Jean-Louis Pinault: /* Mid-Pleistocene transition (MPT) */
The many questions raised by the theory of orbital forcing of the climate system reflect that changes in the forcing are too small to explain the observed climate variations as simple linear responses. As suggested by some authors <ref name=":0">Liquid error: wrong number of arguments (given 1, expected 2)</ref><ref>Liquid error: wrong number of arguments (given 1, expected 2)</ref>, non-linear interactions occur between small changes in the Earth's orbit and internal oscillations of the climate system.
Consequently, to strictly apply the Milankovitch’s theory, a mediator involving positive feedbacks must be found, endowing the climate response with a resonant feature. Supported by both observational and theoretical considerations, a recent work approaches the Milankovitch’s theory in a new way in which the solar and orbital forcing of the climate system occurs under the mediation of very long-period Rossby waves winding around the subtropical gyres. Due to their specific properties, the so-called Gyral Rossby Waves (GRWs) are resonantly forced in subharmonic modes. This means that the forcing efficiency strongly depends on the deviation between the forcing period and the closest natural period of GRWs among the different subharmonic modes <ref>Liquid error: wrong number of arguments (given 1, expected 2)</ref>.
== Mid-Pleistocene transition (MPT) ==
The amplitude of orbital forcing related to the obliquity, whose period is 41 Ka, is much higher than that related to the eccentricity. That is why, before the MPT, the dominant ice age-interglacial period was 41 Ka.
Since the MPT, the dominant period has been coherent with that of eccentricity while it was approaching since 1.2 Ma BP to the period related to the subharmonic mode namely 98.3 Ka. The forcing efficiency related to that period has been increasing steadily since 1.4 Ma BP, which suggests that the tuning is still improving <ref>Liquid error: wrong number of arguments (given 1, expected 2)</ref>.
== References ==
[[Category:Climatology]]
[[Category:Physical oceanography]]
[[Category:Paleoclimatology]]
[[Category:Events that forced the climate]]
[[Category:Ice ages]]
[[Category:Pleistocene]]
Consequently, to strictly apply the Milankovitch’s theory, a mediator involving positive feedbacks must be found, endowing the climate response with a resonant feature. Supported by both observational and theoretical considerations, a recent work approaches the Milankovitch’s theory in a new way in which the solar and orbital forcing of the climate system occurs under the mediation of very long-period Rossby waves winding around the subtropical gyres. Due to their specific properties, the so-called Gyral Rossby Waves (GRWs) are resonantly forced in subharmonic modes. This means that the forcing efficiency strongly depends on the deviation between the forcing period and the closest natural period of GRWs among the different subharmonic modes <ref>Liquid error: wrong number of arguments (given 1, expected 2)</ref>.
== Mid-Pleistocene transition (MPT) ==
The amplitude of orbital forcing related to the obliquity, whose period is 41 Ka, is much higher than that related to the eccentricity. That is why, before the MPT, the dominant ice age-interglacial period was 41 Ka.
Since the MPT, the dominant period has been coherent with that of eccentricity while it was approaching since 1.2 Ma BP to the period related to the subharmonic mode namely 98.3 Ka. The forcing efficiency related to that period has been increasing steadily since 1.4 Ma BP, which suggests that the tuning is still improving <ref>Liquid error: wrong number of arguments (given 1, expected 2)</ref>.
== References ==
[[Category:Climatology]]
[[Category:Physical oceanography]]
[[Category:Paleoclimatology]]
[[Category:Events that forced the climate]]
[[Category:Ice ages]]
[[Category:Pleistocene]]
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