冷涡背景下一次强对流过程的卫星水汽图像特征  

Characteristics of a cold vortex related severe convection on satellite water vapor imagery

作　　者：吴志彦 闵锦忠[2] 赵海军 

机构地区：[1]威海市气象局,山东威海264200 [2]南京信息工程大学,江苏南京210044 [3]临沂市气象局,山东临沂276004

出　　处：《海洋气象学报》2017年第3期54-61,共8页Journal of Marine Meteorology

基　　金：国家自然科学基金项目(41175092);山东省气象局青年科研基金项目(2016SDQN17);威海市科学技术发展计划项目(2014GNS014)

摘　　要：将卫星水汽图像与高层动力场进行叠合分析,可为强对流天气监测预报提供有价值的信息。将卫星水汽图像和大气动力场相结合,对山东省一次冷涡背景下连续强对流过程的环境特征进行分析。结果表明,冷涡云系具有非对称结构特征;冷涡东南侧的暖湿对流与涡后动力干带入侵时爆发的暗区新生对流,这两个阶段的热、动力不稳定增长机制有所不同。与高位涡、急流相伴的水汽暗带是对流层上部的动力活跃区。当涡后具有高位涡特征的动力干带入侵时,高层动力活跃区叠加于低层暖湿平流区上空,促使对流爆发。卫星水汽图像体现了冷涡发展不同阶段高空动力强迫的差异。水汽图像上动力干带色调变暗,干湿边界锐化的特征,与高层位涡和高空急流增强有关。通过卫星水汽图像上连续时次的干湿对比,可以跟踪识别这些高层特征,进而判断高层动力特征的演变,为深厚湿对流环境条件的诊断提供依据。Water vapor imageries superimposed with upper-level dynamical fields can potentially provide valuable information for operational forecasting. A joint interpretation of a cold vortex related severe convection in Shandong Province is conducted by employing water vapor imagery and upper-level dynamic fields. Results reveal that the cloud system of the cold vortex exhibited asymmetric structure.Mechanism of instability growth varied between the warm and moist convection in the southeast and the convection out broke in the dynamic dry band at the rear of the vortex. As the dynamic dry band at the rear of the cold vortex overrunning the warm and moist area at the lower levels of the troposphere,deep convection was induced. Water vapor imageries closely mirror the upper-level synoptic-scale forcing during different developing stages of the cold vortex. The pronounced darkening of the dynamic dry band combined with sharpening of the dark/light boundary is associated with the strengthening of high potentialvorticity and the upper-level jet. Monitoring a sequence of water vapor imageries helps in identifying and following the upper-level dynamic forcing,and provides valuable information of upper-level dynamic fields in diagnosing deep convection environment.

关 键 词：卫星水汽图像 位涡 冷涡 强对流 

分 类 号：P405[天文地球—大气科学及气象学]