<p>I want to calculate the precipitation rate (mm/hr) from the WRF model output. After searching online, I learned from this conversation (<a href="https://earthscience.stackexchange.com/questions/7746/calculate-precipitation-from-wrf-model-output">Calculate precipitation from WRF model output</a>) that I need to just add 'RAINC' and 'RAINNC' to get the precipitation (i.e., RAINC+RAINNC). Now, I did this to compute the precipitation. However, after checking the hourly progression of these two variables, i.e., 'RAINC' and 'RAINNC', I realized that the WRF model is not giving the precipitation value for every hour; rather, it is adding every hour precipitation value. For example, whatever precipitation values are there in the 1st hour, in the 2nd hour, it is also considering the value of the 1st hour as well as the the value for the 2nd hour, and so on. But, I want to extract the exact precipitation value for every hour so that I can see the hourly variation of precipitation rate.
So, can anyone please guide me on how to calculate the precipitation rate (mm/hr) from these WRF model output variables? Any help will be really appreciated.</p>
<p>With regards,</p>
<p>Ankan</p>

CC BY-SA 4.0
2024-09-18T08:12:38.477Z
Not my field, but can't you just output wrfout at hourly intervals? Then the difference between two consecutive files is the hourly rate.
Jean-Marie Prival
CC BY-SA 4.0
2024-09-18T13:53:08.250Z
Thank you for the response.
Ankan
CC BY-SA 4.0
2024-09-20T10:09:22.430Z
@Ankan hello, does the answer of Ming Chen fits to your purpose?  https://forum.mmm.ucar.edu/threads/how-to-calculate-precipitation-rate-mm-hr-from-wrf-model-output-variable.19155/
Dimitris Tsiaousidis
<wrf><wrf-chem>
How to calculate precipitation rate (mm/hr) from WRF model output variable?
Ankan
# How to calculate precipitation rate (mm/hr) from WRF model output variable?

(Asked by: username_0 on 2024-09-18)

I want to calculate the precipitation rate (mm/hr) from the WRF model output. After searching online, I learned from this conversation ([Calculate precipitation from WRF model output](https://earthscience.stackexchange.com/questions/7746/calculate-precipitation-from-wrf-model-output)) that I need to just add 'RAINC' and 'RAINNC' to get the precipitation (i.e., RAINC+RAINNC). Now, I did this to compute the precipitation. However, after checking the hourly progression of these two variables, i.e., 'RAINC' and 'RAINNC', I realized that the WRF model is not giving the precipitation value for every hour; rather, it is adding every hour precipitation value. For example, whatever precipitation values are there in the 1st hour, in the 2nd hour, it is also considering the value of the 1st hour as well as the the value for the 2nd hour, and so on. But, I want to extract the exact precipitation value for every hour so that I can see the hourly variation of precipitation rate.
So, can anyone please guide me on how to calculate the precipitation rate (mm/hr) from these WRF model output variables? Any help will be really appreciated.

With regards,

username_0

**Tags:** wrf, wrf-chem

> **Comments:**
> **username_1**: Not my field, but can't you just output wrfout at hourly intervals? Then the difference between two consecutive files is the hourly rate.  
> **username_0**: Thank you for the response.  
> **username_2**: @username_0 hello, does the answer of Ming Chen fits to your purpose?  https://forum.mmm.ucar.edu/threads/how-to-calculate-precipitation-rate-mm-hr-from-wrf-model-output-variable.19155/  

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## 0 answers

