Sentences with phrase «aerosol changes over»

Near - global satellite aerosol data imply a negative radiative forcing due to stratospheric aerosol changes over this period of about — 0.1 watt per square meter, reducing the recent global warming that would otherwise have occurred.

Note too that the models do include representations of aerosol changes over this period — though imperfectly.

Near - global satellite aerosol data imply a negative radiative forcing due to stratospheric aerosol changes over this period of about — 0.1 W / m2, reducing the recent global warming that would otherwise have occurred.

Not exact matches

The difference in lightning activity can't be explained by changes in the weather, according to the study's authors, who conclude that aerosol particles emitted in ship exhaust are changing how storm clouds form over the ocean.

A few of the main points of the third assessment report issued in 2001 include: An increasing body of observations gives a collective picture of a warming world and other changes in the climate system; emissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to affect the climate; confidence in the ability of models to project future climate has increased; and there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.

Similar scandals erupted over the effects of scores of industrial applications, ranging from sulfur dioxide and acid rain, to certain aerosols and the hole in the ozone layer, to leaded gas and cognitive impairment, to the granddaddy of them all, fossil fuels and global climate change.

Similarly (and perhaps relatedly), the magnitude of the change in aerosol forcing from ~ 1975 to present relative to the change in all forcings is much smaller than from pre-ind through present, which I think should make the TCR estimated over that period insensitive to the value of E.

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

The forcing over the last 150 years is around 1.6 W / m2 (including cooling effects from aerosols and land use change) but the climate is not (yet) in equilibirum, and so the full temperature response has not been acheived.

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.

Over the past several years, scientists from many institutions have explored the ability of SP - CAM to simulate tropical weather systems, the day - night changes of precipitation, the Asian and African monsoons, cloud - aerosol interactions and other climate phenomena.

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.

In addition, since the global surface temperature records are a measure that responds to albedo changes (volcanic aerosols, cloud cover, land use, snow and ice cover) solar output, and differences in partition of various forcings into the oceans / atmosphere / land / cryosphere, teasing out just the effect of CO2 + water vapor over the short term is difficult to impossible.

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

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.]

Also, due to the multiplicity of anthropogenic and natural effects on the climate over this time (i.e. aerosols, land - use change, greenhouse gases, ozone changes, solar, volcanic etc.) it is difficult to accurately define the forcings.

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.

As well as effective aerosol forcing of -1.2 W / m2 being mcuh stronger than the IPCC AR5 ERF of ~ -0.7 W / m2 over 1850 - 2000, the land use change effective forcing of -0.7 W / m2, arsign from a very high efficacy of 3.89, seems absurd to me.

The declining signal over India shown by the GPCP decadal mode is broadly consistent with gauge measurements since the 1950s — that several research groups including my own are trying to understand, perhaps relating to emissions of anthropogenic aerosol — although there are discrepancies between these gauge - based data sets themselves (see our recent review in Nature Climate Change, for example).

It is likely that at least some of this change, particularly over Europe, is due to decreases in pollution; most governments have done more to reduce aerosols released into the atmosphere that help global dimming instead of reducing CO2 emissions.

We also use five - member ensembles of simulations with greenhouse gas changes only (GHG), volcanic and solar irradiance changes only (NAT), and aerosol changes only (AER) over the period 1850 — 2010.»

Here we apply such a method using near surface air temperature observations over the 1851 — 2010 period, historical simulations of the response to changing greenhouse gases, aerosols and natural forcings, and simulations of future climate change under the Representative Concentration Pathways from the second generation Canadian Earth System Model (CanESM2).

The observed North Atlantic sulfate aerosol optical depth has not increased (but shows a modest decline) over this period, suggesting the decline of the Atlantic major hurricane frequency during 2005 — 2015 is not likely due to recent changes in anthropogenic sulfate aerosols.

The aerosol forcing change has been fairly flat over the last few decades according to the AR5 figure.

None of the models — not one of them — could match the change in mean global temperature over the past century if it did not utilise a unique value of assumed cooling from aerosols.

The model that I have described, warming due to the removal of anthropogenic SO2 aerosols, largely due to clean air efforts, perfectly matches the behavior of climate change over the past 40 years.

Finally onto point # 2 from above, not only can one adapt to a change similar to 1920's - > 1930's natural change over a ten year time span, we can also succesfully hold down temperatures with aerosols (if you're skeptical of this, you can't blame the current flat line on China's coal then, because we can surely do aerosols better when they are a deliberate end, rather than as an unintended by - product.)

Changes over the next few decades in the types of aerosol pollutants and where they are emitted will affect how climate cChanges over the next few decades in the types of aerosol pollutants and where they are emitted will affect how climate changeschanges.

«The results also show that ionisation of the atmosphere by cosmic rays accounts for nearly one - third of all particles formed, although small changes in cosmic rays over the solar cycle do not affect aerosols enough to influence today's polluted climate significantly.»

A few locations over land exhibit weak cooling over this time, perhaps a signature of the effects of increasing aerosol particles due to combustion and biomass burning, or a result of changes in land use.

Gregory and Oerlemans (1998) applied local seasonal temperature changes over 1860 to 1990 calculated by the HadCM2 AOGCM forced by changing greenhouse gases and aerosols (HadCM2 GS in Table 9.1) to the glacier model of Zuo and Oerlemans.

NASA's P - 3 research plane begins flights this month through both clouds and smoke over the South Atlantic Ocean to understand how aerosols change the properties of clouds.

Well, to make it work, the mechanism needs clean air (which you always had over at least parts of the oceans) and nucleating aerosols (e.g., as you get from DMS, which is primarily formed by phytoplankton which exists for a loooooong while), so yes, it is reasonable that the mechanism has been operational, though quantitatively it may have changed somewhat.

Anomalies in the volcanic - aerosol induced global radiative heating distribution can force significant changes in atmospheric circulation, for example, perturbing the equator - to - pole heating gradient (Stenchikov et al., 2002; Ramaswamy et al., 2006a; see Section 9.2) and forcing a positive phase of the Arctic Oscillation that in turn causes a counterintuitive boreal winter warming at middle and high latitudes over Eurasia and North America (Perlwitz and Graf, 2001; Stenchikov et al., 2002, 2004, 2006; Shindell et al., 2003b, 2004; Perlwitz and Harnik, 2003; Rind et al., 2005; Miller et al., 2006).

As humankind adds carbon dioxide, aerosol particles, and other nasty things to the atmosphere, we can expect our climate to change over the 21st Century, but it's not easy to predict how fast the climate should change and how it will change in different parts of the world.

Our understanding 48 of the «ion - aerosol clear air» mechanism as a whole relies on a few model investigations that simulate GCR 49 changes over a solar cycle (Kazil et al., 2012; Pierce and Adams, 2009a; Snow - Kropla et al., 2011) or during 50 strong Forbush decreases (Bondo et al., 2010; Snow - Kropla et al., 2011).

7.4.5.3 Synthesis Although there is some evidence that ionization from cosmic rays may enhance aerosol nucleation in the free troposphere, there is medium evidence and high agreement that the cosmic ray - ionization mechanism is too weak to influence global concentrations of CCN or their change over the last century or during a solar cycle in any climatically significant way.

They concluded that with a bit of help from changes in solar output and natural climatic cycles such as the El Nino Southern Oscillation (ENSO), the growth in the volume of aerosols being pumped up power station chimneys was probably enough to block the warming effect of rising greenhouse gas emissions over the period 1998 - 2008.

NASA's P - 3 research plane begins flights this month through both clouds and smoke over the South Atlantic Ocean to understand how tiny airborne particles called aerosols change the properties of clouds and how they influence the amount of incoming sunlight the clouds reflect or absorb.

Despite potentially large absolute errors in these forcings, their impact on our analysis is likely to be small, as the tropospheric aerosol forcing in the datasets analyzed changed very little over 1985 — 96 (Myhre et al. 2001).»

They state that tropospheric aerosol forcing in the datasets analysed (Myhre et al 2001) changed very little over 1985 - 1996, which I would have thought was the most important thing.

First, it is generally accepted that global forcing from aerosols has changed little over the well - observed period since 1980.

Although we focus on a hypothesized CR - cloud connection, we note that it is difficult to separate changes in the CR flux from accompanying variations in solar irradiance and the solar wind, for which numerous causal links to climate have also been proposed, including: the influence of UV spectral irradiance on stratospheric heating and dynamic stratosphere - troposphere links (Haigh 1996); UV irradiance and radiative damage to phytoplankton influencing the release of volatile precursor compounds which form sulphate aerosols over ocean environments (Kniveton et al. 2003); an amplification of total solar irradiance (TSI) variations by the addition of energy in cloud - free regions enhancing tropospheric circulation features (Meehl et al. 2008; Roy & Haigh 2010); numerous solar - related influences (including solar wind inputs) to the properties of the global electric circuit (GEC) and associated microphysical cloud changes (Tinsley 2008).

Greenhouse warming that is stronger over land and in the Northern Hemisphere tends to strengthen the monsoon, but increases in planetary albedo over the continent due to aerosol forcing and / or land - use change tend to weaken it.

Kristjánsson et al. (2008) adapted this idea to an investigation of FD events, performing a survey of cloud changes detected by MODIS over aerosol - impoverished oceanic regions.

How much could LLGHGs, ozone, aerosols, etc have changed over that period?

The report which contains statements like this: «Although there is some evidence that ionization from cosmic rays may enhance aerosol nucleation in the free troposphere, there is medium evidence and high agreement that the cosmic ray - ionization mechanism is too weak to influence global concentrations of CCN or their change over the last century or during a solar cycle in any climatically significant way.

Although there is some evidence that ionization from cosmic rays may enhance aerosol nucleation in the free troposphere, there is medium evidence and high agreement that the cosmic ray ionization mechanism is too weak to influence global concentrations of CCN or their change over the last century or during a solar cyclein any climatically significant way.

The new study by Herman et al. on change in the Lambert Equivalent Reflectivity (LER) of the Earth's cloud plus aerosol over the period 1979 - 2011 shows

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