Sentences with phrase «estimates of albedo»

We can make good estimates of global temperature so can estimate planck radiation (on global level), good estimates of albedo from ice extent, reasonable estimates of evaporation and convection from temperature contraints, now try closing that surface budget with GHG.

The ISCCP group produces an independent estimate of the albedo, from performing a full radiative flux calculation that takes into account observations of all radiative forcings and produces top of the atmosphere, surface, and in - atmosphere fluxes (data, figure right).

Not exact matches

The retreat of sea ice in the Arctic Ocean is diminishing Earth's albedo, or reflectivity, by an amount considerably larger than previously estimated, according to a new study that uses data from instruments that fly aboard several NASA satellites.

«note that what is done with these estimates of climate sensitivity for LGM climate is to use the state of the climate already in place at the LGM — including the ice albedo.»

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.

This estimate is generous to the GCR hypothesis, since the cumulus - to - water albedo shift exaggerates the true change of low clouds, and I need bond albedos in my calculation and I'm using visible albedos.

MISR can provide some discrimination in special cases (picking out dust via a retrieval of non-spherical particles, or using the single scattering albedo to distinguish black carbon), but overall the estimates mix up sulphates, dust, black carbon, sea salt, nitrates and secondary organics.

This was a relatively stable climate (for several thousand years, 20,000 years ago), and a period where we have reasonable estimates of the radiative forcing (albedo changes from ice sheets and vegetation changes, greenhouse gas concentrations (derived from ice cores) and an increase in the atmospheric dust load) and temperature changes.

«Our estimate for the mean soot effect on spectrally integrated albedos in the Arctic (1.5 %) and Northern Hemisphere land areas (3 %) yields a Northern Hemisphere forcing of 0.3 W m2 or an effective hemispheric forcing of 0.6 W m2.»

In Hansen Nazarenko 2004, Hansen wrote that «Our estimate for the mean soot effect on spectrally integrated albedos in the Arctic... is about one quarter of observed global warming.»

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.

They estimate that increasing the reflectance — commonly known as albedo — of every urban area by 0.1 will give a CO2 offset between 130 and 150 billion tonnes.

Estimating the cloudy sky albedo of sea ice and snow from space.

Cloud albedo results in reflection of around 14 % of the incoming SW radiation, resulting in cooling estimated to be 48 W / m ^ 2.

The albedo change resulting from the snowline retreat on land is similarly large as the retreat of sea ice, so the combined impact could be well over 2 W / sq m. To put this in context, albedo changes in the Arctic alone could more than double the net radiative forcing resulting from the emissions caused by all people of the world, estimated by the IPCC to be 1.6 W / sq m in 2007 and 2.29 W / sq m in 2013.»

This estimate was refined by Hansen and Nazarenko (2004), who used measured BC concentrations within snow and ice at a wide range of geographic locations to deduce the perturbation to the surface and planetary albedo, deriving an RF of +0.15 W mâ $ «2.

The real «flat plate» GHE is between 11 and 17 K depending on your estimate of present albedo and planetary emissivity in the absence of GHGs.

Based on the insolation received by the Earth, allowing for its estimated albedo and some internal core heat, the blackbody temperature of the Earth is 254.3 K -LRB--18.8 °C).

If the Earth's true emission temperature (which occurs somewhere at altitude in the troposphere) is less than the 255 K predicted by theory (assuming an albedo 0.306), then the Planck parameter may well be considerably less than the IPCC's value, in which event on this ground alone climate sensitivity may be well below its central estimate of 3.26 K per CO2 doubling.

These new, spectral, simultaneous remote and in situ observations suggest that the single scattering albedo (ωo) of pure dust at a wavelength of 0.67 µm is predominantly in the range 0.90 to 0.99, with a central global estimate of 0.96.

I thought the paleo - climate based estimates of climate sensitivity actually were accounting for the global ice albedo part of state dependency.

«his refusal to calculate a total year energy balance» - At this stage, no such calculation can be made, because I have calculated in detail only the changes in the incoming energy (the insolation) as a function of time - of - year and latitude; I have estimated also the effect upon the insolation absorption through a change in the Arctic albedo.

The estimates — based on analysis of fire's impact on emissions of carbon dioxide, nitrous oxide, and methane; albedo or the reflectivity of Earth's surface; and release of aerosols and other particulates — suggest fire plays a major large role in climate than conventionally believed.

The problem with sensitivity estimates based on ancient data is the great uncertainty of the input data (solar activity, land albedo, etc), which creates very fuzzy numbers.

The albedo is assumed to be 30 % of the estimated 342watts / m ^ 2 of solar flux averaged over tyhe Earth surface which is 102.6 watts / m ^ 2.

There is consistence [70] between the estimates of the ISCCP, the global albedo, the insolation measured at the surface and the length of the daily insolation observed in many places: all of them are likely to explain the temperature changes.

-- Incorporation of more aerosol species and improved treatment of aerosol - cloud interactions allow a best estimate of the cloud albedo effect.

I've only found TWO numerical estimates of the Ice Albedo forcing in the ice ages.

The wide range of estimates of climate sensitivity is attributable to uncertainties about the magnitude of climate feedbacks (e.g., water vapor, clouds, and albedo).

Using feedback parameters from Fig. 8.14, it can be estimated that in the presence of water vapor, lapse rate and surface albedo feedbacks, but in the absence of cloud feedbacks, current GCMs would predict a climate sensitivity (± 1 standard deviation) of roughly 1.9 °C ± 0.15 °C (ignoring spread from radiative forcing differences).

The great thing is that, since we can make good estimates of the changes in solar radiation, changes in the Earth's albedo due to melting ice, and changes in atmospheric CO2 concentration during the ice ages, scientists can directly calculate the sensitivity of the climate to changes in the atmospheric CO2 concentration.

The three studies, using different methodologies to estimate the global surface albedo feedback associated with snow and sea ice changes, all suggest that this feedback is positive in all the models, and that its range is much smaller than that of cloud feedbacks.

You have exaggerated the error ranges in the albedo by looking at the separate estimates of land and ocean albedo.

Variability of biomass burning aerosol optical characteristics in southern Africa during the SAFARI 2000 dry season campaign and a comparison of single scattering albedo estimates from radiometric measurements.

Estimates of the Earth's average albedo vary in the range 0.3 — 0.4, resulting in different estimated effective temperatures.

This is exactly the figure I gave you of 30 % to 40 % for estimated average albedo.

Anthropogenic forcing (human - caused warming due to land use changes that reduces albedo and burnign of fossil fuels that raises CO2 levels, etc.) is most proabably below the lower IPCC estimate of 0.6 W / m ^ 2.

Yet measured variations in earth's albedo over just several years has it changing by more watts / m2 than the highest estimate of alleged anthropogenic warming.

says «the ISCCP estimate shows a decreasing albedo trend of 1 - 2 % in the 80s and 90s».

The albedo of the Earth System, including the reflectivity of clouds and of the surface is estimated to be 70 % 30 % by many experts.

For the global albedo, the table that you have quoted from shows four estimates in the range of 31 to 31.3 % and two outlier estimates of 28.1 % and 33.8 %.

The ISCCP estimate (right) shows a decreasing albedo trend of 1 - 2 % in the 80s and 90s (as opposed to 7 - 8 % in the earthshine - based proxy), a small increase of 1 % form 1999 to 2001 and a flattening of the curve in the last three years.

A reasonable estimate of the forcings is 6.6 + / -1.5 W / m2 (roughly half from albedo changes, slightly less than half from greenhouse gases - CO2, CH4, N2O).

Dropping LU forcing as a regressor does not increase the residual standard deviation of 0.00195, but brings the estimated coefficients for Aerosol + Ozone and for Snow Albedo BC down to somewhat closer to one.

This is completely unrealistic, because we've got other ways to estimate climate sensitivity, notably the temperature and albedo, dust, greenhouse gas induced forcings of the last ice age, and those independently make it quite hard for sensitivity to be less than 1.5 C or more than 4.5 C.

Estimating the Global Radiative Impact of the Sea - Ice - Albedo Feedback in the Arctic..

Albedo level varies more from year to year creating an energy variation that likely exceeds the estimated impact of human CO2.

Another way of saying this is to estimate ECS from the last glacial - interglacial transition, the albedo change due to ice sheet melting is taken as a forcing rather than as a feedback.