Sentences with phrase «indirect aerosol»

To do so we assume that all anthropogenic forcings except indirect aerosol forcing are given their central values, and consider a range of values for the reference (2005) indirect forcing amount.

The effect on radiative forcing of assuming different values for indirect aerosol forcing.

The bottom three curves show the history of indirect aerosol forcing used in the top three curves.

Why, then, is − 1.8 W / m2 for indirect aerosol forcing highly unlikely?

The top three curves show total anthropogenic forcing assuming central values for all components other than indirect aerosol forcing.

, and impacts on stratospheric ozone, increases in acid rain in polar regions, possible indirect aerosol effects on high cirrus clouds (hopefully other studies in future will better quantify these).

Climate scientist Kevin Trenberth also notes that the change in the estimated aerosol forcing is mainly associated with indirect aerosol effects, but half of GCMs don't include these indirect effects, and those that do actually tend to simulate less warming.

Aerosols may influence climate in several ways: directly through scattering and absorbing radiation, and indirectly by acting as cloud condensation nuclei or modifying the optical properties and lifetime of clouds (see Indirect aerosol effect).

These curves are based on the best - estimate of indirect aerosol forcing in 2005 (− 0.7 W / m2), and on assumed 2005 forcings of − 1.1 and − 1.8 W / m2.

The effect on global - mean temperature of assuming a large value for indirect aerosol forcing (viz. − 1.8 W / m2 in 2005, the 95th percentile value according to the IPCC AR4) compared with temperatures for the central indirect forcing estimate (− 0.7 W / m2) and a less extreme maximum of − 1.1 W / m2.

That results in the data maximum likelihoods for direct and indirect aerosol forcing being in the upper tails of the priors, biasing the aerosol forcing estimation to more negative values (and hence biasing ECS estimation to a higher value).

The (posterior) mean estimated by the study was circa -0.3 W / m ^ 2 for indirect aerosol forcing and -0.4 W / m ^ 2 for direct.

It is not true that Aldrin assumes zero indirect aerosol effects.

The indirect aerosol effect on clouds is non-linear [1], [76] such that it has been suggested that even the modest aerosol amounts added by pre-industrial humans to an otherwise pristine atmosphere may have caused a significant climate forcing [59].

Hence you are right that indirect aerosol effect is important.

Satellite observations do play, however, a key role for evaluating models of the indirect aerosol radiative effect (Ghan et al., 2001b).

Indirect aerosol effect - Aerosols may lead to an indirect radiative forcing of the climate system through acting as cloud condensation nuclei or modifying the optical properties and lifetime of clouds.

Sexton et al. (2003) did find some evidence for a nonlinear interaction between the effects of greenhouse gases and the indirect effect of sulphate aerosols in the atmosphere - only version of HadCM3 forced by observed SSTs; the additional effect of combining greenhouse gases and indirect aerosol effects together was much smaller than each term separately but was found to be comparable to the warming due to increasing tropospheric ozone.

«Tropical Rainfall Trends and the Indirect Aerosol Effect.»

The AR4 range for indirect aerosol forcing is essentially a compromise between observationally based studies (see main text), which invariably give a much lower value for the upper bound (e.g., around − 1 W / m2 in Stott et al. 2006), and estimates derived from forward calculations, which range up to − 4 W / m2 for total sulfate aerosol forcing (Anderson et al. 2003).

We provide evidence that the IPCC estimate for the upper bound of indirect aerosol forcing is almost certainly too high.

If the 95th percentile for indirect aerosol forcing given in the AR4 is so improbable, then we need to produce an improved estimate of the uncertainty in aerosol forcing to use in our probabilistic calculations.

If the indirect aerosol forcing uncertainty is reduced to ± 0.4 W / m2 (i.e., a 90 % range of − 0.3 to − 1.1 W / m2) then the overall aerosol forcing uncertainty (i.e., the 90 % confidence interval) is reduced to ± 0.57 W / m2.

With regards to the Otto paper at least, (or in the calculation I showed above), aerosol estimates come from IPCC AR5 which includes expert assessment of both direct and indirect aerosol forcing and for the industrial period is about -0.45 W / m ^ 2 each.

«Here, it is sufficient to note that many of the 20CEN / A1B simulations neglect negative forcings arising from stratospheric ozone depletion, volcanic dust, and indirect aerosol effects on clouds... It is likely that omission of these negative forcings contributes to the positive bias in the model average TLT trends in Figure 6F.