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Old 12-29-2018, 04:53 PM   #4348 (permalink)
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ice ages

I'm gonna start this thread and add to it as data comes along.
Ice ages and non-ice age periods,or,Glacial/Interglacials-Interstadials,are defined by glaciologists as pertaining to sea level.
Interglacials (complete deglaciation) are defined by high seal level,and marine oxygen isotope statigraphy.
Interstadials are incomplete interglacials.
Glaciation is attributed to a 2.4-million-year Earth orbital eccentricity cycle.A 1.2-million year orbital eccentricity.A 1.2-million -year obliquity cycle.And also affected by Milankovitch;orbital,tilt,and wobble cycles of 96,000-years,41,000-years,and 23,000-years,respectively.
Earth's orbit is perturbed by that of Mars,as: planetary ephemeris,secular resonances,precession of perihelion,and precession of the node,which contribute to a stochastic resonance transition in sensitivity of climate to obliquity forcing which can become the dominant 100,000-year climate cycle.
*Not all solar insolation maxima have led to interglacials
*Some prominant solar insolation peaks (maxima) are associated with incomplete deglaciations.
*Solar flux radiative forcing cannot by itself define ice-age dynamics.
*There is no single solar insolation threshold separating interglacials from interstadials throughout the Quarternary (last 2.6-million years)
*In the last ice-age,atmospheric CO2 was 180 ppmv (today it's 407 ppmv)
*Solar onsolation at the poles during warm seasons at the Equator is equally high regardless of obliquity.
*Stratospheric ozone absorbs 50% of incoming total solar insolation spectrum
*Poleward solar radiative forcing is actually lower during solar maximums due to ozone spectral opacity
*Higher atmospheric albedo can explain cooling
*Volcanic eruptions can affect global albedo
*Lower CO2 can explain cooling
*High obliquity at the poles enhances seasonality (you cannot have seasons without obliquity)
*Oceanic absorption (pH)and burial (phytoplankton/zooplankton) of carbon can lower atmospheric CO2.
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