circulation means

• 传播手段

circulation means的用法和样例：

例句

1. Influences of solar flare bursts and partical precipitation on the lower ionosphere have been observed by means of VLF propagation effects at Zhongshan Station in Antarctica.
   在南极中山站利用甚低频传播手段观测太阳耀斑爆发及极区粒子沉降对低电离层的影响。