Sentences with phrase «negative radiative forcing»

One important implication of this varying pattern of SO2 emissions is that the historically important, but uncertain negative radiative forcing of sulfate aerosols may decline in the very long run.

While the baroclinic systems are efficient in transporting heat, the enormous negative radiative forcing (Fig. 2) associated with these cloud systems seems to undo the poleward transport of heat by the dynamics.

These aerosols reflected incoming sunlight, causing a negative radiative forcing of 2.5 Wm - 2.

Observations from earlier periods are limited but suggest an additional negative radiative forcing of about — 0.1 watt per square meter from 1960 to 1990.

This negative radiative forcing competes with the greenhouse gas warming for determining the change in evaporation and precipitation.

A positive radiative forcing tends on average to warm the earth's surface; a negative radiative forcing on average tends to cool the earth's surface.

Radiative forcing is a measure of the change in boundary conditions, to which the climate system responds by either warming (in the case of positive radiative forcing; more energy coming in than going out) or cooling (negative radiative forcing).

Our results show that repeated clusters of volcanic eruptions can induce a net negative radiative forcing that results in a centennial and global scale cooling trend via a decline in mixed - layer oceanic heat content.

Near - global satellite aerosol data imply a negative radiative forcing due to stratospheric aerosol changes over this period of about — 0.1 watt per square meter, reducing the recent global warming that would otherwise have occurred.

The authors give some hint when they write:» This suggests that estimates of the net negative radiative forcing due to the total ACI can also be significantly reduced and its uncertainty range could even include positive values.».

The statement of Sato et al. «'' This suggests that estimates of the net negative radiative forcing due to the total ACI can also be significantly reduced and its uncertainty range could even include positive values.»

It is virtually certain that anthropogenic aerosols produce a net negative radiative forcing (cooling influence) with a greater magnitude in the NH than in the SH.

Observations from earlier periods are limited but suggest an additional negative radiative forcing of about — 0.1 W / m2 from 1960 to 1990.

Near - global satellite aerosol data imply a negative radiative forcing due to stratospheric aerosol changes over this period of about — 0.1 W / m2, reducing the recent global warming that would otherwise have occurred.

Not exact matches

First the radiative forcing of clouds is not just in the short wave, and depending on where they are, that can either be positive or negative.

In other words, the same natural forcings that appear responsible for the modest large - scale cooling of the LIA should have lead to a cooling trend during the 20th century (some warming during the early 20th century arises from a modest apparent increase in solar irradiance at that time, but the increase in explosive volcanism during the late 20th century leads to a net negative 20th century trend in natural radiative forcing).

radiative forcing = RF «=» V0 feedback (including planck response) «=» voltage across resistor = i * R «=» F * T (negative for stable climate) radiative disequilibrium «=» v0 + i * R = voltage across inductor = L * di / dt «=» heating rate = C * dT / dt okay...

The system can have a net negative feedback and still change very much provided a radiative forcing from sunlight or CO2 is sufficiently large, although for typical changes in these variables that Earth encounters, one would indeed expect only relatively small climate changes to occur if negative feedbacks did in fact dominate.

(where the trend in net monochromatic flux reverses) before reaching the ultimate saturation; if this situation came up, after each «pseudosaturation», the radiative forcing can still be estimated with a band - widenning effect outside the central region where the last «pseudosaturation» has taken effect, minus the contribution from whatever is happenning in the center (think in terms of positive and negative areas on the graph).

The variation of RF over a layer, increasing / decreasing with height, means that there is a forced convergence / divergence of radiative fluxes; the RF acting on a layer is equal to the difference between RF at the top and bottom of the layer and is positive / negative if the RF is greater / smaller at the top.

In addition, since IPCC tells us that the total net anthropogenic radiative forcing is essentially equal to the radiative forcing from CO2 alone, we can essentially ignore other anthropogenic forcing factors (positive and negative).

By using dual radioactive tracers with differing lifetimes, Wilson et al. [2017] found short term increases in CH4 and CO2 release during periods of thaw in a discontinuous permafrost were generally offset by long - term accumulation of peat in the ensuing millennia, leading the regions to continue to be net carbon sinks with negative atmospheric radiative forcing, given the long life - time of atmospheric CO2.

The radiative forcing is not the same thing as the radiative imbalance, and the numbers aren't at all comparable in this way, since the imbalance decays to zero as the planet gets warmer (even if positive or negative feedbacks dominate).

The argument that negative feedbacks must be dominating simply from the fact that the observed imbalance is «less than the radiative forcing» (~ 1.6 W / m2) is absolutely nonsensical.

If the radiative imbalance is less than the radiative forcing, the radiative feedbacks must be negative.»

Unfortunately for Pielke, the radiative feedback, the way he defines it is usually opposite to forcing, so yes it is negative, and yes it is the well known Planck response that is supposed to be negative otherwise we would all be in trouble.

Humans cause numerous other radiative forcings, both positive (e.g. other greenhouse gases) and negative (e.g. sulfate aerosols which block sunlight).

Fortunately, the negative and positive forcings are roughly equal and cancel each other out, and the natural forcings over the past half century have also been approximately zero (Meehl 2004), so the radiative forcing from CO2 alone gives us a good estimate as to how much we expect to see the Earth's surface temperature change.

This unique feature of the Antarctic atmosphere has been shown to result in a negative greenhouse effect and a negative instantaneous radiative forcing at the top of the atmosphere (RFTOA: INST), when carbon dioxide (CO2) concentrations are increased, and it has been suggested that this effect might play some role in te recent cooling trends observed over East Antarctica.

The rationale advanced for focusing on negative emissions approaches are usually the threat posed by burgeoning emissions, which could result in exceeding of critical climatic thresholds in a few decades, as well as system inertia, which could lock in temperature increases associated with radiative forcing for many centuries.

Most of the moisture is found below about 10,000 feet, so that is where the effect of changes in lapse rate will be felt, and the effect of an increase in moisture is to decrease the near - surface lapse rate, potentially resulting in an important negative feedback on radiative forcing.

My best estimates (guesses, but perhaps better guesses than those of the IPCC because I have no vested interest in the answers) are that the IPCC exaggerates the CO2 radiative forcing (which can not be measured) by around 20 %; that it exaggerates the Planck parameter (which can not be measured) by 20 %; and that it exaggerates the sum of all unamplified feedbacks (which can not be measured) threefold, because, as Lindzen and Choi (2009,, 2011) and Spencer and Braswell (2010, 2011) have demonstrated, feedbacks are somewhat net - negative.

None of the Annan / Hargreaves priors go below zero, and while this may be physically realistic it does not allow for the fact that the observational data generate negative sensitivities, mostly because of ocean cycle warming and cooling effects that the radiative forcing estimates do not take into account.

It is bizarre to suggest that a significant net slowdown of heat loss in the face of the compensating negative forcings of increased convection and the increased outward radiative flow caused by a greater surface to space differential could be induced by mankind's tiny contribution to the CO2 in the atmosphere.

Most likely positive and negative feedbacks roughly cancel each other out, so that actual ECS is around 1.0 to 1.2, the value for the radiative forcing of CO2 by itself.

The forcing by lower stratospheric O3 is an unusual one in that it has a positive short - wave and a negative long - wave radiative forcing.

We do know that added carbon dioxide is the largest human - caused, and black carbon the second largest positive annual, global - averaged radiative forcing, while sulfates are among the largest human - caused negative annual, global - averaged radiative forcing.

However, the climate system is not linear, and if there are significant negative feedbacks to increased radiative forcing, then a significant portion of the recent warming could've been caused by natural variability if the corresponding variability went up with temperature.

To ΔF2xCO2 is added the slightly net - negative sum of all other anthropogenic - era radiativeforcings, calculated from IPCC values (Table 1), to obtain total anthropogenic - era radiative forcing ΔF2x at CO2 doubling (Eqn.

In addition, there must be an altitude at which radiative forcing for 2X CO2 is a maximum, because we know that the forcing is negative in the stratosphere (as well as greater in magnitude).

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.

Earth 2 has experienced a decreased, and in fact negative, radiative forcing during the period of SO2 emissions.