Sentences with phrase «aerosol models over»

FMI has been involved in research project, which evaluated the simulations of long - range transport of BB aerosol by the Goddard Earth Observing System (GEOS - 5) and four other global aerosol models over the complete South African - Atlantic region using Cloud - Aerosol Lidar with Orthogonal Polarization (CALIOP) observations to find any distinguishing or common model biases.

Not exact matches

A few of the main points of the third assessment report issued in 2001 include: An increasing body of observations gives a collective picture of a warming world and other changes in the climate system; emissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to affect the climate; confidence in the ability of models to project future climate has increased; and there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.

Using climate models and data collected about aerosols and meteorology over the past 30 years, the researchers found that air pollution over Asia — much of it coming from China — is impacting global air circulations.

Geoengineering activities are mimicked in the models by modifying the volcanic aerosol radiative inputs, applied as variations in stratospheric optical depth over four zonal bands bounded by the equator, 30degreesN and 30degreesS.

Regional aerosol models represent important aerosol properties and processes by integrating a suite of property and process models for a limited geographic area over a limited time span.

The Hadcm3 model has calculated the largest increase in temperature which may be attributed to the reduction of aerosol load (40 %) over the period 1990 - 1999 somewhere in NE Europe, other models do that more in Southern Europe.

For sulphate aerosols, current models probably overestimate their influence, as there is no measurable effect of the large (over 60 %) reduction in SO2 emissions in Europe at the places where the largest influence should be visible, according to the models.

Now, with the Aerosol Modeling Testbed, scientists can systematically and objectively evaluate new aerosol process modules over a wide range of spatial and temporal Aerosol Modeling Testbed, scientists can systematically and objectively evaluate new aerosol process modules over a wide range of spatial and temporal aerosol process modules over a wide range of spatial and temporal scales.

Note too that the models do include representations of aerosol changes over this period — though imperfectly.

They only underestimated the observed trend by about 30 %, similar or better in magnitude than the CMIP5 models over the same period (although these tend to overestimate the trend, still mainly due to problems related to aerosols).

If the models are too sensitive to CO2 or over or under - estimating aerosol effects, and failing to include natural variations like the ENSO and PDO and AMO wouldn't this fit «reality» more closely?

We can derive the underlying trend related to external forcings from the GCMs — for each model, the underlying trend can be derived from the ensemble mean (averaging over the different phases of ENSO in each simulation), and looking at the spread in the ensemble mean trend across models gives information about the uncertainties in the model response (the «structural» uncertainty) and also about the forcing uncertainty — since models will (in practice) have slightly different realisations of the (uncertain) net forcing (principally related to aerosols).

Since the true impacts of longer term natural variability are not known and the one confidence estimates of aerosol and cloud forcings used to tune the models to that «range of comfort» are quite a bit more uncertain that previously considered, that it might just be time for a do over.

So the model run in 2001 could not possibly include the very low solar minimum of 2008 - 2009, or the increase in human aerosols from Asia, natural aerosols, or the trend of more La Nina's over the past decade, etc..

Our model's sensitivity has varied over the years as a function of a number of issues — and we have not adjusted our aerosol forcings to match.

Here we apply such a method using near surface air temperature observations over the 1851 — 2010 period, historical simulations of the response to changing greenhouse gases, aerosols and natural forcings, and simulations of future climate change under the Representative Concentration Pathways from the second generation Canadian Earth System Model (CanESM2).

Christy is correct to note that the model average warming trend (0.23 °C / decade for 1978 - 2011) is a bit higher than observations (0.17 °C / decade over the same timeframe), but that is because over the past decade virtually every natural influence on global temperatures has acted in the cooling direction (i.e. an extended solar minimum, rising aerosols emissions, and increased heat storage in the deep oceans).

The input of assumed anthropogenic aerosol cooling is needed because the model «ran hot»; i.e. it showed an amount and a rate of global warming which was greater than was observed over the twentieth century.

None of the models — not one of them — could match the change in mean global temperature over the past century if it did not utilise a unique value of assumed cooling from aerosols.

The model that I have described, warming due to the removal of anthropogenic SO2 aerosols, largely due to clean air efforts, perfectly matches the behavior of climate change over the past 40 years.

If the aerosol hypothesis were correct then the global distribution of warming and cooling over the twentieth century would be matched by the model which was adjusted with the 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).

However, given that the CAGW position doesn't rest on specific numbers, but is instead an unorganized collection of anecdotal evidence, coupled with heavily - tweaked computer models, unfounded assumptions about positive feedbacks, and a healthy imagination about possible future disasters, a lower warming number for the 20th century will simply be brushed over with claims about aerosols being stronger than previously thought, more warming still waiting in the «pipeline» or similar ad hoc «explanations» that keep the overall story alive.

Gregory and Oerlemans (1998) applied local seasonal temperature changes over 1860 to 1990 calculated by the HadCM2 AOGCM forced by changing greenhouse gases and aerosols (HadCM2 GS in Table 9.1) to the glacier model of Zuo and Oerlemans.

2) CAGW movement type models never reconstruct any lengthy past history accurately without creative and unique adjustment of aerosol values used as a fudge factor; that is why models of widely varying sensitivities supposedly all accurately reconstruct the past (different made - up assumed historical values used for each) but fail in future prediction, like they didn't predict how global average temperatures have been flat to declining over the past 15 years.

Our understanding 48 of the «ion - aerosol clear air» mechanism as a whole relies on a few model investigations that simulate GCR 49 changes over a solar cycle (Kazil et al., 2012; Pierce and Adams, 2009a; Snow - Kropla et al., 2011) or during 50 strong Forbush decreases (Bondo et al., 2010; Snow - Kropla et al., 2011).

- that new estimates of aerosol cooling are low - that new estimates of Ocean heat uptake are low - that therefore observational estimates of climate sensitivity may prove low - that observational estimates are now good enough that they should be preferred over models - that warming below 2C is net beneficial

All I know is that Schmidt, Santer, et al seem to agree that the climate models over predicted the warming because the models under - estimated negative forcing due to stratospheric aerosols.

«In our mor recent global model simulations the ocean heat - uptake is slower than previously estimated, the ocean uptake of carbon is weaker, feedbacks from the land system as temperature rises are stronger, cumulative emissions of greenhouse gases over the century are higher, and offsetting cooling from aerosol emissions is lower.

Even if we could assign a certain fraction of warming over the past century or so to natural variation, we still would face very large uncertainty in aerosol influences... and modelers would continue to use those vastly uncertain aerosol influences as as a «free» variable to «tune» the models.

In the article «Global atmospheric particle formation from CERN CLOUD measurements,» sciencemag.org, 49 authors concluded «Atmospheric aerosol nucleation has been studied for over 20 years, but the difficulty of performing laboratory nucleation - rate measurements close to atmospheric conditions means that global model simulations have not been directly based on experimental data.....

A modeling study of the direct effect of aerosol over the Tropical Indian Ocean.

Myhre, G., N. Bellouin, T.F. Berglen, T.K. Berntsen, O. Boucher, A. Grini, I.S.A. Isaksen, M. Johnsrud, M.I. Mishchenko, F. Stordal, and D. Tanre, 2007: Comparison of the radiative properties and direct radiative effect of aerosols from a global aerosol model and remote sensing data over ocean.

Their model found that the unprecedented increase in monsoon activity over the past 30 years is «due possibly in part to» the rise of CO2 in the atmosphere, but they said the result could be an overestimate because the authors didn't consider the impacts of aerosols, which cool the atmosphere.

Two other important records from satellite instruments — one from MODIS and the other from MISR — don't agree well over land, so scientists hope that data from other other sensors like SeaWiFS might help resolve some of the discrepancies and reduce the overall uncertainty about aerosols in climate models.

What the paper is discussing, and what was glossed over in the release, is that it is the next generation of models, often called «Earth System Models» (ESMs), that are starting to include atmospheric chemistry, aerosols, ozone and themodels, often called «Earth System Models» (ESMs), that are starting to include atmospheric chemistry, aerosols, ozone and theModels» (ESMs), that are starting to include atmospheric chemistry, aerosols, ozone and the like.

There is also a fairly large increase in modelled sulfate load over the Tropical North Atlantic from about 1960, which is presumably the main cause of modelled present day strong aerosol forcing off the West African coast, as depicted in Booth et al. figure 4b.