def _theta_hat_amc_lh88(sinlat, sinlat_1, theta_hat_1, theta_ref,
                        del_h_over_ro):
    """Lindzen and Hou 1988 Eq. 7."""
    return (theta_hat_1 - 0.5*theta_ref*del_h_over_ro *
            (sinlat**2 - sinlat_1**2)**2 / (1 - sinlat**2))