Sentences with phrase «atmospheric changes during»

req'd), looked at temperature and atmospheric changes during the past 400,000 years.

req'd), looked at temperature and atmospheric changes during the Middle Ages.

Not exact matches

«Using a numerical climate model we found that sulfate reductions over Europe between 1980 and 2005 could explain a significant fraction of the amplified warming in the Arctic region during that period due to changes in long - range transport, atmospheric winds and ocean currents.

Using sophisticated atmospheric and climate models, the researchers estimated the levels of PM2.5 directly attributable to wildfires during a recent six - year period, 2004 to 2009, as well as under projected future climate change conditions (2046 - 2051).

During the PETM, atmospheric carbon dioxide more than doubled and global temperatures rose by 5 degrees Celsius, an increase that is comparable with the change that may occur by later next century on modern Earth.

Storms also a question mark The attribution studies also looked into storms and rainfall extremes, but the complexity of atmospheric processes during such events made it difficult for scientists to decipher the role of climate change.

Observations of atmospheric carbon dioxide made by aircraft at altitudes between 3 and 6 kilometers (10,000 - 20,000 feet) show that seasonal carbon dioxide variations have substantially changed during the last 50 years.

Smit, a professor in UBC's department of earth, ocean & atmospheric sciences, and colleague, professor Klaus Mezger of the University of Bern, were aware that the composition of continents also changed during this period.

The Gulf of Thailand changes from an atmospheric CO2 sink during the boreal winter to a CO2 source in summer due to higher water temperatures, while other sub-regions as well as the entire averaged Sunda Shelf act as a continuous source of CO2 for the atmosphere.

This method tries to maximize using pure observations to find the temperature change and the forcing (you might need a model to constrain some of the forcings, but there's a lot of uncertainty about how the surface and atmospheric albedo changed during glacial times... a lot of studies only look at dust and not other aerosols, there is a lot of uncertainty about vegetation change, etc).

Both communities tend to take the change for granted, and to neglect any purely statistical or chaotic effects which could lead to excursions of the Earth's surface temperature during periods of a couple of decades, without requiring a secular change either in the solar constant or in atmospheric transparency.

Acidity decline in Antarctic ice cores during the Little Ice Age linked to changes in atmospheric nitrate and sea salt concentrations.

The lag between decreases in sea ice extent during late summer and changes in the mid-latitude atmospheric circulation during other seasons (when the recent loss of sea ice is much smaller) needs to be reconciled with theory.

Because melting is so much more energetically efficient than sublimation, the main way that moderate changes in atmospheric conditions — including air temperature — affect ablation is through changing the number of hours during which melting occurs, and the amount of energy available for melting.

Oeschger and his colleagues in Bern were the first to measure the glacial - interglacial change of atmospheric CO2 in ice cores, showing that atmospheric concentrations of CO2 during the glacial period was 50 % lower than the pre-industrial concentration, a result predicted by Arrhenius nearly a century earlier.

The lag between decreases in sea ice extent during late summer and changes in the mid-latitude atmospheric circulation during other seasons (like autumn and winter, when the recent loss of sea ice is much smaller) have been demonstrated empirically, but have not been captured by existing dynamical models.

A. Unless there are significant changes in atmospheric circulation and cooling during the winter, it is unlikely that the Arctic ice thickness would recover.

we use global - scale atmospheric CO2 measurements, CO2 emission inventories and their full range of uncertainties to calculate changes in global CO2 sources and sinks during the past 50 years.

In the real world the most obvious and most common reason for a change in atmospheric density occurs naturally when the oceans are in warming mode and solar irradiation is high as during the period 1975 to 1998.

It is virtually certain that millennial - scale changes in atmospheric CO2 associated with individual antarctic warm events were less than 25 ppm during the last glacial period.

That may mean that natural factors, such as changes in solar radiation, played a larger role in atmospheric carbon dioxide than reforestation during this time, Pongratz said.

«What's really been exciting to me about this last 10 - year period is that it has made people think about decadal variability much more carefully than they probably have before,» said Susan Solomon, an atmospheric chemist and former lead author of the United Nations» climate change report, during a recent visit to MIT.

Volcanic activity proceeds over the decades at a level of only about 1 percent of industrial CO2 emissions, and even major eruptions observed during the past century have changed atmospheric CO2 trends only minimally and transiently.

Köhler, P. & Fischer, H. Simulating low frequency changes in atmospheric CO2 during the last 740 000 years.

there has been no statistically discernible rise in global temperature for the most recent 15 years despite atmospheric CO2 concentration rising by ~ 4 % during that time so the rise in the CO2 is observed to not be overwhelming other causes of the temperature change, 2.

Together with the long - term decrease of 15 p.p.m.v. during the past four glacial cycles, we suggest significant slow fluctuations in the atmospheric CO2 concentration on timescales of several 105 years, probably influenced by changes in the weathering14 or by major reorganizations in the carbon reservoir of the global ocean15.

In some locations, changes in ocean temperatures and atmospheric patterns brought about by El Niño lead to drier conditions, which increases the damage during «fire season».

Large positive SST anomalies in the central and eastern Pacific during El Niño tend to focus convective activity (thunderstorms, tropical storms, etc.) into those regions while suppressing activity elsewhere via both changes in atmospheric stability and wind shear.

It has been postulated that teleconnections, oceanic and atmospheric processes, on different timescales, connect both hemispheres during abrupt climate change.

I'm sure you are right that it will have been rare for a perfect atmospheric equilibrium to have existed for any extended period, but reasonably close approximations are not improbable during times when climate was not measurably changing (again with reference only to global changes).

1) During the time period when CO2 measurements have been made in Mauna Loa the most visible changes in the increasing rate of the atmospheric CO2 content are caused by the seasonal variability in the exchange rate of CO2 between biosphere and atmosphere; e.g. Bob Tisdale http://i37.tinypic.com/al6ips.jpg.

Actually, changing sea surface temperature has dominated the changes of atmospheric CO2 content during all the 20th century.

If there was such evidence then I would see a scientific basis for the conclusion something has really changed in the global atmospheric temperature record during the new century compared to the decades before.

So warmer - than - normal surface waters in the South Atlantic created by the changes in atmospheric circulation during an El Niño should be transported northward into the North Atlantic (and vice versa for a La Niña).

One explanation for the seasonal offset is that the large summertime snow / ice change alters ground temperatures, and these ground temperature changes are felt more at ground - level during winter when the surface atmospheric layer is most stable.

Here we find a long list of climate components that «are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century.»

The atmospheric heating and cooling rates are then passed back to the atmosphere structure module that calculates how much the surface and atmospheric temperatures would change during the 30 - minute times step given the radiative heating and cooling rates.

A more definitive reconciliation of modeled and observed temperature changes awaits the extension and improvement of the observations and the algorithms used in processing them, better specification of the natural and human - induced climate forcings during this period, and improvement of the models used to simulate the atmospheric response to these forcings.break

Singh and her Lamont colleagues research climate change impacts on weather patterns by analyzing weather trends in daily temperatures, precipitation, and atmospheric patterns that have occurred during the past 40 years, in the post-satellite era.

You do not disagree with my point but now throw in changes in atmospheric CO2 as evidence that the current rate of warming must have been greater than that occurring during some 50 + year period of the MWP, when there was no such increase in human GHGs..

Identifies changes in occurrence of atmospheric circulation patterns by measuring the similarity of the cool - season atmospheric configuration that occurred in each year of the 1949 — 2015 period with the configuration that occurred during each of the five driest, wettest, warmest, and coolest years

There are no measurements of DIC which could reliably indicate its global change during the recent period of rising atmospheric CO2 concentration.

During El Niño, the unusually warm surface temperatures in the eastern Pacific lead to changes in atmospheric circulation, causing unusually wetter winters in the southwestern United States and thus wider tree rings (representing more growth of the tree).

«If we cause large sea - level rise, that dominates future risks, but if we could prevent sea - level rise and just have the storm surge to worry about, our projections show little change in coastal risk from today during most years,» said Michael Mann, distinguished professor of meteorology and atmospheric science and director of Penn State's Earth System Science Centre, and one of the authors.

Synchronous change of atmospheric CO2 and Antarctic temperature during the last deglacial warming.

These rapid changes in atmospheric CO2 and CH4 concentrations are also recorded during the Heinrich Stadials of MIS 3, demonstrating an important mechanism that operates on centennial time scales during the glacial and deglaciation, which may point to important thresholds in the global carbon cycle.

One implication is that if humans burn most of the fossil fuels, thus injecting into the atmosphere an amount of CO2 at least comparable to that injected during the PETM, the CO2 would stay in the surface carbon reservoirs (atmosphere, ocean, soil, biosphere) for tens of thousands of years, long enough for the atmosphere, ocean and ice sheets to fully respond to the changed atmospheric composition.

They found that changes in atmospheric ionization during the 11 - year solar cycle, and the resulting variations in aerosol formation, produced a globally asymmetric radiative forcing with a net cloud albedo effect of − 0.05 W m − 2.

For example, what about the significant warmings during historical periods (e.g., the MWP) that do not seem correlated with large changes in atmospheric CO2?

Total change in atmospheric CO2 over a period seem to correlate with the average global temperature level during this period.