Sentences with phrase «driven by internal variability»

Not exact matches

«Although this widening is considered a «natural» mode of climate variability, implying tropical widening is primarily driven by internal dynamics of the climate system, we also show that anthropogenic pollutants have driven trends in the PDO,» Allen said.

Despite your insistence otherwise, you evince at best a shallow understanding of basic principles of climate science (hint: while radiative forcing is known to be at least partially controlled by atmospheric CO2, no «natural», i.e. internal source of variability has been demonstrated that could drive a global temperature trend for half a century), as well as an inability to recognize genuine expertise.

(57k) When I state that the equilibrium climatic response must balance imposed RF (and feedbacks that occur), I am referring to a global time average RF and global time average response (in terms of radiative and convective fluxes), on a time scale sufficient to characterize the climatic state (including cycles driven by externally - forced cycles (diurnal, annual) and internal variability.

Recently I have been looking at the climate models collected in the CMIP3 archive which have been analysed and assessed in IPCC and it is very interesting to see how the forced changes — i.e. the changes driven the external factors such as greenhouse gases, tropospheric aerosols, solar forcing and stratospheric volcanic aerosols drive the forced response in the models (which you can see by averaging out several simulations of the same model with the same forcing)-- differ from the internal variability, such as associated with variations of the North Atlantic and the ENSO etc, which you can see by looking at individual realisations of a particular model and how it differs from the ensemble mean.

Roy Spencer is the driving force behind the «internal variability» hypothesis, which posits that some unknown and undefined mechanism is causing cloud cover to change, which, by changing the overall reflectivity of the Earth, is the driving force behind the current global warming.

Despite its fundamental problems, Spencer's internal variability hypothesis was probably the best alternative presented to this point, and Dessler drove another nail into its coffin by demonstrating what a small effect clouds have had on global temperature changes over the past decade.

«We build on this insight to demonstrate directly from ice - core data that, over glacial — interglacial timescales, climate dynamics are largely driven by internal Earth system mechanisms, including a marked positive feedback effect from temperature variability on greenhouse - gas concentrations.»

The temperature of the troposphere is constantly being affected by variations in the rate of energy flow from the oceans driven by internal ocean variability, possibly caused by temperature fluctuations along the horizontal route of the thermohaline circulation and by variations in energy flow from the sun that affect the size (and thus density) of the atmosphere and the rate of energy loss to space.

Like Dessler's paper, Santer et al. also drive another nail into the «warming due to internal variability» hypothesis by noting that although the trend may be smaller than models predict, it's still well outside the noise over the long - term:

While there may indeed be additional energy in the system as a result of greenhouse gases — it is set against a background of large natural variability driven by internal climate processes.

It is very unlikely that Northern Hemisphere temperature variations from 1400 to 1850 can be explained by natural internal variability alone; — something, such as changes in solar and / or volcanic activity, must have driven the changes.

The big question now becomes how much is anthropogenic forcing affecting the natural internal variability that formerly (prior to the mid-20th century) was driven by solar variability and ocean cycles.

So really forced = external and unforced = internal both terms relative to a specific system, but either is «natural variability» not driven by human activity.

Namely whether or not the AO is entirely driven by internal system variability or whether there is some solar influence.