Concerning the Water Balance in WRF-Hydro

[ZiYang]

Hi everyone,

I have now run WRF-Hydro and obtained results. I wish to examine the water balance, using the formula: precipitation - surface runoff - groundwater runoff - change in soil water - evapotranspiration. My evapotranspiration was calculated using ECAN+EDIR+ETRAN, yet the result I obtained reached approximately -100. I would like to understand why this occurred. Is there an issue with my calculation formula? If there is an issue, I would like to understand how the water balance should be calculated within WRF-Hydro.

Thank you very much for your time, and I truly appreciate the valuable support.

[aubrey]

Hi Zi:

Are you saying your total ET from the LDASOUT files is -100? Which values of the 3 you are combining are negative? EDIR and ECAN can be slightly negative under certain circumstances (e.g., when there is dew being deposited), but ETRAN should never be negative. Make sure you are not including nodata values (e.g., over water cells) in your calculations.

Let us know how it goes.

Thanks!

Aubrey