ENSORechargeOscillator

ENSORechargeOscillator(
    var_name='enso_recharge_oscillator',
    mu=0.7,
    en=0.0,
    c=1.0,
    r=0.25,
    alpha=0.125,
    b0=2.5,
    gamma=0.75,
    state_variables=None,
    diagnostic_variables=None,
    *args,
    **kwargs,
)

Jin-style ENSO recharge oscillator.

Couples the eastern Pacific SST anomaly T to the thermocline depth anomaly h via a nonlinear recharge-discharge mechanism:

dT/dt = R*T + gamma*h - en*(h + b*T)^3
dh/dt = -r*h - alpha*b*T

where b = b0*mu and R = gamma*b - c.

Seasonal or any other external forcing is added through the standard :meth:~climatecritters.core.CCModel.register_forcing interface::

from climatecritters.utils.forcing import create_sinusoid_forcing

model = ENSORechargeOscillator()
model.register_forcing(
    'T',
    create_sinusoid_forcing(A=0.5, period=6.0),
    attachment_style='additive',
    timing='pre',
)

Parameters

var_name : str = 'enso_recharge_oscillator': Label for the model output. Default 'enso_recharge_oscillator'.
mu : float or callable or cc.Forcing = 0.7: Bjerknes coupling coefficient. Default 0.7.
en : float or callable or cc.Forcing = 0.0: Nonlinear damping coefficient. Default 0.0 (linear limit).
c : float or callable or cc.Forcing = 1.0: Newtonian cooling rate of SST. Default 1.0.
r : float or callable or cc.Forcing = 0.25: Thermocline recharge damping rate. Default 0.25.
alpha : float or callable or cc.Forcing = 0.125: Wind-stress feedback strength. Default 0.125.
b0 : float or callable or cc.Forcing = 2.5: Background thermocline slope sensitivity. Default 2.5.
gamma : float or callable or cc.Forcing = 0.75: Thermocline feedback onto SST. Default 0.75.

Notes

State vector: [T, h] — eastern Pacific SST anomaly and thermocline depth anomaly.

References

Jin, F.-F. (1997). An equatorial ocean recharge paradigm for ENSO. J. Atmos. Sci., 54, 811–829.

Examples

import matplotlib.pyplot as plt
import climatecritters as cc
from climatecritters.model_critters.enso_recharge import ENSORechargeOscillator
from climatecritters.utils.forcing import create_sinusoid_forcing

model = ENSORechargeOscillator(mu=0.75)
model.register_forcing(
    'T',
    create_sinusoid_forcing(A=0.5, period=6.0),
    attachment_style='additive',
    timing='pre',
)
output = model.integrate(t_span=(0, 120), y0=[0.5, 0.0], method='RK45')
ts = output.to_pyleo(var_names=['T'])
ts.plot()
plt.savefig('docs/reference/figures/ENSORechargeOscillator_example.png',
            dpi=150, bbox_inches='tight')