Sentences with phrase «on aerosol radiative»

What is missing is the more quantitative information on aerosol radiative properties, geographical distributions, trends, and observational results (including uncertainties) that can be found in the IPCC AR4 Report.

Not exact matches

Sally, who was nominated by Dr. Beat Schmid, Associate Director, Atmospheric Sciences and Global Change Division, was honored for her exceptional contribution in the field of atmospheric science, particularly in her efforts to improve understanding of the radiative effect of clouds and aerosols on the Earth's atmosphere and their representation in climate models.

In addition, researchers calculated the changes in the shortwave and longwave and net radiation between the pre-industrial simulation and the present - day simulations to estimate the radiative forcing resulting from the aerosol effects on cirrus clouds.

Stratospheric heating by potential geoengineering aerosols Geoengineering aerosols change stratospheric radiative heating rates Heating rates depend on aerosol species and size

The top priorities should be reducing uncertainties in climate sensitivity, getting a better understanding of the effect of climate change on atmospheric circulation (critical for understanding of regional climate change, changes in extremes) and reducing uncertainties in radiative forcing — particularly those associated with aerosols.

Ice sheet albedo forcing is estimated to have caused a global mean forcing of about — 3.2 W m — 2 (based on a range of several LGM simulations) and radiative forcing from increased atmospheric aerosols (primarily dust and vegetation) is estimated to have been about — 1 W m — 2 each.

As long as the temporal pattern of variation in aerosol forcing is approximately correct, the need to achieve a reasonable fit to the temporal variation in global mean temperature and the difference between Northern and Southern Hemisphere temperatures can provide a useful constraint on the net aerosol radiative forcing (as demonstrated, e.g., by Harvey and Kaufmann, 2002; Stott et al., 2006c).

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

The global mean aerosol radiative forcing caused by the ship emissions ranges from -12.5 to -23 mW / m ^ 2, depending on whether the mixing between black carbon and sulfate is included in the model.

First, for changing just CO2 forcing (or CH4, etc, or for a non-GHE forcing, such as a change in incident solar radiation, volcanic aerosols, etc.), there will be other GHE radiative «forcings» (feedbacks, though in the context of measuring their radiative effect, they can be described as having radiative forcings of x W / m2 per change in surface T), such as water vapor feedback, LW cloud feedback, and also, because GHE depends on the vertical temperature distribution, the lapse rate feedback (this generally refers to the tropospheric lapse rate, though changes in the position of the tropopause and changes in the stratospheric temperature could also be considered lapse - rate feedbacks for forcing at TOA; forcing at the tropopause with stratospheric adjustment takes some of that into account; sensitivity to forcing at the tropopause with stratospheric adjustment will generally be different from sensitivity to forcing without stratospheric adjustment and both will generally be different from forcing at TOA before stratospheric adjustment; forcing at TOA after stratospehric adjustment is identical to forcing at the tropopause after stratospheric adjustment).

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).

To evaluate the global effects of aerosols on the direct radiative balance, tropospheric chemistry, and cloud properties of the earth's atmosphere requires high - precision remote sensing that is sensitive to the aerosol optical thickness, size istribution, refractive index, and number density.

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 radiative forcing of assuming different values for indirect aerosol forcing.

DK12 compounded their erroneous analysis by attempting to calculate the net climate feedback based solely on their estimated 2002 - 2008 OHC increase for the uppermost 700 meters, and only considering the CO2 and solar radiative forcings, ignoring the significant aerosol forcing, for example.

There are lots of experts on small subsets of all the physics that go into climate, radiative physics, clouds, aerosol, oceans, multi-decadal oscillations, solar, global ice, etc..

The effect of anthropogenic black carbon (BC) aerosol on snow is of enduring interest due to its role in aerosol radiative forcing and further consequences for Arctic and global climate change.

That is appropriate since it is the radiative forcing produced by aerosols, ozone etc. in the recent climate state, not in the 1850 climate state, that determines their effect on recent temperatures.

I may have to re-read the Wild paper and again look exactly for what I failed to find the first time: local temperature observations on the surface matching the expected effects of the aerosol radiative forcings the paper does talk a lot about.

In response to the finding that anthropogenic aerosols create a significant perturbation in the earth's radiative balance on regional scales, ESRL / GMD expanded its aerosol research program (1992) to include aerosol monitoring stations in regions where significant aerosol forcing was expected.

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.

This suggests that temperature in these CMIP5 models may be too sensitive to perturbations in radiative forcing, although this depends on the actual magnitude of the anthropogenic aerosol forcing in the modern period.

He thought that this connection might occur via the effect of cosmic ray induced ionization on aerosol and cloud condensation nuclei and thus on the radiative properties of clouds.

The current focus of the program is aerosol radiative forcing of climate: aerosol formation and evolution and aerosol properties that affect direct and indirect influences on climate and climate change.»

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).

Aerosols not only affect the radiative balance at the top of the atmosphere but also exert a forcing on the hydrological cycle (e.g., Ramanathan et al., 2001a).

Incorporating new findings on the radiative forcing of black carbon (BC) aerosols, the magnitude of the climate sensitivity, and the strength of the climate / carbon cycle feedbacks into a simple upwelling diffusion / energy balance model similar to the one that was used in the TAR, we find that the range of projected warming for the 1990 - 2100 period is reduced to 1.1 - 2.8 °C.

Considering the surface radiative forcing may enable quantification of the effects of aerosols on the surface

effects of aerosols on cloud properties (including cloud fraction, cloud microphysical parameters, and precipitation efficiency), which may modify the hydrological cycle without significant radiative impacts;

The probabilistic analyses of DAI reported in this section draw substantially on (subjective) Bayesian probabilities to describe key uncertainties in the climate system, such as climate sensitivity, the rate of oceanic heat uptake, current radiative forcing, and indirect aerosol forcing.

CO; 2 Observations of the Infrared Radiative Properties of the Ocean «[I] t is necessary to understand the physical variables contributing to sea surface emitted and reflected radiation to space.The emissivity of the ocean surface varies with view angle and sea state, the reflection of sky radiation also depends on view angle and sea state, and the absorption of atmospheric constituents such as water vapor, aerosols, and subdivisible clouds affect transmittance.»

Additional variables also being measured by Aqua include radiative energy fluxes, aerosols, vegetation cover on the land, phytoplankton and dissolved organic matter in the oceans, and air, land, and water temperatures.

2) The effects of clouds and aerosols on radiative heat transfer, which are many and varied and still being studied with many questions open.

But even if this is a result of the GISS model, this largely depends on the assumptions made in the model for e.g. amounts and radiative effect of aerosols, which are far from settled.

By 1994, with work on SAR progressing, the Special Report on Radiative Forcing (IPCC, 1995) reported significant breakthroughs in a set of chapters limited to assessment of the carbon cycle, atmospheric chemistry, aerosols and RF.

The SAR, under Bert Bolin (IPCC Chair) and John Houghton and Gylvan Meira Filho (WGI Co-chairs), was planned with and coupled to a preliminary Special Report (IPCC, 1995) that contained intensive chapters on the carbon cycle, atmospheric chemistry, aerosols and radiative forcing.

Radiative forcing is a way to quantify an energy imbalance imposed on the climate system either externally (e.g., solar energy output or volcanic emissions) or by human activities (e.g., deliberate land modification or emissions of greenhouse gases, aerosols, and their precursors).

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.

On aerosols, I am particularly keen to learn more about the possibility to selectively scatter out UV, something that would have large benefits on top of compensating for the radiative forcing of COOn aerosols, I am particularly keen to learn more about the possibility to selectively scatter out UV, something that would have large benefits on top of compensating for the radiative forcing of COon top of compensating for the radiative forcing of CO2.

Here luck was on Broecker's side: the warming by other greenhouse gases and the cooling by aerosols largely cancel today, so considering only CO2 leads to almost the same radiative forcing as considering all anthropogenic effects on climate (see IPCC AR4, Fig.

But a reminder, you are doing V&V on the dynamic core, the bottom boundary conditions (like orography), each individual parameterization (e.g. radiative transfer, convection, boundary layer, clouds, etc), and in the case of coupled models the ocean module, the sea ice module, the land process module, the aerosol module (and in future the ice sheet module), in stand alone mode as well as when coupled in the climate model.

Emissions scenarios were converted to projections of atmospheric GHG and aerosol concentrations, radiative forcing of the climate, effects on regional climate, and climatic effects on global sea level (IPCC, 2001a).

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 acRadiative 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 acradiative 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.

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.

Appendix II gives, in tabulated form, the values for emissions, abundances and burdens, and, radiative forcing of major greenhouse gases and aerosols based on the SRES1 scenarios (Naki» cenovi» c et.