摘要
利用中尺度数值模式(TJ-WRF)模拟资料及天津加密自动气象站资料等,选取几个典型天气过程(城区附近局地强雷暴天气过程、受海风影响明显的无天气过程)个例,分析研究天津城市热岛环流与海风环流的空间结构特征及相互作用;重点对城市热岛环流与海风环流相互作用触发局地强雷暴的机制进行分析。结果表明:城市热岛环流的伸展高度基本在800 hPa附近、空间范围约为20 km、环流内有弱的辐合上升;海风环流的伸展高度在800~750 hPa、空间范围40~60 km,海风环流前沿海风锋的伸展高度为950~900 hPa,垂直上升速度平均为0.2 m·s^(-1),略强于城市热岛环流。海风环流对城市热岛环流有明显消弱作用,城市热岛环流对海风环流有一定的阻挡作用,其阻挡的程度与城市热岛环流强度有关。随海风环流向内陆推进,海风环流与城市热岛环流相遇出现叠加,叠加后的辐合上升运动明显加强,最大上升速度可达0.6 m·s^(-1),并在不稳定天气形势条件下能触发局地强雷暴天气的出现。
Using the mesoscale TJ-WRF model data and encryption automatic weather station（AWS） data,etc.,we analyze the distribution characteristics of Tianjin urban heat island circulation and sea breeze circulation as well as the interaction of them.Through several typical weather cases（Local strong thunderstorms seen in urban areas and the weather without any processes affected by the sea breeze）,the trigger mechanism of the interaction between urban heat island circulation and sea breeze circulation for local thunderstorms is analyzed.The results show that the extended height of urban heat island circulation is near800 hPa,spatial extention is about 20 km,and the upward motion is obvious.The extended height of sea breeze circulation is near 800—750 hPa and spatial extention is about 40 — 60 km.The stretch height of the sea breeze front is about 950 — 900 hPa in the forefront of the sea breeze circulation,and the upward speed is 0.2 m·s^-1 on average,slightly stronger than the heat island circulation.The sea breeze can weaken the urban heat island effect while the urban heat island can block the sea breeze circulation.With the sea breeze circulation pushed near to the urban,the sea breeze circulation and the urban heat island circulation encounter,then the two circulations get superimposed and the upward motion is significantly strengthened,causing the maximum upward speed to go up to 0.6 m·s^-1.Under the favorable weather conditions the local severe thunderstorms can be triggered.
出处
《气象》
CSCD
北大核心
2015年第12期1447-1455,共9页
Meteorological Monthly
基金
中国气象局预报员专项(CMAYBY2014-003)
天津市科委自然科学基金项目(14JCYBJC21600)共同资助
关键词
城市热岛环流
海风环流
相互作用
中尺度数值模式
urban heat island circulation
sea breeze circulation
interaction
mesoscale TJ-WRF model
