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PISM, A Parallel Ice Sheet Model 2.2.2-d6b3a29ca committed by Constantine Khrulev on 2025-03-28
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PatersonBuddCold.cc
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19
20#include <cmath>
21
22#include "pism/rheology/PatersonBuddCold.hh"
23
24namespace pism {
25namespace rheology {
26
27PatersonBuddCold::PatersonBuddCold(const std::string &prefix,
28 const Config &config,
30 : PatersonBudd(prefix, config, ec) {
31 m_name = "Paterson-Budd (cold case)";
32}
33
34double PatersonBuddCold::tempFromSoftness(double A) const {
35 return - m_Q_cold / (m_ideal_gas_constant * (log(A) - log(m_A_cold)));
36}
37
38// takes care of hardness...
39double PatersonBuddCold::softness_from_temp(double T_pa) const {
40 return m_A_cold * exp(-m_Q_cold / (m_ideal_gas_constant * T_pa));
41}
42
43// ignores pressure and uses non-pressure-adjusted temperature
44double PatersonBuddCold::flow_from_temp(double stress, double temp,
45 double , double) const {
46 return softness_from_temp(temp) * pow(stress,m_n-1);
47}
48
49
50// Rather than make this part of the base class, we just check at some reference values.
51bool FlowLawIsPatersonBuddCold(const FlowLaw &flow_law, const Config &config,
53 static const struct {double s, E, p, gs;} v[] = {
54 {1e3, 223, 1e6, 1e-3}, {450000, 475000, 500000, 525000}, {5e4, 268, 5e6, 3e-3}, {1e5, 273, 8e6, 5e-3}};
55 PatersonBuddCold cpb("stress_balance.sia.", config, EC); // This is unmodified cold Paterson-Budd
56 for (int i=0; i<4; i++) {
57 const double left = flow_law.flow(v[i].s, v[i].E, v[i].p, v[i].gs),
58 right = cpb.flow(v[i].s, v[i].E, v[i].p, v[i].gs);
59 if (fabs((left - right)/left)>1.0e-15) {
60 return false;
61 }
62 }
63 return true;
64}
65
66} // end of namespace rheology
67} // end of namespace pism
A class for storing and accessing PISM configuration flags and parameters.
std::shared_ptr< EnthalpyConverter > Ptr
double m_A_cold
Paterson-Budd softness, cold case.
Definition FlowLaw.hh:139
double m_Q_cold
Activation energy, cold case.
Definition FlowLaw.hh:143
double flow(double stress, double enthalpy, double pressure, double grain_size) const
The flow law itself.
Definition FlowLaw.cc:88
double m_ideal_gas_constant
ideal gas constant
Definition FlowLaw.hh:152
double m_n
power law exponent
Definition FlowLaw.hh:154
double softness_from_temp(double T_pa) const
double tempFromSoftness(double A) const
Return the temperature T corresponding to a given value A=A(T).
PatersonBuddCold(const std::string &prefix, const Config &config, EnthalpyConverter::Ptr EC)
double flow_from_temp(double stress, double temp, double, double) const
The flow law (temperature-dependent version).
Cold case of Paterson-Budd.
Derived class of FlowLaw for Paterson-Budd (1982)-Glen ice.
bool FlowLawIsPatersonBuddCold(const FlowLaw &flow_law, const Config &config, EnthalpyConverter::Ptr EC)