PISM, A Parallel Ice Sheet Model  stable v2.0.5 committed by Constantine Khrulev on 2022-10-14 09:56:26 -0800

## ◆ till_friction_angle() [2/2]

 void pism::MohrCoulombYieldStress::till_friction_angle ( const IceModelVec2S & bed_topography, IceModelVec2S & result )
private

Computes the till friction angle phi as a piecewise linear function of bed elevation, according to user options.

Computes the till friction angle $$\phi(x,y)$$ at a location as the following increasing, piecewise-linear function of the bed elevation $$b(x,y)$$. Let

$M = (\phi_{\text{max}} - \phi_{\text{min}}) / (b_{\text{max}} - b_{\text{min}})$

be the slope of the nontrivial part. Then

$\phi(x,y) = \begin{cases} \phi_{\text{min}}, & b(x,y) \le b_{\text{min}}, \\ \phi_{\text{min}} + (b(x,y) - b_{\text{min}}) \,M, & b_{\text{min}} < b(x,y) < b_{\text{max}}, \\ \phi_{\text{max}}, & b_{\text{max}} \le b(x,y), \end{cases}$

where $$\phi_{\text{min}}=$$phi_min, $$\phi_{\text{max}}=$$phi_max, $$b_{\text{min}}=$$topg_min, $$b_{\text{max}}=$$topg_max.

The default values are vaguely suitable for Antarctica. See src/pism_config.cdl.

Definition at line 349 of file MohrCoulombYieldStress.cc.

Referenced by bootstrap_impl().