Sentences with phrase «for aerosol effect»

This is 1.28 degrees minus largest guesstimate with a straight face for aerosol effect.

For example, Bayesian analyses differ in the strength of evidence they find for an aerosol effect.

They also use assumed histories for aerosol effects (cooling) which are adjusted so that the models sort - of match the historical temperature trends.

Not exact matches

The effect also illustrates one proposal for so - called geoengineering — the deliberate, large - scale manipulation of the planetary environment — that would use various means to create such sulfuric acid aerosols in the stratosphere to reflect sunlight and thereby hopefully forestall catastrophic climate change.

Aerosols can also have big effects on clouds, for instance making them brighter so that they reflect more sunlight back into space.

Mission leaders were relieved and eager to begin their studies of cloud and haze effects, which «constitute the largest uncertainties in our models of future climate — that's no exaggeration,» says Jens Redemann, an atmospheric scientist at NASA's Ames Research Center in Mountain View, California, and the principal investigator for ObseRvations of Aerosols above CLouds and their IntEractionS (ORACLES).

Indeed, the reduction in the emission of precursors to polluting particles (sulphur dioxide) would diminish the concealing effects of Chinese aerosols, and would speed up warming, unless this effect were to be compensated elsewhere, for instance by significantly reducing long - life greenhouse gas emissions and «black carbon.»

Yet there is no doubt that research into atmospheric aerosols is becoming increasingly important due to the effects that they can have on the global temperature of Earth, given that solar radiation is the main source of energy for Earth - Atmosphere system.

For this reason, a group of researchers from Extremadura (Spain) and Portugal has analysed the radiative effect of a type of natural aerosol (the dust from the desert areas), of great interest to the Iberian Peninsula due to the proximity of the Sahara desert.

«Scientists have talked about Arctic melting and albedo decrease for nearly 50 years,» said Ramanathan, a distinguished professor of climate and atmospheric sciences at Scripps who has previously conducted similar research on the global dimming effects of aerosols.

Jack added: «Dust is one of the most important aerosols for both the climate and the biology of an environment, and so understanding the amount of dust produced, and the distance and direction it travels is vital to allow us to understand its effect better.»

What's more, according to Tim Bates of the National Oceanic and Atmospheric Administration (NOAA), «there's a very wide range of sizes [for aerosol particles], and the effect that the particle is going to have on climate is going to be very dependent on its size, which makes it trickier.»

IPCC scientists have suspected for a decade that aerosols of smoke and other particles from burning rainforest, crop waste and fossil fuels are blocking sunlight and counteracting the warming effect of carbon dioxide emissions.

This is one of the best examples of why aerosol mixing state is so important for modeling the effect of aerosols on climate.

My main problem with that study is that the weather models don't use any forcings at all — no changes in ozone, CO2, volcanos, aerosols, solar etc. — and so while some of the effects of the forcings might be captured (since the weather models assimilate satellite data etc.), there is no reason to think that they get all of the signal — particularly for near surface effects (tropospheric ozone for instance).

Now if this was the 1980s they might have had a point, but the fact that aerosols are an important climate forcing, have a net cooling effect on climate and, in part, arise from the same industrial activities that produce greenhouse gases, has been part of mainstream science for 30 years.

Sally, who was nominated by Dr. Beat Schmid, Associate Director, Atmospheric Sciences and Global Change Division, was honored for her exceptional contribution in the field of atmospheric science, particularly in her efforts to improve understanding of the radiative effect of clouds and aerosols on the Earth's atmosphere and their representation in climate models.

For another discussion (where to find the effect of aerosols) I was looking for more or less reliable rural station data for North - West Russia for the period 1945 - 20For another discussion (where to find the effect of aerosols) I was looking for more or less reliable rural station data for North - West Russia for the period 1945 - 20for more or less reliable rural station data for North - West Russia for the period 1945 - 20for North - West Russia for the period 1945 - 20for the period 1945 - 2004.

The net effect of human - generated aerosols is more complicated and regionally variable — for example, in contrast to the local warming effect of the Asian Brown Cloud, global shipping produces large amounts of cooling reflective sulphate aerosols: http://www.sciencedaily.com/releases/1999/08/990820022710.htm

Microphysical effects determine macrophysical response for aerosol impacts on deep convective clouds, Proc Natl Acad Sci U S A, Early Edition online the week of November 11 - 15, 2013, DOI: 10.1073 / pnas.1316830110.

This mis - representation and can have significant ramifications for estimating the direct and indirect effects of aerosols on climate.

For sulphate aerosols, current models probably overestimate their influence, as there is no measurable effect of the large (over 60 %) reduction in SO2 emissions in Europe at the places where the largest influence should be visible, according to the models.

To provide guidance for future high - resolution simulations, Dai et al. used a computationally cheaper, two - dimensional chemical transport model to systematically estimate the effects of injecting sulfur dioxide and sulfate aerosols at a range of altitudes, latitudes, and time frames for 62 separate scenarios.

The top priorities should be reducing uncertainties in climate sensitivity, getting a better understanding of the effect of climate change on atmospheric circulation (critical for understanding of regional climate change, changes in extremes) and reducing uncertainties in radiative forcing — particularly those associated with aerosols.

Only a few estimates account for uncertainty in forcings other than from aerosols (e.g., Gregory et al., 2002a; Knutti et al., 2002, 2003); some other studies perform some sensitivity testing to assess the effect of forcing uncertainty not accounted for, for example, in natural forcing (e.g., Forest et al., 2006; see Table 9.1 for an overview).

Most studies consider a range of anthropogenic forcing factors, including greenhouse gases and sulphate aerosol forcing, sometimes directly including the indirect forcing effect, such as Knutti et al. (2002, 2003), and sometimes indirectly accounting for the indirect effect by using a wide range of direct forcing (e.g., Andronova and Schlesinger, 2001; Forest et al., 2002, 2006).

For example, they predicted the expansion of the Hadley cells, the poleward movement of storm tracks, the rising of the tropopause, the rising of the effective radiating altitude, the circulation of aerosols in the atmosphere, the modelling of the transmission of radiation through the atmosphere, the clear sky super greenhouse effect that results from increased water vapor in the tropics, the near constancy of relative humidity, and polar amplification, the cooling of the stratosphere while the troposphere warmed.

Does this result suggest, since in the paper for the last decade stratospheric aerosols are low / flat, and since TSI is relatively flat and has small effect, that the recent fluctuation of global temperatures is mostly ENSO related?

And it doesn't change the fundamental fact that human emissions of CO ₂ are almost certainly responsible for more than 100 % of the observed warming, once the effect of aerosols is accounted for.

What it shows is the effect of the structural uncertainty in individual GCMs (meaning that some of them are systematically high, others systematically low, due to flaws in the representation of the physics; most probably related to discretization / parametrization effects for clouds and / or aerosols).

And as for IPCC changing conclusions this has happened many times — Lindzen used to point to statements about upper tropospheric water vapour for instance that became less confident from the 1990, 1995 and 2001 reports, similarly uncertainty in aerosol indirect effects has clearly grown over time.]

There is very high confidence that the net 20th C aerosol effect was a cooling — mostly because estimates of tropospheric sulphate aerosols dominate the changes, and because BC and OC changes for many sources almost balance out.

Perhaps the thresholds for a CRF - cloud correlation was higher then than it has been for the past 40 years (one might imagine that in periods where the air is rather clear of man made aerosols, the threshold for CRF effects on cloud formation become higher... and so on).

Subsequent work (for instance by Drew Shindell) has shown that the simplified EBMs are missing important transient effects associated with aerosols, and so the divergence is very likely less than AR5 assessed.

Similarly, we have not been able to tell how much of the aerosol is capable of interacting with liquid or ice clouds (which depends on the different aerosols» affinity for water), and that impacts our assessment of the aerosol indirect effect.

But models are not tuned to the trends in surface temperature, and as Gavin noted before (at least for the GISS model), the aerosol amounts are derived from simulations using emissions data and direct effects determined by changes in concentrations.

There are an ever increasing number of these «indirect effects», but the two most discussed are the aerosol / cloud opacity interaction (more aerosols provide more sites for water to condense in clouds, thus cloud droplets are smaller and clouds become more opaque), and the cloud lifetime effect (smaller droplets make it more difficult to make drops big enough to rain, and so clouds live longer).

The fraction of the light that scatters back out to space is responsible for the increased albedo and the cooling effect from sulfate aerosols.

In a forthcoming paper Andreae, Jones and Cox calculate the relationship — they show that were there no aerosol effect at all, the implied sensitivity would be just 1.3 K for a doubling of CO2 — well below the IPCC - TAR range of 2.0 - 5.1 K.

While there is good data over the last century, there were many different changes to planet's radiation balance (greenhouse gases, aerosols, solar forcing, volcanoes, land use changes etc.), some of which are difficult to quantify (for instance the indirect aerosol effects) and whose history is not well known.

Unfortunately they also have to apply figures for forcing whose values and effects are not known and have ongoing debate about them, reflective aerosols, land use, black carbon etc etc..

This is a peer reviewed paper by respected scientists who are saying that aerosol forcing means that the majority of the warming caused by existing co2 emission has effectively been masked thus far, and that as aerosols remain in the atmosphere for far shorter a duration of time than co2, we will have already most likely crossed the 2 degree threshold that the G8 politicians have been discussing this week once the cooling effect of aerosols dissipate.

Moreover, the heat content of the oceans increased more in the NH than in the SH (again, if corrected for area), while 90 % of the aerosols are emitted and have their effect in the NH.

I was thinking instead perhaps more easily controlled polar - orbit satellites might be used, which would rotate with some fixed ratio to their orbital period, casting greater shadows at higher latitudes... or some other arrangment... for a targetted offset polar amplification of AGW especially and in particular perhaps avoiding the reduction in precipitation that can be caused by SW - radiation - based «GE» (although aerosols that actually absorb some SW in the troposphere while shielding the surface would have the worst effect in that way, I'd think)... strategic distribution of solar shading has been suggested with precipitation effects in mind, such as here... sorry, I don't have the link (I'm sure I saved it, just as Steve Fish would suggest — but where?).

What are you thinking about a fight against this effect by, for example, the injection in the higher tropsphere of very tiny (1 to 5 microns) aerosols?

... and all by itself... woops... a possible isolated, independent temperature rise of 3 - 5 degrees C average world surface temperatures by 2100, not even including any other positive forcings, because the forcing is already there waiting for the cancelling aerosol cooling effect to be removed...

Inclusion of calculated indirect effects from aerosols for instance or if unknown / un-included forcings are significant this may lead to more model - obs disagreements.

However, under a climate mitigation scenario for the twenty - first century in which sulphate aerosols decline before atmospheric CO2 is stabilized, this «diffuse - radiation» fertilization effect declines rapidly to near zero by the end of the twenty - first century.»

In other words, if we are after a cause (or causes) for the temperature increase during the period in question, the presence or absence of aerosols from volcanic eruptions is beside the point, because they can not explain any increase in temperatures that occurred prior to any cooling effect they might have had.

Similarly, if the IPCC concludes that something is highly uncertain (such as the magnitude of changes in aerosol indirect effects), then there are no good grounds for assuming otherwise.