Sentences with phrase «of aerosol indirect effect»

Menon, S., A.D. Del Genio, D. Koch, and G. Tselioudis, 2002: GCM simulations of the aerosol indirect effect: Sensitivity to cloud parameterization and aerosol burden.

adding two variables that were requested in the ACCMIP Word document but not explained in the spreadsheet: the longwave and the shortwave cloud radiative forcing with reference (fixed) composition, for diagnosis of aerosol indirect effect.

They are therefore unaffected by a re-evaluation of the aerosol indirect effect.

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.

It is inconsistent to talk in one breath about the importance of aerosol indirect effects and solar indirect effects and then state that «simple models» are going to do the trick.

Not exact matches

An adjustment is necessary because as climate models are continually evaluated against observations evidence has become emerged that the strength of their aerosol - cloud interactions are too strong (i.e. the models» «aerosol indirect effect» is larger than inferred from observations).

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

He has pioneered the use of SP - CAM to study aerosol - cloud interaction and used it together with satellite observations to constrain aerosol indirect effects.

Aldrin et al produce a number of (explicitly Bayesian) estimates, their «main» one with a range of 1.2 ºC to 3.5 ºC (mean 2.0 ºC) which assumes exactly zero indirect aerosol effects, and possibly a more realistic sensitivity test including a small Aerosol Indirect Effect of 1.2 - 4.8 ºC (mean indirect aerosol effects, and possibly a more realistic sensitivity test including a small Aerosol Indirect Effect of 1.2 - 4.8 ºC (mean 2aerosol effects, and possibly a more realistic sensitivity test including a small Aerosol Indirect Effect of 1.2 - 4.8 ºC (mean 2Aerosol Indirect Effect of 1.2 - 4.8 ºC (mean Indirect Effect of 1.2 - 4.8 ºC (mean 2.5 ºC).

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).

It is rather surprising that adding cloud lifetime effect forcing makes any difference, insofar as Aldrin is estimating indirect and direct aerosol forcings as part of his Bayesian procedure.

The total of -0.7 W / m ^ 2 is the same as the best observational (satellite) total aerosol adjusted forcing estimate given in the leaked Second Order Draft of AR5 WG1, which includes cloud lifetime (2nd indirect) and other effects.

When Aldrin adds a fixed cloud lifetime effect of -0.25 W / m ^ 2 forcing on top of his variable parameter direct and (1st) indirect aerosol forcing, the mode of the sensitivity PDF increases from 1.6 to 1.8.

Earth's measured energy imbalance has been used to infer the climate forcing by aerosols, with two independent analyses yielding a forcing in the past decade of about − 1.5 W / m2 [64], [72], including the direct aerosol forcing and indirect effects via induced cloud changes.

However, I am not optimistic — the specifics of the small scale physics (aerosol indirect effects on clouds, sea ice formation, soil hydrology etc.) are so heterogeneous that I don't see how you can do without calculating the details.

Additionally there is a huge amount of uncertainty in aerosol - cloud effects (the «aerosol indirect effect»).

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.

There are indeed uncertainties in aerosol forcing (not just the indirect effects) and, especially in the earlier part of the 20th Century, uncertainties in solar trends and impacts.

c) anthropogenic aerosols — mainly sulfate and nitrate (from emissions of SO2 and NOx / NH3) have a strong direct effect and undoubted liquid cloud nucleation impacts (the indirect effects).

Probably not the most relevant one, though, given that the main point of the Shindell et al paper was methane's indirect effect on aerosols.

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).

Therefore when you ask about the general effects of cloud feedbacks on climate, you have moved well beyond the scope of a discussion about aerosol second indirect effects.

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.

The final candidates are numerous interactions of aerosols with clouds, the so - called «indirect effects».

While this is indeed very interesting and does suggest that aerosol indirect effects can have important climatic consequences, it is merely the first step to attributing any particular climatic effect (failure of Sahel monsoon) to a particular cause (aerosol indirect effects).

If Dr Schmidt had actually seen the film (which I doubt) he would realize that this is part of a short bridging sequence which acts as a «trailer» of material which will be treated more fully later in the film (the immediately following sequence explains the «indirect aerosol effect», in fact).

Still there remains a question in my mind about the relative importance of the GHG warming and the aerosol indirect effects on «global dimming».

The bottom line is that uncertainties in the physics of aerosol effects (warming from black carbon, cooling from sulphates and nitrates, indirect effects on clouds, indirect effects on snow and ice albedo) and in the historical distributions, are really large (as acknowledged above).

Thus the balance is that soot has more positive effect than the combined direct and indirect negative effects of sulphate (and other) aerosols.

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.

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.

The top panel shows the direct effects of the individual components, while the second panel attributes various indirect factors (associated with atmospheric chemistry, aerosol cloud interactions and albedo effects) and includes a model estimate of the «efficacy» of the forcing that depends on its spatial distribution.

In the context of IPCC, it is known as «indirect effect of aerosols.»

This assessment is from my own lab and so I may be a little biased, but although there are significant uncertainties (particular for the aerosol indirect effects), it probably gives a reasonable idea of the current thinking.

Geophysical Fluid Dynamics Laboratory general circulation model investigation of the indirect radiative effects of anthropogenic sulfate aerosol Journal of Geophysical Resarach, 2005

Some of these forcings are well known and understood (such as the well - mixed greenhouse gases, or recent volcanic effects), while others have an uncertain magnitude (solar), and / or uncertain distributions in space and time (aerosols, tropospheric ozone etc.), or uncertain physics (land use change, aerosol indirect effects etc.).

8 - 58): either (i) the IPCC calculation doesn't include the indirect effects of methane on the oxidation of SO2 to sulfur aerosols or (ii) the effects are included, but subsequent research found a smaller effect.

Assuming a Northern Hemisphere to Southern Hemisphere ratio of 2:1 for the aerosol indirect effect, this would imply a globally - averaged forcing of -1.5 Wm - 2.

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 ofIndirect 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 ofindirect radiative forcing of the climate system through acting as cloud condensation nuclei or modifying the optical properties and lifetime of clouds.

The direct and indirect radiative effects of biogenic secondary organic aerosol.

This was shown to be the case for near - surface temperatures in the PCM (Meehl et al., 2004), in the Hadley Centre Climate Model version 2 (HadCM2; Gillett et al., 2004c) and in the GFDL CM2.1 (see Table 8.1) model (Knutson et al., 2006), although none of these studies considered the indirect effects of sulphate aerosols.

In models that include indirect effects, different treatments of the indirect effect are used, including changing the albedo of clouds according to an off - line calculation (e.g., Tett et al., 2002) and a fully interactive treatment of the effects of aerosols on clouds (e.g., Stott et al., 2006b).

In addition, some models include the indirect effects of tropospheric sulphate aerosols on clouds (e.g., Tett et al., 2002), whereas others consider only the direct radiative effect (e.g., Meehl et al., 2004).

Given our very short and spotty data on the relative abundance (or importance) of the majority of these aerosols, and given our very poor understanding of the direct, indirect, and side effects of the majority of these aerosols, any numbers that anyone generates about their abundance, importance, or total radiative forcing are going to be a SWAG.

«Chiefly the burning of fossil fuels», not CO2, just burning of fossil fuels, so black carbon, indirect aerosol effects, land use anything that involves the burning of fossil fuels.

A few days ago a paper (Sato et al) dealing with some aspects of the «Aerosol Cloud Interactions», (ACI, also called «aerosol indirect effects») was reAerosol Cloud Interactions», (ACI, also called «aerosol indirect effects») was reaerosol indirect effects») was released.

Constraining the influence of natural variability to improve estimates of global aerosol indirect effects in a nudged version of the Community Atmosphere Model 5.

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.

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