Sentences with phrase «orbital variations which»

«Milankovitch cycles» — natural orbital variations which primarily determine the timing of Ice Ages.

He then uses what information is available to quantify (in Watts per square meter) what radiative terms drive that temperature change (for the LGM this is primarily increased surface albedo from more ice / snow cover, and also changes in greenhouse gases... the former is treated as a forcing, not a feedback; also, the orbital variations which technically drive the process are rather small in the global mean).

Not exact matches

Prior to 2009, small but significant variations in radial velocity had been detected which may have been caused by a substellar companion of one to nine Jupiter - masses with an orbital period of 50 years of less (Campbell et al, 1988, pages 904, 906, and 919).

Periods of volcanism can cool the climate (as with the 1991 Pinatubo eruption), methane emissions from increased biological activity can warm the climate, and slight changes in solar output and orbital variations can all have climate effects which are much shorter in duration than the ice age cycles, ranging from less than a decade to a thousand years in duration (the Younger Dryas).

The consensus is that several factors are important: atmospheric composition (the concentrations of carbon dioxide, methane); changes in the Earth's orbit around the Sun known as Milankovitch cycles (and possibly the Sun's orbit around the galaxy); the motion of tectonic plates resulting in changes in the relative location and amount of continental and oceanic crust on the Earth's surface, which could affect wind and ocean currents; variations in solar output; the orbital dynamics of the Earth - Moon system; and the impact of relatively large meteorites, and volcanism including eruptions of supervolcanoes.

These orbital variations, which can be calculated from astronomical laws (Berger, 1978), force climate variations by changing the seasonal and latitudinal distribution of solar radiation (Chapter 6).

# 29 — the phenomenon of greenhouse gases retaining heat at the surface of the earth operates on decadal scales, and the orbital variations (Milankovitch cycles) which cause the waxing and waning of the ice ages operate on millennial scales, and both are fundamental physical processes, and are not elucidated by computer models.

Those are paced by orbital variations, which have nothing to do with solar activity.

And yes, there is such evidence — in the predicted response to volcanic forcing, the ozone hole, orbital variations, the sun, paleo - lake outbursts, the response to ENSO etc. that all show models matching the observations skillfully (which is not to say they match perfectly).

There is no modelling of any orbital variations in incoming energy, either daily, yearly or long term Milankovitch variations, based on the assumption that a global yearly average value has a net zero change over the year which is imposed on the energy forcing at the TOA and the QFlux boundary etc..

These are well described cycles, which have become known as Milankovitch cycles, after the name of the Russian scientist who for the first time in the 1920s was able to correlate these orbital and rotational variations (which other scientists had known about for many years) with the dates of various ice ages which had been more recently determined.

[Response: I presumed you meant short term variations in the orbital parameters (which we don't include).

What this model shows is that if orbital variations in insolation impact ice sheets directly in any significant way (which evidence suggests they do Roe (2006)-RRB-, then the regression between CO2 and temperature over the glacial - interglacial cycles (which was used in Snyder (2016)-RRB- is a very biased (over) estimate of ESS.

The orbital variations are astronomically parameterized as part of insolation, which is again the main boundary condition imposed on the system.

They are one driver of earth's orbital variations, which probably drive glacial cycles via ice - albedo and other feedbacks.

Increasing CO2 does increase the greenhouse effect, but there are other factors which determine climate, including solar irradiance, volcanism, albedo, orbital variations, continental drift, mountain building, variations in sea currents, changes in greenhouse gases, even cometary impacts.

If something triggers a cool spell, such as an orbital variation reducing incident sunlight, then water freezes at the poles, which increases the Earth's albedo, while the cooler oceans absorb more CO2, reducing the greenhouse effect.

There are variations in the amount of energy we receive from the sun due to factors like orbital patterns and sunspots, but none which can explain the current warming, according to the IPCC.

First, orbital tuning can increase the response by matching the signal times, but there's a limit to how far it can go — it simply can't inflate the physical amplitude of the response, which dominates the period analysis once the tuning is done, and it certainly can't impose temporal variations in the physical amplitude of the response.

But this is a case where we have theory to guide us, based on the orbital variations, which is better than relying on extrapolating past cycles — William]