云的含水量及其水循环

通过分析云的含水量表明:①全球的云中含水量约为90×109t,与大气中气体状态的水汽比,不足其1%,在计算大气总含水量时可以忽略;②积雨云含水分丰富,但是计算显示它持有的水分也少于3mm。③由于云的含水量很小,而每年有1000mm的雨雪从云中降落,所以云中的水分循环很快,从成云到致雨(雪)不足2h。

Water content of cloud and its water circulation

The calculation and analysis indicte that:(1)The total water content of global cloud is nearly 90×10⁹ t,which is less than 1% comparing with the global vapor.So when calculating the amount of globe atmospheric water,the cloud water content can be ignored;(2)Cumulonimbus is abundant of water,but calculation shows that its precipitable water is less than 3 mm;and(3)There are 1 000 mm water precipitated from the cloud every year,but the precipitable water of cloud is exiguity,so water circulation is very quickly.The duration of a water element from the beginning of cloud to landing as rain is less than 2 hours.