ContentStress Class Reference

A simple water content based stress model based on Feddes (1978) More...

Inheritance diagram for ContentStress:

Collaboration diagram for ContentStress:

Detailed Description

A simple water content based stress model based on Feddes (1978)

stress a is piecewise linear function based on water content

• if \(\theta>\theta_d \rightarrow ET = ET_{pot}\)
• if \(\theta_d>\theta > \theta_{wilt} \rightarrow ET = \frac{\theta_d - \theta}{\theta_d - \theta_{wilt}} ET_{pot}\)
• if \(\theta_{wilt}>\theta \rightarrow ET = 0.0 \)

The parameters \(\theta_{d,w}\) can be omitted (or set to a negative value) to use default values derived from the layer properties. The critical water content (where stress starts) is then defined (conf. Feddes 1978) as the center between field capacity ( \(\theta_{fc}\)) and the wilting point ( \(\theta_{wp}\)).

• \(\theta_w = \theta(pF=4.2)\): Water content at pF=4.2
• \(\theta_d = 1/2 (\theta(pF=1.8) + \theta(pF=4.2))\)

Public Member Functions
	ContentStress (real theta_d=-1, real theta_w=-1)
	Creates a new ContentStress for critical water content theta_d in vol Water/vol Soil and wilting point theta_w.
cmf::upslope::ET::ContentStress *	copy () const
	Creates a new copy of this wetness.
virtual real	Tact (const cmf::upslope::SoilLayer *soillayer, real Tpot) const
	Calculates the water stress for a layer.

Member Function Documentation

Tact()

virtual real Tact ( const cmf::upslope::SoilLayer * soillayer, real Tpot ) const

virtual

Calculates the water stress for a layer.

Parameters

soillayer	The cmf::upslope::SoilLayer this stress function belongs to
Tpot	Potential Transpiration in mm/day (for the full profile)

Returns

Actual flux from layer in m3/day

Implements RootUptakeStressFunction.