With the continuously developmentof China's marine strategy,all kinds of fixed and mobile offshore platforms are required to carry out more effective lightning protection.It is very important to understand the horizontal radiated electric field (Er) of lightning current sources in the marine layered medium.The paper focuses on study of CG lightning flashes that can have a distinct impact on the marine facilities.The first return stroke of positive CG lightning current source (PS) and the Nucci current source (TLS) were selected to carry out comparative analysis of the propagation characteristics of horizontal radiated electric fields of two kinds of lightning current source in the stratified marine medium that is composed of air,sea water and oceanic crust.The results show as follows (1) At the heights of the sea level and above it (h ≥0 m),when the horizontal distance from the lightning current source is 0m (r---0 m),values of Er produced by two kinds of lightning current sources are positive.Values of Er produced by PS are logarithmically increased with time,while ones of TLS show as the single peak of positive skewness distributions with time.Values of Er of two lightning current sources of r ＞ 0 m are inverse phase with ones of r =0 m.(2) When h is 0～50 m and 100～500 m at r =0 m,the value of Er of PS at 10 μs after the occurrence of lightning is 3.273 3×106 ～ 1.177 1×107 v/m and 1.035 1×107 ～ 1.155 3×107 v/m,respectively;while the peak value ofEr of TLS is 9.274 7×105 ～ 2.887 8×106 and 2.688 7× 106～2.854 2× 106 v/m,respectively.(3) When r is 50～500 m at h=1 0 m,the value of Er of PS at 10 μs after the occurrence of lightning is-1.121 6× 104～7.027 9 v/m,while the peak value of Er of TLS is-2.478 4× 1 03～ 1.385 9× 10 v/m.At h=10 m and r=-1 000 m,the peak value of Er of TLS is 9.182 6 v/m.(4) At heights under the sea level (h ＜ 0 m),when r is 50～ 1 000 m,values of Er of two kinds of lightning current source are positive and the single peak of positive skewness distributions with time;the difference of Er of PS and TLS at h =-5 m and-10 m is 5～53 v/m and 2～28 v/m,respectively.%随着我国海洋战略的持续推进,海上各类固定及移动的工作平台均需进行更加有效的雷电防护.海上防雷工作中深入了解雷电电流源水平辐射电场(Er),在海洋分层介质中的传播特性则是一项十分重要的工作.本文就能够对海上设施产生较大影响的地闪进行研究,因此选取具有代表性的正地闪首次回击电流源(PS)及Nucci电流源(TLS),通过时域的方法对两种雷电电流源的水平辐射电场在由空气、海水及洋壳所组成的海洋分层介质中的传播特征进行对比分析.结果表明:(1)在海面及其以上的高度(h≥0 m),当距雷电电流源水平距离r=0m时,两种雷电电流源产生的Er均为正值;其中PS产生的Er是随时间呈对数增加,而TLS的则随时间呈单峰正偏态分布;当r＞0m时,两种雷电电流源产生的Er与r=0m时的基本呈反位相. (2)当r=0m,h介于0～ 50m及100 ～ 500 m之间,PS于雷电发生后10μs的Er值则分别介于3.273 3×106～1.177 1×107 v/m及1.035 1×107～1.155 3×107 v/m之间,而TLS的Er峰值则分别为9.274 7×105 ～ 2.887 6×106 v/m及2.688 7×106～2.854 2×106 v/m之间. (3)当h=10m,r介于50 ～ 500 m之间,PS于10μs的Er值则介于-1.1216×104～-7.027 9 v/m之间,而TLS的Er峰值则介于-2.478 4×103 ～ 1.385 9 v/m之间;当h=10m,r=1000m时,TLS的Er峰值为9.482 6 v/m.(4)在海面以下(h＜0 m),r介于50～ 1000m之间,两种雷电电流源的Er主要为正,且随时间均呈单峰正偏态分布;当h=-5m及-10m时,PS与TLS的Er值于两个深度的差分别介于5～ 53 v/m与2～28 v/m之间.
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