More details about Crank-Nicolson method

[kongdd]

Dear @gbonan,

could you give more details about Crank-Nicolson method.

bonanmodeling/sp_05_03/soil_temperature.m

Lines 114 to 120 in a10cf76

	case 'Crank-Nicolson'
	for i = 2:soilvar.nsoi-1
	m = soilvar.cv(i) * soilvar.dz(i) / dt;
	a(i) = -0.5 * tk_plus_onehalf(i-1) / soilvar.dz_plus_onehalf(i-1);
	c(i) = -0.5 * tk_plus_onehalf(i) / soilvar.dz_plus_onehalf(i);
	b(i) = m - a(i) - c(i);
	d(i) = m * soilvar.tsoi(i) + 0.5 * (f(i) - f(i-1));

In the book, Table 5.1 is only for implicit formulation. The Crank-Nicolson method is more complex, but has no details, except Eq. 5.13.

Further references is appreciated.

Regards,
Dongdong