Sentences with phrase «aerosol indirect effect on»

Several observational studies (see Chapter 5) support the existence of the first aerosol indirect effect on low - level clouds and a negative sign for the associated radiative forcing, but these studies do not give indications on what a (negative) upper bound of the forcing would be.

«We found that aerosol indirect effect on deep convective cloud systems could lead to enhanced regional convergence and a strong top - of - atmosphere warming.»

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.

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

But including aerosol indirect effects on radiative forcing has made it easier to generate a greater variety of 20th century simulations without affecting other aspects of the climate simulation as strongly.

When aerosol indirect effects on cloud cover were included, tropospheric (anthropogenic) aerosol efficacy reduced from 1.14 to 0.99.

Not exact matches

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

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.

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].

There is a large literature on indirect aerosols effects, and in particular, those associated with ship tracks.

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.

Solar activity impacts on climate are a fascinating topic, and encompass direct radiative processes, indirect effects via atmospheric chemistry and (potentially) aerosol formation effects.

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.

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.

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.

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).

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.

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.

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.

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.

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.

(Note: the biggest issue is climate sensitivity, with a secondary issue being the magnitude of modes of natural internal variability on multi-decadal time scales, and tertiary issues associated model inadequacies in dealing with aerosol - cloud processes and solar indirect effects.)

In our study, the biggest aerosol effect on climate came from the effect of aerosol - cloud indirect effect.

«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.

The experiments were performed with ModelE2, a new version of the NASA Goddard Institute for Space Sciences (GISS) coupled general circulation model that includes three different versions for the atmospheric composition components: a noninteractive version (NINT) with prescribed composition and a tuned aerosol indirect effect (AIE), the TCAD version with fully interactive aerosols, whole - atmosphere chemistry, and the tuned AIE, and the TCADI version which further includes a parameterized first indirect aerosol effect on clouds.

My impression is that it is the advent of models incorporating indirect aerosol effects — the effects aerosols have on climate through their modification of clouds — that has really brought this question to the forefront.

This review paper outlines the rationale for long - term monitoring of the global distribution of natural and anthropogenic aerosols and clouds with specificity, accuracy, and coverage necessary for a reliable quantification of the direct and indirect aerosol effects on climate.

However, model complexity is necessary to quantify the anthropogenic impact on climate via the aerosol direct and indirect effects.

However, the total influence on monsoon precipitation of temporally varying direct and indirect effects of various aerosol species is still not resolved and the subject of active research.

Aerosol collections on the NOAA Ron Brown for subsequent processing of INP activation temperature spectra and composition analyses, add a valuable measurement to the ACAPEX and related CalWater2 (NOAA) studies for use in parameterizing and modeling the impacts of marine boundary layer and other aerosols on climate and radiation via aerosol - indirect effects on mixed phase Aerosol collections on the NOAA Ron Brown for subsequent processing of INP activation temperature spectra and composition analyses, add a valuable measurement to the ACAPEX and related CalWater2 (NOAA) studies for use in parameterizing and modeling the impacts of marine boundary layer and other aerosols on climate and radiation via aerosol - indirect effects on mixed phase aerosol - indirect effects on mixed phase clouds.

While it is impossible to know what decisions are made in the development process of each model, it seems plausible that choices are made based on agreement with observations as to what parameterizations are used, what forcing datasets are selected, or whether an uncertain forcing (e.g. mineral dust, land use) or feedback (indirect aerosol effect) is incorporated or not.

Additional runs for 2000 with 1850 climate and for 2030 and 2100 (RCP 8.5) with 2000 emissions are designed to separate the effects of climate change on constituents and for isolating aerosol indirect effects more cleanly using the clear - sky / all - sky flux diagnostics.

Your answer was «Narrowing of uncertainty in the aerosol indirect effect» Has this been a subject of comment on this blog?

On the other hand, if some of the anthropogenic aerosols act as ice nuclei, supercooled clouds could be converted into ice clouds by the glaciation indirect effect (Lohmann, 2002), resulting in more efficient precipitation formation.

Other types of forcing that vary across the ensemble include solar variability, the indirect effects of aerosols on clouds and the effects of land use change on land surface albedo and other land surface properties (Table 10.1).

These agents include tropospheric and stratospheric ozone, all of the non-sulphate aerosols, the indirect effects of aerosols on cloud albedo and lifetime, the effects of land use and solar variability.

Aerosols have a direct and indirect effect on albedo.

The direct and indirect effects of human - related aerosols on radiation, cloud, precipitation, and so on, might play an important role in generating the opposite signal in the weekend effect for different seasons.

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.

The cases for more complex chemical and aerosol effects were becoming clear, but the scientific community was unable at the time to reach general agreement on the existence, scale and magnitude of these indirect effects.

In terms of sulphate aerosols, both the direct radiative effects and the indirect effects on clouds were acknowledged, but the importance of carbonaceous aerosols from fossil fuel and biomass combustion was not recognised (Chapters 2, 7 and 10).

This study will examine the current state of knowledge regarding the direct and indirect radiative forcing effects of gases, aerosols, land use, and solar variability on the climate of the Earth's surface and atmosphere and it will identify research needed to improve our understanding of these effects.

The forcing aspect of the indirect effect at the top of the atmosphere is discussed in Chapter 2, while the processes that involve feedbacks or interactions, like the «cloud lifetime effect» [6], the «semi-direct effect» and aerosol impacts on the large - scale circulation, convection, the biosphere through nutrient supply and the carbon cycle, are discussed here.

The aerosol indirect effects are the greatest source of uncertainty in assessing the human impact on climate change (reviewed here.

There's a large amount of uncertainty about how aerosols affect climate, especially through the indirect effects on clouds.

Topics that I work on or plan to work in the future include studies of: + missing aerosol species and sources, such as the primary oceanic aerosols and their importance on the remote marine atmosphere, the in - cloud and aerosol water aqueous formation of organic aerosols that can lead to brown carbon formation, the primary terrestrial biological particles, and the organic nitrogen + missing aerosol parameterizations, such as the effect of aerosol mixing on cloud condensation nuclei and aerosol absorption, the semi-volatility of primary organic aerosols, the importance of in - canopy processes on natural terrestrial aerosol and aerosol precursor sources, and the mineral dust iron solubility and bioavailability + the change of aerosol burden and its spatiotemporal distribution, especially with regard to its role and importance on gas - phase chemistry via photolysis rates changes and heterogeneous reactions in the atmosphere, as well as their effect on key gas - phase species like ozone + the physical and optical properties of aerosols, which affect aerosol transport, lifetime, and light scattering and absorption, with the latter being very sensitive to the vertical distribution of absorbing aerosols + aerosol - cloud interactions, which include cloud activation, the aerosol indirect effect and the impact of clouds on aerosol removal + changes on climate and feedbacks related with all these topics In order to understand the climate system as a whole, improve the aerosol representation in the GISS ModelE2 and contribute to future IPCC climate change assessments and CMIP activities, I am also interested in understanding the importance of natural and anthropogenic aerosol changes in the atmosphere on the terrestrial biosphere, the ocean and climate.