Sentences with phrase «based on aerosol»

Not exact matches

Two years later, the National Academy of Sciences agreed, and by 1978 the U.S. government had ordered a ban on CFC - based aerosol sprays.

This critical question is addressed using simulations from climate models based on projections of future emissions of greenhouse gases and aerosols.

The report is based on the JRC's Emissions Database for Global Atmospheric Research (EDGAR), which is not only unique in its space and time coverage, but also in its completeness and consistency of the emissions compilations for multiple pollutants: the greenhouse gases (GHG), air pollutants and aerosols.

The theory of dangerous climate change is based not just on carbon dioxide warming but on positive and negative feedback effects from water vapor and phenomena such as clouds and airborne aerosols from coal burning.

The conclusions are based on observed gas and aerosol composition, humidity and temperature data collected at a site in rural Alabama as part of the Southern Oxidant and Aerosol Study aerosol composition, humidity and temperature data collected at a site in rural Alabama as part of the Southern Oxidant and Aerosol Study Aerosol Study (SOAS).

Yu and his colleagues analyzed dust transport estimates based on data collected by NASA's Cloud - Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite between 2007 and 2013.

The cooling effect of aerosols can partly offset global warming on a short - term basis, but many are made of organic material that comes from sources that scientists don't fully understand, said Joost de Gouw, a research physicist at NOAA's Earth System Research Laboratory in Boulder, Colo., who is unaffiliated with the studies.

-- As used in this section, the term «black carbon» means primary light absorbing aerosols, as defined by the Administrator, based on the best available science.

Therefore studies based on observed warming have underestimated climate sensitivity as they did not account for the greater response to aerosol forcing, and multiple lines of evidence are now consistent in showing that climate sensitivity is in fact very unlikely to be at the low end of the range in recent estimates.

I used was the surface temperature responses from histAll --(histGHG + histNatural) to obtain the response to aerosols + ozone + land - use and derive the enhancement of the response for that case relative to WMGHGs that I called E. Calculation of TCR based on histAll in a model is approximately the same as calculating the sum of responses to histGHG, histNat, and histInhomogeneous where the latter includes the factor E.

However, to make climate models more accurate, we are focused on developing a better understanding of the dynamics of organic aerosols formed from plant - based organic vapors and their interaction with aerosols emitted from human activities,» said Dr. Chen Song, a PNNL atmospheric scientist.

On high biomass burning days, both biomass burning and human - based activities equally contributed to levels of secondary organic aerosol downwind of Mexico City.

And finally, current theories based on greenhouse gas increases, changes in solar, volcanic, ozone, land use and aerosol forcing do a pretty good job of explaining the temperature changes over the 20th Century.

First computer model simulation of aerosol production done based on laboratory measurements

Most of the non-model estimates of climate sensitivity are based on the analyses using other forcings such as solar and aerosols, and the assumption that sensitivity to CO2 will be the same, despite the differences in way these forcings couple to the climate system.

The upper tail is particularly long in studies using diagnostics based on large - scale mean data because separation of the greenhouse gas response from that to aerosols or climate variability is more difficult with such diagnostics (Andronova and Schlesinger, 2001; Gregory et al., 2002a; Knutti et al., 2002, 2003).

Similarly, Gregory et al. (2002a) apply an inverse estimate of the range of aerosol forcing based on fingerprint detection results.

«We developed and implemented new modeling approaches based on laboratory measurements to include shielding of toxics by organic aerosols in a global atmosphere model that resulted in large improvements of model predictions,» said PNNL scientist Dr. Manish Shrivastava.

Forster and Gregory (2006) estimate ECS based on radiation budget data from the ERBE combined with surface temperature observations based on a regression approach, using the observation that there was little change in aerosol forcing over that time.

Ice sheet albedo forcing is estimated to have caused a global mean forcing of about — 3.2 W m — 2 (based on a range of several LGM simulations) and radiative forcing from increased atmospheric aerosols (primarily dust and vegetation) is estimated to have been about — 1 W m — 2 each.

Her research experience includes modeling of organic aerosol oxidation at LBNL, fabrication and optimization of high performance semiconductor nanoparticle - based image sensors as Manager of Materials Development at InVisage Technologies, Inc., and foundational and applied research as a Research Staff Member at IBM's Almaden Research Center on transformations in dielectrics, semiconductors, metals, and polymer films.

From its base in Namibia, the Observations of Clouds above Aerosols and their Interactions (ORACLES) study will use airborne instruments this fall to probe the impact on climate and rainfall of the interaction between clouds over the southeastern Atlantic Ocean and smoke from vegetation burning in southern Africa.

They determine the probability of combinations of climate sensitivity and net aerosol forcing based on the fit between simulations and observations (see Section 9.6 and Supplementary Material, Appendix 9.

Forward model approaches to estimating aerosol forcing are based on estimates of emissions and models of aerosol physics and chemistry.

Here a beautiful collaboration between El Mac, Augustine Kofie and Joseph «Nuke» Montalvo in Los Angeles The portrait was painted entirely with aerosol and fatcaps, and is based on

From the Physical Science Basis: «Shindell et al. (2009) estimated the impact of reactive species emissions on both gaseous and aerosol forcing species and found that ozone precursors, including methane, had an additional substantial climate effect because they increased or decreased the rate of oxidation of SO2 to sulphate aerosol.

According to «Atmospheric particles and nuclei» by Götz et al. (1991), Junge (1963) proposed on the basis of aerosol measurements that «large» and «giant» particles (radius greater than 0.1 micro-meter) constitute the majority of CCN, independently of their chemical composition.

Should this prove to be significant, climate models will likely incorporate this directly (using embedded aerosol codes), or will parameterise the effects based on calculated cloud variations from more detailed models.

My best guess from browsing Chapter 8 of the Physical Science Basis is that given the high uncertainty in the indirect effect on aerosols, the decision was to report GWPs that don't include these effects.

Based on NASA's CMIP5 forcing model, year 2012 has a greenhouse forcing of 3.54 Wm2, ozone has 0.45 Wm2, atmospheric aerosols have -0.89 Wm2 combined direct / indirect, and land use has -0.19 Wm2, all based onBased on NASA's CMIP5 forcing model, year 2012 has a greenhouse forcing of 3.54 Wm2, ozone has 0.45 Wm2, atmospheric aerosols have -0.89 Wm2 combined direct / indirect, and land use has -0.19 Wm2, all based onbased on iRF.

In this case, the vast preponderance of evidence and theory (such as long established basic physics) is on the side of AGW, so there would have to be a serious paradigm shift based on some new physics, a cooling trend (with increasing GHG levels and decreasing aerosol effect), and that they had failed to detect the extreme increase in solar irradiance to dislodge AGW theory.

Based on what I have read about aerosols, cloud behaviour and solar, in my opinion the real response to 2xCO2 may be at (or even below) the low - end scenario of the IPCC...

Therefore studies based on observed warming have underestimated climate sensitivity as they did not account for the greater response to aerosol forcing, and multiple lines of evidence are now consistent in showing that climate sensitivity is in fact very unlikely to be at the low end of the range in recent estimates.

As for longer trends, there are of course other factors that could play a role, but you perhaps don't realise that the association of the trends over the last few decades with human forcings (which include other GHGs, aerosols, land use, ozone depletion etc.) are not just based on a correlations.

The attraction of the proposal is that we are already conducting an uncontrolled experiment on aerosol - based geoengineering, through the sulfate aerosols injected into the troposphere by dirty coal plants.

The Nature commentary by Penner et al. on which this argument is based actually says that on top of the global warming caused by carbon dioxide, other short - lived pollutants (such as methane and black carbon) cause an additional warming approximately 65 % as much as CO2, and other short - lived pollutants (such as aerosols) also cause some cooling.

The question to ask modelers is whether they have done sensitivity studies, and then examine the range of answers based on the high / low values of aerosols forcings that have empirical support based on in - field measurements.

In this approach based on detection and attribution methods, which is compared with other approaches for producing probabilistic projections in Section 10.5.4.5, different scaling factors are applied to the greenhouse gases and to the response to other anthropogenic forcings (notably aerosols); these separate scaling factors are used to account for possible errors in the models and aerosol forcing.

«On the Theoretical and Empirical Basis for Apportioning Extinction by Aerosols: A Critical Review.»

So... the short is: including aerosols is not just a fudge like predicting stock market prices based on Superbowl winners (or even less loonie things, but just using way too many.)

Aerosols are a known forcing, and variations in insolation are generally treated separately based on satellite observations.

That means: in fairness, at a minimum, you need to give modelers credit for trying to provide true forcasts based on the forcing estimates for aerosols, and those forecasts were tested against data.

However, detection and attribution analyses based on climate simulations that include these forcings, (e.g., Stott et al., 2006b), continue to detect a significant anthropogenic influence in 20th - century temperature observations even though the near - surface patterns of response to black carbon aerosols and sulphate aerosols could be so similar at large spatial scales (although opposite in sign) that detection analyses may be unable to distinguish between them (Jones et al., 2005).

The IPCC model projections of future warming based on the varios SRES and human emissions only (both GHG warming and aerosol cooling, but no natural influences) are shown in Figure 6.

So the whole basis for the study is flawed — its based on the affect of increasing aerosol concentrations that actually are not increasing.

DK12 compounded their erroneous analysis by attempting to calculate the net climate feedback based solely on their estimated 2002 - 2008 OHC increase for the uppermost 700 meters, and only considering the CO2 and solar radiative forcings, ignoring the significant aerosol forcing, for example.

Based on evidence from Earth's history, we suggest here that the relevant form of climate sensitivity in the Anthropocene (e.g. from which to base future greenhouse gas (GHG) stabilization targets) is the Earth system sensitivity including fast feedbacks from changes in water vapour, natural aerosols, clouds and sea ice, slower surface albedo feedbacks from changes in continental ice sheets and vegetation, and climate — GHG feedbacks from changes in natural (land and ocean) carbon sinks.

This relationship between cumulative emissions and warming is not perfect, as it will change based on what happens to non-CO2 greenhouse gases, such as methane and nitrous oxide, as well as how quickly climate - cooling aerosols are reduced.

Additionally, changes in anthropogenic sulfate aerosol forcing have been proposed as the dominant cause of the AMV and the historical multidecadal variations in Atlantic tropical storm frequency, based on some model simulations including aerosol indirect effects.

I guess that this is based on the assumption that the range of total aerosol forcing is correct in the IPCC assessment: -1.2 w / m2 -LSB--2.7 to -0.4] http://www.skepticalscience.com/despite-uncertainty-CO2-drives-the-climate.html That central value is almost on par with the CO2 forcing (+1.6), thus canceling most of it.