹云外部自然大气。（3）火箭探测的位置偏冰雹云后部，冰雹云由低层到高层风向呈逆时针变化，探空仪摆动明显，?20°C温度层偏高，气流较强，整层偏下沉气流。（4）冰雹云0°C附近，在温度区间?1.8～5.0°C、厚度1.0 km范围内有最大湿度区，湿度达80%以上，最大湿度87.1%，为冰雹的形成提供了水汽条件。（5）紧贴0°C下正温区，有最大水平风速为19 m s?1急流，厚度为0.022 km。在温度区间?4.8～5.0°C、厚度1.6 km范围内维持13 m s?1以上水平风速，为冰雹的形成提供了动力场条件。（6）在温度区间?8.7～?9.2°C、厚度0.2 km，有小于或等于2 m s?1弱风区；弱风区下方，在温度区间?4.6～?8.8°C、厚度0.889 km有上升气流，平均上升速度1.79 m s?1，最大上升速度4 m s?1，这种配置为冰雹的生长提供了环境场。
关键词:冰雹云/
内部结构/
气象要素/
演变特征
Abstract:Using rocket sounding data, a new generation of weather radar data and meteorological data is utilized to comprehensively analyze the hail cloud in Baota District, Yan'an County, on July 17, 2015. The results show the following aspects. (1) At 0800 BT (Beijing time), low vortex in the Hetao region split eastward, with a strong cold advection; the fast movement and a rising of surface temperature at 1400 BT caused this hail. (2) The hailstorm conditions inside the backward position, such as temperature and humidity, convection index (Tg), whole layer special humidity integral index (IQ), and total totals index (TT), are lower than those in the external natural atmosphere. The stratification stability index (K), lifted index (LI), and Showalter index (SI) show that hail clouds inside are smaller than those outside. The storm severity index (SSI) of the hail cloud, a thermal parameter, is lower than that in the natural atmosphere. The internal energy parameter, i.e., convective available potential energy (CAPE) is considerably lower than those in the natural atmosphere. The height of the 0°C layer inside the hail cloud is lower than the natural atmosphere outside the hail cloud. (3) Location of the rocket detection is opposite to the back of the hail cloud. The wind direction changes counterclockwise from downward to upward in the hail cloud.At the ?20°C high-temperature layer, air flow is higher and stronger, and the whole layer has partial sinking airflow. (4) The temperature range that is near the 0°C layer in hail cloud is ?1.8°C–5.0°C. The maximum humidity area is within the depth of 1.0 km, where humidity is over 80% and the maximum humidity is 87.1%. These provide water vapor conditions for hail formation. (5) There is a maximum horizontal wind speed of 19 m s?1 rapid flow and a thickness of 0.022 km close to the lower layer of 0°C. The layer also maintains a horizontal wind speed of 13 m s?1 or above in the temperature range of ?4.8°C–5.0°C and a thickness within 1.6 km. These provide a dynamic field condition for hail formation. (6) There is a weak wind zone of ≤ 2 m s?1 in areas where the temperature range is ?8.7°C–9.2°C and the thickness is within 0.2 km. Below the weak wind zone, where the temperature range is ?4.6°C–8.8°C and the thickness is within 0.889 km, it is the updraft. Here, the average rising speed is 1.79 m s-1, and the maximum rising speed is 4 m s?1. This configuration provides an environmental field for the growth of hail.
Key words:Hail cloud/
Internal structure/
Meteorological elements/
Evolution characteristics
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