南海北部强冷空气过程的风速阵性特征

发布时间：2018-03-15 08:05

本文选题：海洋气象学　切入点：南海北部　出处：《应用海洋学学报》2017年01期 　论文类型：期刊论文

【摘要】：通过对南海北部塔基单站单层强冷空气入侵过程的三维风速记录进行小波分析,研究南海北部一次强冷空气过程,风水平速度和垂向速度的三维相干特征,得到相干结构的生成周期及演变特征.结果表明:在强冷空气入侵过程中,主要阵风扰动相干结构有两类,一是持续时间较短(约1min),发生周期2~10 min之间的不连续相干结构;二是持续时间与发生周期几乎相等的连续相干结构,其持续时间和周期在1~13 min之间.连续相干结构要比非连续相干结构能量大、分布广、周期变化多.后者在冷锋南侵强风对流天气影响下,扰动作用大,混合加剧,相干结构充分发展,表现出连续的相干结构特征.相干结构的生成及能量分布与阵风风速有密切的关系,阵风风速越大相干结构越活跃.冷锋南侵时,阵风扰动与垂向通量传输呈同向锁相关系,是下沉气流传输的主要扰动因素.风间歇期(小风),有上升气流,主要是西北风动量的脉动下传,感热上传,随着强冷空气的到来,风向转为强冷北风阵风,下沉气流加剧.
[Abstract]:Based on wavelet analysis of wind velocity records of a single station single layer strong cold air intrusion in the northern part of the South China Sea, the three dimensional coherence characteristics of a strong cold air process, wind horizontal velocity and vertical velocity in the north of the South China Sea are studied. The generation period and evolution characteristics of coherent structures are obtained. The results show that there are two main types of coherent structures in strong cold air intrusion. One is the discontinuous coherent structure with a short duration (about 1 min) and a period of 2 ~ 10 min. The second is the continuous coherent structure with almost equal duration and generation period, whose duration and period are between 1 ~ 13 min. The energy of continuous coherent structure is larger than that of non-continuous coherent structure, and the distribution of the structure is wider than that of non-continuous coherent structure. Under the influence of the cold front and strong wind convection, the latter has a large disturbance, the mixing intensifies, and the coherent structure is fully developed. The formation and energy distribution of coherent structures are closely related to the gust wind speed. The larger the gust wind speed, the more active the coherent structure is. When the cold front invades southward, the gust disturbance and vertical flux transfer are in the same phase locked relation. It is the main disturbance factor of downdraft flow transmission. (small wind, there is updraft, mainly pulsation of northwest wind momentum, inductive heat transfer, with the arrival of strong cold air, the wind direction turns to strong cold north wind gusts, and the sinking airflow intensifies.
【作者单位】：国家海洋局南海信息中心;国家海洋局第三海洋研究所;中国气象局广州热带海洋气象研究所;
【基金】：国家“973”资助项目(2015CB452801) 国家自然科学基金资助项目(41275025)
【分类号】：P732

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