摘要
利用美国国家环境预报中心(NCEP/NCAR)的再分析资料、广东省遥测站资料及MICAPS资料,通过合成分析、对比分析等方法,对一次春季冷空气伴随的海上大风天气过程分析,研究了冷空气过程中地面变压和低层温度平流的变化特征以及与地面风场之间的关系。结果发现:本次海上大风天气过程具有春季强风的2个明显特点:1、"风头(起风时)大、风尾(结束时)小";2、起风突然、阵风大。具有明显的日变化,夜间比白天大。影响系统主要是:200 hPa西风槽、500 hPa南支西风槽、850 hPa切变线、地面冷空气和冷锋系统。温度平流通过变压场作用于地面风场,冷空气伴随的冷平流增强了地面变压场以及变压梯度,进而等压线密集,地面风速加大。
With the reanalysis from NCEP/NCAR, remote-sensing data from Guangdong province and MICAPS data and the methods of composite analysis and contrastive analysis, this study analyzes a process of marine high wind associated with a springtime cold-air incident for the surface alloharic field and low-level temperature advection during the cold air process and their relationships with the surface wind field. As shown in the results, this marine high wind has two striking points that are characteristic of springtime gales ; first, the wind is strong initially hut weak towards the end and second, the wind erupts abruptly and the gust is powerful. The process is also marked with well-defined diurnal variation with higher speed at night than in the daytime. Systems responsible for this marine high wind are mainly a 200 hPa westerly trough, the southern branch of a 500 hPa westerly trough, an 850 hPa shear, surface cold air and a cold front. Via the allobaric field, the temperature advection acts on the surface wind field. A cold advection associated with the cold air strengthens the allobaric field and gradient at the surface to make the isobaric line denser and the surface wind speed larger.
出处
《广东气象》
2013年第1期19-23,共5页
Guangdong Meteorology
基金
广东省科技计划项目"广东省突发灾害性天气应急技术研究中心"(2011A032100006)
气象关键技术集成与应用重点项目"精细化预报交互订正系统GIFT"(CMAGJ2013M35)共同资助
关键词
天气学
海上大风
合成分析
冷空气
温度平流
synoptics
marine high wind
composite analysis
cold air
temperature advection
