60秒科学:The Rain's Maintained Speed Strain Is Now Explained

The Rain's Maintained Speed Strain Is Now Explained

A study in the journal Geophysical Research Letters finds that some raindrops are falling faster than they "should" be, which means meteorologists may be overestimating¹ the total amount of rainfall. Steve Mirsky reports.

Could it be that our understanding of rain was all wet? A new study says that some drops of rain are falling faster than they should be. Which ultimately means that it may be raining less than we think.

It's been assumed that large raindrops fall faster than smaller ones. A big drop’s size and heft give it a faster terminal velocity². Because it overcomes air resistance better than a small drop. But now researchers have found small raindrops falling faster than some bigger drops, and faster than what their terminal velocity should be. The finding appears in the journal Geophysical Research Letters.

Researchers used sophisticated optical equipment to study about 64,000 individual raindrops, and found the expeditious³ outliers. Which came in clusters. These superfast droplets⁴ probably come from the breakup of fast-moving large drops. Standard techniques to measure rain assume that fast drops are larger, and therefore overestimate⁵ the total precipitation. The scientists note that a third of the economy is influenced by weather forecasting, so even a small improvement in our understanding of rain would be more than a drop in the bucket.

—Steve Mirsky

 

1 overestimating   

对（数量）估计过高，对…作过高的评价( overestimate的现在分词 )

参考例句：

• I think you're overestimating his abilities. 我看你对他的能力评价过高。
• With hindsight, he was overestimating their desire for peace. 事后看来，他高估了他们对和平的渴望。

2 velocity   

n.速度，速率

参考例句：

• Einstein's theory links energy with mass and velocity of light.爱因斯坦的理论把能量同质量和光速联系起来。
• The velocity of light is about 300000 kilometres per second.光速约为每秒300000公里。

3 expeditious   

adj.迅速的，敏捷的

参考例句：

• They are almost as expeditious and effectual as Aladdin's lamp.他们几乎像如意神灯那么迅速有效。
• It is more convenien,expeditious and economical than telephone or telegram.它比电话或电报更方便、迅速和经济。

4 droplets   

n.小滴( droplet的名词复数 )

参考例句：

• Droplets of sweat were welling up on his forehead. 他额头上冒出了滴滴汗珠。 来自辞典例句
• In constrast, exhaled smoke contains relatively large water droplets and appears white. 相反，从人嘴里呼出的烟则包含相当大的水滴，所以呈白色。 来自辞典例句

5 overestimate   

v.估计过高，过高评价

参考例句：

• Don't overestimate seriousness of the problem.别把问题看重了。
• We overestimate our influence and our nuisance value.我们过高地估计了自己的影响力和破坏作用。