联合使用新一代多普勒雷达三维体扫资料和静止气象卫星资料,分析了京津冀地区一次中-β尺度对流风暴云砧结构的三维演变特征。以15 dBZ雷达回波为阈值,提出了分析云砧演变过程的三个有效指标:风暴的"高中层面积差"、"高低层面积差"和"低层面积"。在此基础上,将云砧结构的演变过程划分成四个阶段:云砧结构形成期、云砧结构维持期、云砧结构崩溃期和风暴消亡期。雷达和静止卫星观测到的云砧演变特征具有明显的相关性:雷达最大组合反射率因子与IR1通道最低TBB呈显著的相关性,均在云砧结构的形成期或维持期达到极值;极值后,强冷云区(TBB小于-45℃)面积在15 min内就达到峰值,而弱冷云区面积在大约1 h后的云砧崩溃期才达到峰值。
This paper analyzes the evolution of anvil clouds generated by meso-β-scale convective storms using Doppler weather radar data and geostationary satellite data of a case in the north of China on 24 June 2006.Three radar-observed characteristics of the storms at the 15 dBZ threshold,the "area difference between high and low levels","area difference between high and middle levels",and "area at low levels",are identified as good indicators of anvil clouds evolution.Based on these indicators,the life cycle of anvil clouds is divided into four stages: growing stage,maintaining stage,collapsing stage and decaying stage.The characteristics of anvil evolution observed by radar and satellite are significantly correlated.There is significant correlation between the maximum composite reflectivity and the minimum TBB at 10.3 ~ 11.3 μm,and the extremes appear in the growing or maintaining stage of the anvils.Then,the area of anvil clouds at a lower temperature threshold(-45 ℃) reaches the peak in 15 minutes,but the delay of the maximum anvil clouds area at higher temperature thresholds takes about 1 hour.