Sentences with phrase «between aerosol forcing»

I decided to check what GCMs say about the relationship between aerosol forcing and response by comparing latitudinal temperature change difference between HistoricalGHG and Historical all - forcing runs.

In CMIP5 there is no correlation between aerosol forcing and sensitivity across the ensemble, so the implication that aerosol forcing affects the climate sensitivity in such «forward» calculations is false... The spread of model climate sensitivities is completely independent of historical simulations.»

They find that the correlation between aerosol forcing and ECS changes sign between CMIP3 and CMIP5 (also Andrews et al).

In CMIP5 there is no correlation between aerosol forcing and sensitivity across the ensemble, so the implication that aerosol forcing affects the climate sensitivity in such «forward» calculations is false.»

The relationship between aerosol forcing and ECS is roughly linear.

Hegerl: [IPCC AR5 models] So using the 20th c for tuning is just doing what some people have long suspected us of doing -LSB-...] and what the nonpublished diagram from NCAR showing correlation between aerosol forcing and sensitivity also suggested.

But questions remained concerning the degree of decadal variability, the length of the record and the balance in the models between aerosol forcing and climate sensitivity (which can't really be disentangled using this measure).

However, the fundamental point which underlies all their calculations is the link between aerosol forcing and sensitivity, which I would argue is not as strong as they have posited.

Hansen for example suggested (at the AGU in dec 2008) that climate sensitivity is known more accurately than the other two quantities, whereas the more often heard trade - off (correct me if I'm wrong) is between aerosol forcing and sensitivity.

Not exact matches

The researchers [3] quantified China's current contribution to global «radiative forcing» (the imbalance, of human origin, of our planet's radiation budget), by differentiating between the contributions of long - life greenhouse gases, the ozone and its precursors, as well as aerosols.

The hemispheric responses, in particular in the SH where the imposed aerosol forcing is very small, can be quite sensitive to factors such as how a given model transports heat between the hemispheres, however.

There is a huge offset between aerosols and CO2 sensitivity, as can be seen in Climate sensitivity and aerosol forcings.

They, too, assume an equivalence in radiative forcing between GHG and aerosol, What they do is add different estimates of the aerosol radiative forcing to the GHG forcing, while keeping the temperature response fixed at the observed recent warming.

Ferdinand: The Boer & Yu, 2003 paper shows that the correlation between the pattern of aerosol forcing and the pattern of temperature response has only 20 % covariance, and that the covariance of the response to GHG and aerosol forcing is > 60 %.

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.

You can also see the relative uncertainty between forcings (e.g., it is much larger for aerosols than for GHGs).

Note that while results from fingerprint detection approaches will be affected by uncertainty in separation between greenhouse gas and aerosol forcing, the resulting uncertainty in estimates of the near - surface temperature response to greenhouse gas forcing is relatively small (Sections 9.2.3 and 9.4.1.4).

These results typically provide a somewhat smaller upper limit for the total aerosol forcing than the estimates given in Chapter 2, which are derived from forward calculations and range between — 2.2 and — 0.5 W m — 2 (5 to 95 % range, median — 1.3 W m — 2).

Some of these studies use the difference between Northern and Southern Hemisphere mean temperature to separate the greenhouse gas and aerosol forcing effects (e.g., Andronova and Schlesinger, 2001; Harvey and Kaufmann, 2002).

The inverse estimates summarised in Table 9.1 suggest that to be consistent with observed warming, the net aerosol forcing over the 20th century should be negative with likely ranges between — 1.7 and — 0.1 W m — 2.

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).

They determine the probability of combinations of climate sensitivity and net aerosol forcing based on the fit between simulations and observations (see Section 9.6 and Supplementary Material, Appendix 9.

Nevertheless, the similarity between results from inverse and forward estimates of aerosol forcing strengthens confidence in estimates of total aerosol forcing, despite remaining uncertainties.

Therefore in a fingerprint study that doesn't distinguish between aerosols and GHGs, what the exact value of the aerosol forcing right is basically irrelevant.

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.

These details are not inconsequential because most of the conclusions in their paper stem from the rapid increase in climate sensitivity between 1.0 and 2.0 W / m2 aerosol forcing.

Given that you comment that the largest differences between the different forcings is between land and ocean or between the Northern and Southern Hemispheres, have you looked at the land — ocean temperature difference or the Northern — Southern Hemisphere temperature difference, as they both scale linearly with ECS, in the same way as global mean temperature for ghg forcing, but not for aerosol forcing.

Ferdinand: The Boer & Yu, 2003 paper shows that the correlation between the pattern of aerosol forcing and the pattern of temperature response has only 20 % covariance, and that the covariance of the response to GHG and aerosol forcing is > 60 %.

But there are offsets between GHGs / aerosol combinations and solar activity (especially as derived by Hoyt and Schatten), which may have been underestimated (see Stott e.a. 2003) If one simply should compare only the influence of solar (by H&S or even LBB) with the increase in heat content of the oceans, one can get a similar conclusion: that solar is the main driving force in ocean heat content.

On your page, you show the results for HADCM3 aerosol and ozone (actually the difference between total forcing and GHG forcing, but should be approximately the same).

A follow - up question related to where we might lose contact between historical and future is the disproportionate role of aerosols on the asymmetries in climate forcing.

They, too, assume an equivalence in radiative forcing between GHG and aerosol, What they do is add different estimates of the aerosol radiative forcing to the GHG forcing, while keeping the temperature response fixed at the observed recent warming.

The expected global average direct + indirect forcings for aerosols vary between -1.0 (Japan) and -1.4 W / m2 (Hansen, IPCC) for the past centuries and -0.9 to -1.3 W / m2 for future (2050, 2100) emissions (Canada).

Aerosols exert a forcing on the hydrological cycle by modifying cloud condensation nuclei, ice nuclei, precipitation efficiency, and the ratio between solar direct and diffuse radiation received.

«The overall slight rise (relative heating) of global total net flux at TOA between the 1980's and 1990's is confirmed in the tropics by the ERBS measurements and exceeds the estimated climate forcing changes (greenhouse gases and aerosols) for this period.

Boucher (1995) showed that, if this difference is to be attributed to anthropogenic aerosols, it implies a differential forcing of about -1 Wm - 2 between the two hemispheres.

However, detection and attribution analyses based on climate simulations that include these forcings, (e.g., Stott et al., 2006b), continue to detect a significant anthropogenic influence in 20th - century temperature observations even though the near - surface patterns of response to black carbon aerosols and sulphate aerosols could be so similar at large spatial scales (although opposite in sign) that detection analyses may be unable to distinguish between them (Jones et al., 2005).

If only GHG forcing is used, without aerosols, the surface temperature in the last decade or so is about 0.3 - 0.4 C higher than observations; adding in aerosols has a cooling effect of about 0.3 - 0.4 C (and so cancelling out a portion of the GHG warming), providing a fairly good match between the climate model simulations and the observations.

Based on the rather vast uncertainties in aerosol forcing, and the substantial discrepancies between model projections of ocean heat uptake and measured heat uptake (ARGO), it strikes me as bizarre that the IPCC insists on excluding the possibility of quite low sensitivity, when there is a wealth of evidence for fairly low sensitivity.

More than a decade ago I published a peer - reviewed paper that showed the UK's Hadley Centre general circulation model (GCM) could not model climate and only obtained agreement between past average global temperature and the model's indications of average global temperature by forcing the agreement with an input of assumed anthropogenic aerosol cooling.

Research published in 2008 by Arizona State University professor Peter Crozier suggests that this nanoscale atmospheric aerosol species is abundant in the atmosphere over East Asian countries and should be explicitly included in models of radiative forcing (the gap between energy radiation reaching the Earth and that leaving through the upper atmosphere).

Answer the question: If you had to use words to describe the relationship between the reported ECS and aerosol forcing what you see would you call it

Looking solely at direct relationships between forcing factors (TSI, aerosols, etc.) and temperature ignores any time lags in the climate system.

This point was also made by Schmidt et al. (2014), which additionally showed that incorporating the most recent estimates of aerosol, solar, and greenhouse gas forcings, as well as the El Niño Southern Oscillation (ENSO) and temperature measurement biases, the discrepancy between average GCM global surface warming projections and observations is significantly reduced.

Has any similar analysis been done on the CMIP5 ensemble, to show the correlation (or lack thereof) between estimated ECS, and historical values for total anthropogenic forcing and aerosol forcing?

However the CMIP5 models show no particular correlation between ECS and total forcing or effective aerosol forcing (which includes the indirect effect).

Figure 2 shows the correlation between total anthropogenic forcing and forcing due to tropospheric aerosols.

So, to answer my own question, the inverse correlation between CS and aerosol forcing isn't as strong, but it's likely not zero.

There is a strong positive correlation between these two quantities with a near 3-fold range in the magnitude of aerosol forcing applied over the 20th century.»

There is medium confidence that this difference between models and observations is to a substantial degree caused by unpredictable climate variability, with possible contributions from inadequacies in the solar, volcanic, and aerosol forcings used by the models and, in some models, from too strong a response to increasing greenhouse - gas forcing.