How does drizzle form?

Not everyone has ever encountered the drizzle, the wind wick. But have you ever wondered, what is drizzle? How does drizzle form? The following article will answer your questions above, please consult.

>> Why did there be drizzle in the Qing period?

Drizzle seeds are usually only about 1 millimeter in size, and are much more leisurely on the ground.

Robert McGraw and Yangang Liu, Brookhaven National Laboratory, New York (USA), said drizzles formed much faster than we thought, without needing an hour as previously assumed . Even if the density of water particles under the cloud has not reached the limit of creating rain, they are also quickly joined together, forming larger particles and falling, making us soaked.

According to scientists, while the usual raindrops have a diameter of at least 2 millimeters or more, and plunge into the ground at a rate of about 9m / sec, the drizzle is usually only about 1 millimeter, and swoops down. much more leisurely ground, about half a meter / second (more precisely, they are blown away by the currents). These two types of rain are formed in two different conditions: regular rain occurs when air flows up, causing water droplets to collide, merge and become bigger. And drizzling rain formed in quieter conditions - no air flow raised them like that.

No matter what conditions, rain drops are formed in the same way: In the first 20 minutes, moisture molecules in the air condense, forming droplets about 0.04 millimeters in diameter (also in At this time, the droplet goes through the process of creating the agglutination nucleus - the period when it reaches a certain size, from which on, the amount of water absorbed will be greater than the amount of water evaporated). From 0.04 millimeters, water droplets start falling and getting bigger, mainly due to fusion with surrounding particles.

According to a popular theory, from 0.04 millimeters in size, the droplets take another hour to reach the size of the drizzle. However, the reality is that rain clouds usually only last about half an hour. If so, does it take longer to form rain than the lifetime of the cloud? This is ridiculous.

New models by McGraw and Liu have shed light on this. They hypothesize that, in the consolidation phase (ie when the particle is greater than 0.04 millimeters), the droplets must pass a second " barrier ", similar to the agglomeration stage. Overcoming this " bureaucracy ", water droplets will bulge quickly.

Calculations show that, indeed, in the moisture content of rain-causing clouds, the second " hurdle " rate of water droplets is very fast, and the time they need to move to less drizzle sizes more than 1 hour. Therefore, drizzle may appear in very short time periods.