Sentences with phrase «aerosol concentrations by»

Not exact matches

By analyzing satellite data and other measures, Daniel and his colleagues found that such aerosols have been on the rise in Earth's atmosphere in the past decade, nearly doubling in concentration.

After allowing for humidity and rainfall, they found that «aerosol optical thickness» — a measure of the concentration of atmospheric particles — decreased by only 10 to 15 per cent compared with the same periods in 2002 to 2007 (Geophysical Research Letters, in press).

By measuring the amount of laser light reflected back to Earth, the researchers could estimate the concentrations of aerosols at various altitudes.

By adjusting elements of the test, such as the air exchange rate, which is the number of times per hour indoor air is replaced by outdoor air, as well as the concentrations of terpene and ozone in the chamber, the group was able to ascertain how those variables each affected the formation of secondary organic aerosolBy adjusting elements of the test, such as the air exchange rate, which is the number of times per hour indoor air is replaced by outdoor air, as well as the concentrations of terpene and ozone in the chamber, the group was able to ascertain how those variables each affected the formation of secondary organic aerosolby outdoor air, as well as the concentrations of terpene and ozone in the chamber, the group was able to ascertain how those variables each affected the formation of secondary organic aerosols.

Rosenfeld and his colleagues are now working on a project to do exactly that by studying aerosol concentrations over Houston, where the team also has access to a dedicated lightning - mapping array.

Therefore, considering the large contribution of these particles to the aerosol mass concentration in the atmosphere and the importance of the INPs, we study the ability of these particles as INPs by immersion freezing mode.

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.

«In a scenario of zeroed CO2 and sulfate aerosol emissions, whether the warming induced by specified constant concentrations of non-CO2 greenhouse gases could slow the CO2 decline following zero emissions or even reverse this trend and cause CO2 to increase over time is assessed.

Such factors include increased greenhouse gas concentrations associated with fossil fuel burning, sulphate aerosols produced as an industrial by - product, human - induced changes in land surface properties among other things.

CO % 3B2 I would expect that eruptions that cause more cooling, which slow the evaporation / rainfall cycle, would lengthen the time for the aerosol concentration to drop by 1 / e.

The composition of sea spray aerosol particles are influenced by both chlorophyll - a concentrations and microbial degradation.

The Single Particle Soot Photometer (SP2) measures the soot (black carbon) mass of individual aerosol particles by laser - induced incandescence down to concentrations as low as ng / m ^ 3.

«We show that the control of the droplet concentration (N), the environmental carrying - capacity (H0), and the cloud recovery parameter (τ) can be linked by a single nondimensional parameter (μ = √ N / (ατH0)-RRB-, suggesting that for deeper clouds the transition from open (oscillating) to closed (stable fixed point) cells will occur for higher droplet concentration (i.e., higher aerosol loading)...

Climate projection — A projection of the response of the climate system to emission or concentration scenarios of greenhouse gases and aerosols, or radiative forcing scenarios, often based upon simulations by climate models.

However, I am not a «warmista» by any means — we do not know how to properly quantify the albedo of aerosols, including clouds, with their consequent negative feedback effects in any of the climate sensitivity models as yet — and all models in the ensemble used by the «warmistas» are indicating the sensitivities (to atmospheric CO2 increase) are too high, by factors ranging from 2 to 4: which could indicate that climate sensitivity to a doubling of current CO2 concentrations will be of the order of 1 degree C or less outside the equatorial regions (none or very little in the equatorial regions)- i.e. an outcome which will likely be beneficial to all of us.

This study of course does not take away very different concerns related to stratospheric aerosol SRM geoengineering, like possible damage to the ozone layer [which in turn would be good news if you hate waiting for that spring tan] and the fact that allowing CO2 concentrations to keep rising presents other problems, like the necessity to never stop with the active process of SRM geoengineering, and increasing ecological damage caused by ocean acidification.

«The forcings for ECHO - G are selected in advance by (1) choosing the strength and time series of solar irradiance variability; (2) choosing the strength and time series of volcanic aerosol variability and converting this to a surrogate time series of solar irradiance reductions, which are then added to (1); and (3) choosing the time series of greenhouse gas concentrations.

28 29 7.4.5.2 Physical Mechanisms Linking Cosmic Rays to Cloudiness 30 31 The most widely studied mechanism proposed to explain the possible link between GCR and cloudiness is 32 the «ion - aerosol clear air» mechanism, in which atmospheric ions produced by GCR facilitate aerosol 33 nucleation and growth ultimately impacting CCN concentrations and cloud properties (Carslaw et al., 2002; 34 Usoskin and Kovaltsov, 2008).

The most widely studied mechanism proposed to explain the possible link between GCR and cloudiness is the «ion - aerosol clear air» mechanism, in which atmospheric ions produced by GCR facilitate aerosol nucleation and growth ultimately impacting CCN concentrations and cloud properties (Carslaw et al., 2002; http://www.sciencemag.org/content/298/5599/1732.abstract

Most CM experiments based on RCPs will be driven by greenhouse gas concentrations (Hibbard et al. 2007).8 Furthermore, many Earth system models do not contain a full atmospheric chemistry model, and thus require exogenous inputs of three - dimensional distributions for reactive gases, oxidant fields, and aerosol loadings.

As expected aerosol mass concentration was dominated by desert dust in coarse mode.

Unfortunately it's a complicated picture, as clouds are not only influenced by climatic factors like temperature and evaporation, but also by concentrations of condensation nuclei — aerosols indeed.

«An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 ° K.»

The cloud condensation nuclei counter measures the concentration of aerosol particles by drawing an air sample through a column with thermodynamically unstable supersaturated water vapor that can condense onto aerosol particles.

Sulfate aerosols wash out pretty quickly, so their current atmospheric concentration (and the resulting negative forcing) is mainly determined by the current emissions levels.

However, if one converts the total effects of all greenhouse gases, aerosols, etc. into an equivalent increase in CO2 concentration (by reference to their effective radiative forcing RF, that from a doubling of CO2 being F2xCO2), then what you suggest would be pretty much in line with the generic definition of TCR in Section 10.8.1 of AR5 WGI:

NecktopPC From the abstract for the Rassol and Schneider paper from 1971: «An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 ° K.

Because of the first of these reasons, were we to abruptly halt all emissions now, the sulfate aerosols would rapidly be removed from the atmosphere by precipitation whereas the CO2 concentration would remain elevated, and so there would be a significant further warming influence just as a result of past emissions; this warming would lead to the quite significant global warming that Lindzen mentions.

Aerosols have both natural and human sources, so if we just assume aerosol concentration variation in the atmosphere will continue as it has for the last 165 years, then future AGW can be projected with TCR (1 + beta) where beta is the historical fraction of CO2 radiative forcing caused by all other GHG and aAerosols have both natural and human sources, so if we just assume aerosol concentration variation in the atmosphere will continue as it has for the last 165 years, then future AGW can be projected with TCR (1 + beta) where beta is the historical fraction of CO2 radiative forcing caused by all other GHG and aerosolsaerosols.

An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 deg.K.

Given bounds on volcanic / aerosols, solar, and GHG concentrations, some completely unknown cause is needed for the MWP to have been as warm as now... That is, at least by eyeball, the higher edges of M&W's MWP uncertainty ranges either require throwing out a lot of data or maybe bending conservation of energy.

The annual average is about 0.25 of the peak — but you expect as well that the reflected SW would not vary as much as you suggest albedo of oceans being influenced by «solar zenith angle, wind speed, transmission by atmospheric cloud / aerosol, and ocean chlorophyll concentration.»

«Measurements at a sea platform show that the ocean surface albedo is highly variable and is sensitive to four physical parameters: solar zenith angle, wind speed, transmission by atmospheric cloud / aerosol, and ocean chlorophyll concentration.»

In other words: Proposed strategies to alter the amount of sunlight hitting the Earth's surface by (for example) deliberately injecting millions of tons of sulfate aerosols into the stratosphere pose enormous risks and uncertainties and don «t address the underlying causes of global warming or other major risks from rising concentrations of carbon dioxide, such as ocean acidification.

This thinning, which can decrease the ozone concentration by as much as 70 percent, was caused by the rampant use of human - made chlorofluorocarbons (CFCs), organic compounds that were once widely used in cooling systems and aerosols.

During a dry winter, the reduction of aerosol concentrations in weekend days may overwhelmingly impact on the DTR through a direct effect, i.e. by increasing total solar irradiance near the surface and raising the daytime temperature and maximum temperature, and lowering relative humidity.

About aerosols, one thing to consider is that any natural background concentration of dust etc will not be forcings, by definition, we need to look only at changes.

Cloud formation is affected by several factors, including concentration of aerosols and dust, and are relatively scarce over areas of maximum warming, namely the poles and the deserts.

The 2007 Fourth Assessment Report compiled by the IPCC (AR4) noted that «changes in atmospheric concentrations of greenhouse gases and aerosols, land cover and solar radiation alter the energy balance of the climate system», and concluded that «increases in anthropogenic greenhouse gas concentrations is very likely to have caused most of the increases in global average temperatures since the mid-20th century».

In the thread on Confidence in Radiative Transfer Models, we argued that line - by - line radiative transfer codes and the best band models can accurately simulate clear sky (no clouds, aerosols) infrared radiation fluxes at the surface provided that the vertical profiles of atmospheric temperature and trace gas concentrations are specified accurately.