This project is able to calculate the mean first passage time (MFPT), which in this project represents the average time for the drop of relative soil moisture from a high level to a low level.
x1 is high level of relative soil moisture, x2 is the lower level. w0 is water storage capacity in the rooting zone, λ is rainfall rate, α is average rainfall depth, and Emax is potential evapotranspiration.
MFPT for relative soil moisture to drop from x1 to x2.
x is the relative soil moisture, gma=w0/α, pi2=λ/eta.
The probability density function (PDF) of relative soil moisture .
x is the relative soil moisture, gma=w0/α, pi2=λ/eta.
The cumulative distribution function (CDF) of relative soil moisture.