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I have a rainfall volume of $140$ mm, $180$ mm and $65$ mm. I have to convert this rainfall data into Cumulative rainfall with units of cubic meters.

Bobson Dugnutt
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Rohit Haritash
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    A milimeter cannot be converted into a cubic meter, because one measures volume while the other measures distance. – 5xum Sep 09 '16 at 10:28
  • I am looking at an example. They converted 105mm of monthly rainfall onto 5894.18 cu m. Any ideas? – Rohit Haritash Sep 09 '16 at 10:29
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    Well, one milimeter is equal to one liter per square meter, which is $0.001$ cubic meters per square meter, but "cubic meter per square meter" is not the same as "cubic meter". – 5xum Sep 09 '16 at 10:30
  • Rainfall indeed is measured in units of length and not volume, because what matters (and what can be reasonably measured) is the average volume of rain per unit area, and not so much the actual volume over a given region. So if you have to give the volume of rain fallen, you will need more information, such as the surface area of the region you are considering. – Joey Zou Sep 10 '16 at 00:37

1 Answers1

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When talking about rainfall measurements, the convention is $$1 \text{ mm of rainfall} = 1\; \frac{\text{L}}{\text{m$^2$}}.$$

So if you measures $140 \text{ mm}$, this means that $140\;\frac{\text{L}}{\text{m$^2$}}$ fell in that period of time.

That means that the cumulative rainfall would be $$(140+180+65) \text{ mm}=385\;\frac{\text{L}}{\text{m$^2$}}$$ in all three periods combined. Note that $1 \text{ L}=10^{-3}\text{m$^3$}.$

But you can't make a $\text{mm}$ into $\text{m$^3$}$ no matter how hard you try.

Bobson Dugnutt
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