# Doubt about rainc and rainnc variables

#### mantovanijr

##### New member
Hi everyone.

My doubt is regarding to rainc and rainnc variables. Considering that I had hourly outputs and I want to plot, for instance, hourly precipitation need I subtract previous hour from the current to obtain the hourly precipitation or are this variables only the computed precipitation at that hour (i.e., the model do not accumulate through the running)?

In other words:

Is, considering hourly outputs and t as time, hourly_precipitation_t = (rainc[t,:,:]+rainnc[t,:,:]) or hourly_precipitation_t= ((rainc[t,:,:]+rainnc[t,:,:])-(rainc[t-1,:,:]+rainnc[t-1,:,:])) ?

Thank you.

rainc and rainnc are accumulated precipitation since the initial model time. Therefore, your method to obtain hourly precipitation is correct.

rainc and rainnc are accumulated precipitation since the initial model time. Therefore, your method to obtain hourly precipitation is correct.
Your answer is not so clear. I sent two formulas in bold, which is the correct? Is the First or second one? Accordingly to your answers the second formula, apparently, would be the correct.

You are right that the 2nd formula is correct.

@mantovanijr @Ming Chen

I would like to add one more thing. There is another variable in WRF that may or may not be present in your output file.

RAINSH (the amount of shallow convective precipitation)

so the hourly would be this

Code:
``hourly_precipitation_t = (rainc[t,:,:] + rainnc[t,:,:] + rainsh[t,:,:]) - (rainc[t-1,:,:] + rainnc[t-1,:,:] + rainsh[t-1,:,:])``

@mantovanijr @Ming Chen

I would like to add one more thing. There is another variable in WRF that may or may not be present in your output file.

RAINSH (the amount of shallow convective precipitation)

so the hourly would be this

Code:
``hourly_precipitation_t = (rainc[t,:,:] + rainnc[t,:,:] + rainsh[t,:,:]) - (rainc[t-1,:,:] + rainnc[t-1,:,:] + rainsh[t-1,:,:])``