Sentences with phrase «for volcanic forcing»

The low efficacy for volcanic forcing is expected, and partly reflects the delay in GMST reponse to a forcing impulse, which matters here as volcanic forcing is impulse like.

I also don't know how the wikipedia article gets its baseline for volcanic forcing.

However, the concept of efficacy implies that the value of lambda may vary between forcings; it may be higher for volcanic forcing than for most forcings, because it has peculiar effects.

I agree that Hansen et al 2005 does not show such a low efficacy for volcanic forcing, but they estimate an efficacy of 0.84 for the iRF from a «one third Pinatubo», which is some way below 1.0.

There was a strong role for volcanic forcing during the LIA — a fact which the «sun does everything» crowd seems to not fully grasp.

For ENSO I used the MEI index, for volcanic forcing I used data from Ammann et al. 2003, GRL 30, 1657.

Other studies have come up with other splits — including some which find a dominant role for volcanic forcing.

Not exact matches

Model simulations of 20th century global warming typically use actual observed amounts of atmospheric carbon dioxide, together with other human (for example chloroflorocarbons or CFCs) and natural (solar brightness variations, volcanic eruptions,...) climate - forcing factors.

Since the data show southern Greenland temperatures over the last 150 years, it would be most useful to look at model simulations for exactly that period, run with the best guesses for CO2, solar and volcanic forcing etc..

Furthermore, the pattern of solar and volcanic forcing is uncertain (e.g. Hoyt vs Lean for solar, robertson vs crowley for volcanic).

Such studies can reasonably account for the observed variations as a response to solar and volcanic forcing (and a few secondary things) with energy balance climate models tuned to have a climate sensitivity equivalent to 2.5 C per doubling of CO2.

All the quantified mechanisms involve forcings like volcanic and solar variability for the Holocene case, and CO2 and Milankovic (modified by the slow land - glacier response) for the LGM.

2000, except that they used a large forcing for solar (10x) and volcanic (5x) in separate runs to see if the relative influence of both may need to be adjusted, as the Hadcm3 model possibly underestimates the — relative — weaker forcings.

If the forcing due to a certain change of solar and / or volcanic activity should have been higher than previously assumed, this wouldn't change the weight of these factors much, neither for the Esper / Moberg period nor the period since 1950.

Therefore, the solar forcing combined with the anthropogenic CO2 forcing and other minor forcings (such as decreased volcanic activity) can account for the 0.4 °C warming in the early 20th century, with the solar forcing accounting for about 40 % of the total warming.

Constraining ECS from the observed responses to individual volcanic eruptions is difficult because the response to short - term volcanic forcing is strongly nonlinear in ECS, yielding only slightly enhanced peak responses and substantially extended response times for very high sensitivities (Frame et al., 2005; Wigley et al., 2005a).

The uncertainty in the overall amplitude of the reconstruction of volcanic forcing is also important for quantifying the influence of volcanism on temperature reconstructions over longer periods, but is difficult to quantify and may be a substantial fraction of the best estimate (e.g., Hegerl et al., 2006a).

The same forces that led to the most recent major volcanic event (a devastating 1957 eruption on the island of Faial that sent a wave of refugees to the U.S. and beyond) also make the Azores one of Europe's best destinations for mineral hot springs and geothermally - heated ocean lagoons.

He was coordinating with the immigration office to ensure the extension of visas for tourists forced to overstay due to the volcanic activity.

Mount Agung erupted in late November, spreading volcanic ash to nearby areas and forcing I Gusti Ngurah Rai International Airport and Lombok International Airports to close for several days.

Finally, look up Rahmstorf and Foster 2011 — it shows that if you account for El Nino, volcanic eruptions and changes in solar forcing, the warming has continued apace.

You can show quite easily that without water - vapour feedbacks (for instance), you can not get a good match to volcanic forcings and responses in the real world (Soden et al, 2005), or to ENSO, or to the long term trends.

Maybe someone would like to generate some examples using a basic red - noise process overlaid with a climate signal (for instance from solar or volcanic forcing histories) and then compute the auto - correlations?

you'll see the multi-model mean based on models driven by volcanic forcing is rejected at the 90 % confidence level for every year between 1960 and 1998.

Annually - resolved ice core and tree - ring chronologies provide opportunities for understanding past volcanic forcing and the consequent climatic effects and impacts on human populations.

Through paleo - climate simulations for the last millennium with climate models, a number of alternate forcing histories for volcanic and solar changes have been proposed to see their effect on past climate variations.

The interest in these records is for what they can tell us about natural variability, spatial patterns of change, responses to solar or volcanic forcing, teleconnections etc. — it's all interesting and useful, but it is nothing like as important as the outside interest shown in these studies might suggest.

gavin: You can show quite easily that without water - vapour feedbacks (for instance), you can not get a good match to volcanic forcings and responses in the real world (Soden et al, 2005)...

Almost equal contribution from human forcings, natural forcings (mainly recovery from large volcanic eruptions from 1883 to 1912), oceanic cycles, and uncorrected SST measurement errors for this period.

For larger forcings (say a big volcanic eruption), the signal can rise out of the weather «noise» more rapidly.

This subset only used the runs that included volcanic forcing and stratospheric ozone depletion — the most appropriate selection for this kind of comparison.

This should be done properly (and could be) but assuming the slight difference in period for the RAOBCORE v1.4 data or the selection of model runs because of volcanic forcings aren't important, then using the standard deviations in their Table IIa you'd end up with something like this:

Maybe a dumb question BUT since the «hockey stick» shows up in the sunspot curves in 20 above, in the Solanski 2002 Jeffreys lecture solar irradiance curves, in Be-10 curves etc etc, indicating a driving solar forcing for the hockey stick, then why doesn't it show up in the GCM models for natural only (see Is modelling science http://www.realclimate.org/index.php?p=100) Surely the volcanic forcings from one 1991 volcano can't dominate the sun?

Thus this period is not ideal for assessing the magnitude of natural changes (both intrinsic and forced by natural processes like solar variability or volcanic eruptions) since there is likely a contamination from human - related causes.

The difference in response between Zorita et al (2004) and Crowley (2000) is that the forcings were significantly larger in ECHO - G (by a factor of 2 for solar, and with larger volcanic forcing as well).

Climate models» transient response to forcing can be checked against the occurrence of equatorial volcanic eruptions, for example.

For instance, simulations were run that only used the changes in volcanic forcing, or in land use or in tropospheric aerosols.

2000, except that they used a large forcing for solar (10x) and volcanic (5x) in separate runs to see if the relative influence of both may need to be adjusted, as the Hadcm3 model possibly underestimates the — relative — weaker forcings.

All the quantified mechanisms involve forcings like volcanic and solar variability for the Holocene case, and CO2 and Milankovic (modified by the slow land - glacier response) for the LGM.

The portion associated with short term forcings (solar, unaccounted - for volcanic aerosols, undercounts of Chinese pollution) will depend on their long term evolution — if they stabilise, you'd get a delay.

If the forcing due to a certain change of solar and / or volcanic activity should have been higher than previously assumed, this wouldn't change the weight of these factors much, neither for the Esper / Moberg period nor the period since 1950.

Given the total irrelevance of volcanic aerosols during the period in question, the only very modest effect of fossil fuel emissions and the many inconsistencies governing the data pertaining to solar irradiance, it seems clear that climate science has no meaningful explanation for the considerable warming trend we see in the earlier part of the 20th century — and if that's the case, then there is no reason to assume that the warming we see in the latter part of that century could not also be due to either some as yet unknown natural force, or perhaps simply random drift.

We compared simulated temperature of the past millennium derived by driving theoretical climate models with estimated natural (volcanic + solar) and anthropogenic forcings for the past millennium.

For the CMIP5 simulations, there were no volcanic eruptions in the future forcing, yet some small eruptions had a small effect on the actual observations.

It is clear that the model fails for the dips in the forcing connected volcanic eruptions (Figure 1).

The argument that larger sensitivity for natural (mainly solar and volcanic) goes at the cost of the sensitivity for natural and man - made greenhouse gases, or enhanced variability during pre-industrial times, would result in a redistribution of weight towards the role of natural factors in forcing temperature changes, seems to rely on a model like the following: T = a * ANTHRO + b * NAT

Secondly, the conclusion at this stage simply a hypothesis, a hypothesis that can account for these key enigmatic features in the actual tree - ring hemisphere temperature reconstruction: the attenuation, and the increasing (back in time) delay and temporal smearing of the cooling response to past volcanic forcing.

The «lack of volcanic activity» has allowed the stratospheric aerosols responsible for such forcing to «dissipate» through the 1930s & 1940s.

For example, without understanding impacts of other forcings, predicting the effects of large volcanic eruption would not be possible.

Re: tropical vs high latitude volcanic eruptions — I know the effect is likely negligible, but tropical locations are selected for launches into space because of centripetal force, right?