温带气旋和梅雨锋的卫星云图特征  

Satellite Imagery Characteristics for Extratropical Cyclones and Meiyu Fronts

作　　者：许健民[1] Xu Jianmin(National Satellite Meteorological Centre, Beijing 100081)

机构地区：[1]国家卫星气象中心,北京100081

出　　处：《气象科技进展》2021年第3期14-26,共13页Advances in Meteorological Science and Technology

摘　　要：介绍温带气旋和梅雨锋的卫星云图特征。温带性气旋是来自不同方向的三支气流(暖输送带、冷输送带、干带)的汇合过程,梅雨锋气旋是气旋簇中的一系列气旋波中所处纬度最低的。在西藏高原东侧的中国东部地区,由于与特定地形、地理条件相伴的动力、热力作用,对流层上部从高原东伸的脊与它北侧的副热带急流夹得很紧,两者之间有多方向的外流;而对流层下部有极其潮湿的东西向切变线。这样的大气三度空间结构,趋向于符合对称不稳定条件,这使得密实、连续的梅雨锋云带得以稳定、持续地维持。也正是由于雨带上空被潜热加热的气流向东南扩散下沉,十天甚至半个月以后,环流形势将发生调整:或出现副热带高压加强,雨带北抬;或形势转变为经向型。经向型云带里不同区段云的密实程度有差异,这与沿云带低层气流的汇合、涡度以及云带与西太平洋热带扰动之间的相互作用有关系。This paper introduced satellite imagery appearance for extratropical cyclones and Meiyu fronts.Extratropical cyclone is consisted of three conveyor belts:warm conveyor belt,cold conveyor belt and dry slot.Meiyu frontal cyclones are the ones among series cyclones at the lowest latitudes.In Eastern China due to dynamical and thermo-dynamical processes associated with specific topographical and geographical features,in the upper troposphere,there is an anti-cyclonic ridge extending eastward from Tibetan Plateau.Between this ridge and a subtropical jet stream closely to its northern side,the upper tropospheric flows diverse towards multi directions to the eastern and southern sides.Coupled with the upper ridge in the lower troposphere,there is an shear line east-west oriented with extreme wet humidity.Such three dimensional structure of the atmosphere approaches the condition of the symmetric instability.As a result,the Meiyu frontal cloud belts become dense,continuous and long lasting.It is due to the latent heating along the rain belt in the upper troposphere,after a time period about 10—15 days,the pattern is evolved,either the rain belt moves northward,or the pattern turns into longitudinal.With longitudinal pattern,the densities of the clouds vary in different regions of the cloud belt related with the vorticity and convergence in the low level air flow and its interaction with the surrounding tropical disturbances.

关 键 词：温带气旋 梅雨锋 卫星云图 

分 类 号：P458[天文地球—大气科学及气象学]