# Rainfall units conversion from depth to rate/intensity

Given 6-hour rainfal data with units in meters(m), how can one convert the 6-hourly rainfall depth in meters(m) to 1-hourly rainfall intensity or rate in kg/m^2/s?

Below is a sample data value to convert.

rainfall depth (m)= 0.0014061


This is what I have tried but not sure it is correct:

To convert the 6h value to the hourly rate, I applied a multiplicative factor:

factor=0.046296296 kg/m2/s


based on the reasoning that the equivalent to:

m (in 6 hours) to mm/s = 1000/21600 (i.e. 0.0462963)


How do I use the multiplicative factor (0.046296296 kg/m2/s) to convert 6-hour rainfall depth to hourly?

Maybe I am thinking too much here.

Any thoughts?

Thank you.

• i do not understand your question.rainfall is measured in mm per hour this is the amount of water needed to cover the ground one millimeter deep. Jul 8 '20 at 17:02
• @trondhansen in this case rainfall is issued at 6-hour resolution and in meters(m). How can I convert the rainfall depth to hourly rate in kg/m2/s? Jul 8 '20 at 17:59
• fao.org/3/r4082e/r4082e05.htm Jul 8 '20 at 21:27
• As others hint at, it's worth noting that doing this calculation is at best like using the average speed from a roadtrip to estimate speed at any point (your calc is weak but potentially slightly representative for estimating longterm stratiform precipitation)... and quite possibly more like using a 6 hour average speed for Usain Bolt to estimate his sprint speed (i.e. situations dealing with stronger convective precipitation). The whole idea with precision (or sci not) is you don't try to get things from data of greater precision than you have. Really only a 6 hr rate makes useful sense. Jul 12 '20 at 23:42