negative water table depth (ZWT) with opt_run=5

[xiao.zh]

Hi all,
I ran a simulation with opt_run = 5 and obtained negative values for water table depth (ZWT), see Fig below(first output, simulation starts at 2013-01-01_00:00:00). ZWT in wrfinput is zero.

As I understand it, ZWT is defined as positive downward.

When using opt_run = 1, ZWT remains positive in my simulation.

I’m wondering whether the negative ZWT values with opt_run = 5 are correct?

 

[xiao.zh]

ZWT is negative with opt_run=5.
I found it in "THE COMMUNITY NOAH-MP LAND SURFACE MODELING SYSTEM TECHNICAL DESCRIPTION VERSION 5.0.pdf".
Page 177 said: