  A deterministic excitation (DE) paradigm is formulated, according to which
the late Pleistocene glacial terminations correspond to the excitation, by the
orbital forcing, of nonlinear relaxation oscillations (ROs) internal to the
climate system in the absence of any stochastic parameterization. Specific
threshold crossing rules parameterizing the activation of internal climate
feedbacks leading to RO excitations are derived according to the DE assumption.
They are then applied to an energy balance model describing the fluctuations
induced by realistic orbital forcing on the glacial state. The timing of the
glacial terminations thus obtained in a reference simulation is found to be in
good agreement with proxy records. A sensitivity analysis insures the
robustness of the timing. The potential irrelevance of noise allowing DE to
hold is discussed, and a possible explanation of the 100-kyr cycle problem
based on DE is outlined. In conclusion, the DE paradigm characterizes in one of
the simplest possible ways the link between orbital forcing and glacial
terminations implied by the Milankovitch hypothesis.
