1988年9—11月西太平洋海区大气电场特征分析

本文利用西太平洋海区平均电场资料分析晴天和雷暴天气下地面电场特征。分析指出:雷暴下海面电场多正极性。极性通常与云顶温度有关,弱雷暴的云下部带正电荷。海洋雷暴闪电频数很低,且正闪多于负闪。分析又指出:晴天海面电场的脉动变化和近海面湍流活动有很好的对应关系,利用电场峰值宽度和间隔来估算湍流尺度和间隔距离,和湍流活动的实测结果有较好的一致性。

CHARACTERISTICS OF ATMOSPHERIC ELECTRIC FIELD AT THE WEST PACIFIC REGION IN Sep.-Nov., 1988

In this paper, based on the atmospheric electric field data collected at the West Pacific oceanic region, we analysed the characteristics of electric field near the sea surface in fair weather and thunderstorm conditions. It is shown that electric field is positive beneath thunderstorms in most cases: The electric polarity is related to the temperature of cloud top. Positive charges often exist in the lower part of clouds for weaker thunderstorms. Lightning flash rate is low for oceanic thunderstorm, and the number of Lightning flashes recorded by field mill when electric field is positive is larger than that of negative. It is also shown that the fluctuation of electric field is associated with the turbulent motion near the sea surface in fair weather. From the magnitudes of the half width and intervals between peaks of electric field we estimated the scale and interval distance of turbulence, which are in accordance with measurements of turbulent field by other workers.