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Tue 26 Jan 2010 - 2:12 pm UTC
How many raindrops are there in a storm, thunderstorm, or best of all, a hurricane?
The particular duration, location, size, wind speed, do not matter -- I can use a number for any particular kind of storm -- as long as the answer specifies these qualities.
For example: for a 10 minute thunderstorm of radius one mile in the midwest, it was calculated that there were 10 million raindrops.
Should have some academic or serious citation, rather than someone estimating in a blog (unless said estimate involves serious consideration of relevant academic works).
Wed 27 Jan 2010 - 2:03 am UTC
The USA today weather resource page gives an estimated number of raindrops for an average thunderstorm as "around 1,620 trillion."
In arriving at this number they used some simple calculations and relied on some basic assumptions, based in part on information from the National Severe Storms Laboratory. Links for both are below.
Your question is similar to one asked a few years ago on Google Answers, which was how many raindrops would occupy 1 cubic foot during a thunderstorm as opposed to a light rain.
Using the answer generated there, i.e."412,700,000 little drops," you can figure the total drops for a given column in a storm. Say a storm was 15 miles wide as in the USA Today example, and 5 miles high (thunderstorms can actually reach up into the stratosphere as much as 8 miles high). The total volume would be approximately 390,180,049,332,480 cu. ft. Times 412,700,000 drops per cu. ft. that would equal 1.61027306 × 10^23 raindrops in the storm.
Now math is not my strong suit, so you might want to recheck these numbers. I used an online caclulator to do the figuring. Here's the one I used to figure the volume in case you might like to have it too: http://www.referencedesigner.com/calc/cal_07.php
For the total drops I just used Google calculator to multiply the total cubic feet by the number of drops in one cubic foot. You type the formula into the search box, click "Search" and it figures it for you.
If you would like to do some other calculations on your own, there are several different formulas given in a "WeatherBug" high school math lesson that you might find useful. Basically it says that the number of raindrops in a given storm can be estimated by dividing the total volume of a given column of accumulated water by the volume of a single rain drop.
Since there is so much variability in both size of storms and size of raindrops, the lesson makes some assumptions such as that rainfall is occurring over a flat surface and is uniform throughout. (Note that if your version of Word doesn't have the right version of Equation Editor, the equations in the doc may show up as either empty boxes or as an error message. To see the equations, right click on the box, select "Equation Object" and "Open.")
http://weather.weatherbug.com/weatherbugachieve/lp/connections_sept06/Learning_about_flooding.doc (Scroll down to Activity 2)
I hope this information is what you were looking for. If not or you need additional assistance please Request a Clarification.
This question is actually quite complex as you likely already know. The number of raindrops in a given storm varies considerably, depending on a number of factors including the size of the drops, their density, uniformity of distribution, and velocity of fall. In case you'd like to explore the topic further, I've included a few links to some other resources that might prove interesting.
"For Hurricanes, Storms, Raindrop Size Makes All the Difference"
"The Concept of “Normalized” Distribution to Describe Raindrop Spectra: A Tool for Cloud Physics and Cloud Remote Sensing"
"... Normalizing raindrop spectra is the only way to identify the shape of the distribution."
"SEA-SALT NUCLEI STUDIES: ATMOSPHERIC SALT PARTICLES AND RAINDROPS, AND REMARKS ON SEA SALT IN A TROPICAL STORM"
"...for rains of a given intensity, there is a definite distribution curve of number of raindrops of a particular range of diameter."
NATIONAL SEVERE STORMS LABORATORY POLARIMETRIC RADAR RESEARCH
Scroll down to the question: "Can you give a simple example of an improvement offered by polarimetric radar?"
Physics Forum: discussion on "how many drops are in 1 inch of rain on a 1 inch dia tube?"
Profiler Retrieved Raindrop Size Distributions
4.0 Jostt-Waldvogel Disdrometer
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