Sentences with phrase «year variability about»

Not exact matches

Though there's a great deal of variability across bear markets, they tend to last somewhat longer than a year, and take the market down by about 32 % on average.

Schultz, a professor of synoptic meteorology, and co-author Dr Vladimir Janković, a science historian specialising in weather and climate, say the short - term, large variability from year to year in high - impact weather makes it difficult, if not impossible, to draw conclusions about the correlation to longer - term climate change.

Several studies have shown the drug helps about half of the people who take it lose more than 5 percent of their body mass within a year, but there's a great deal of variability in individual results, and the mechanism underlying its effect was previously unknown.

I plotted out the variability in million - year intervals and found that about 6 million years ago, that variability went off the charts and kept increasing.

It ended up changing the limit Jan Veizer and I could impose (from Tx2 < 1 °C, to about 1 - 1.5 °C), but it did not invalidate the apparent role that cosmic rays appear to play on the multi-million year climate variability).

Variability in the tracks on a year by year basis, for instance, as diagnosed by the models NAO index resembles that observed, explaining about the same amount of variability aVariability in the tracks on a year by year basis, for instance, as diagnosed by the models NAO index resembles that observed, explaining about the same amount of variability avariability as observed.

Thus, given natural variability, 20 years is only enough time to start tell apart (in a statistical significant fashion) trends that are at least disparate by about 0.15 ºC / decade.

For instance, an influential analysis by Hawking & Sutton (2009)(link to figures) has suggested that internal climate variability account for only about 20 % of the variance over the British isles on a 50 - year time scale.

During the Holocene optimum at a time when Wolcott shows less than 0.2 C of variability, Rosenthal shows an upset in NH IWT that has the temperature rising 2C in about 500 years.

Mike's work, like that of previous award winners, is diverse, and includes pioneering and highly cited work in time series analysis (an elegant use of Thomson's multitaper spectral analysis approach to detect spatiotemporal oscillations in the climate record and methods for smoothing temporal data), decadal climate variability (the term «Atlantic Multidecadal Oscillation» or «AMO» was coined by Mike in an interview with Science's Richard Kerr about a paper he had published with Tom Delworth of GFDL showing evidence in both climate model simulations and observational data for a 50 - 70 year oscillation in the climate system; significantly Mike also published work with Kerry Emanuel in 2006 showing that the AMO concept has been overstated as regards its role in 20th century tropical Atlantic SST changes, a finding recently reaffirmed by a study published in Nature), in showing how changes in radiative forcing from volcanoes can affect ENSO, in examining the role of solar variations in explaining the pattern of the Medieval Climate Anomaly and Little Ice Age, the relationship between the climate changes of past centuries and phenomena such as Atlantic tropical cyclones and global sea level, and even a bit of work in atmospheric chemistry (an analysis of beryllium - 7 measurements).

In so far as M&M are trying to distort the climate data over the last 1000 years to show that the so - called «Medieval Warm Period» replicates or exceeds the current warming — and so natural variability could possibly account for that warming — I thought it worthwhile to put out some information about Medieval climate.

However, in the paper the authors actually stated that «our conclusion about the dominance of the CRF over climate variability is valid only on multimillion - year time scales».

As to the bottom line, we are talking about changes to a fundamental part of the ocean carbon cycle, far outside the range of natural variability, that are irreversible and will last for thousands of years.

As presented below, the temperature record of each of these groups (available at the URLs given at the bottom of this message) shows the same features: (i) a warming of about 0.9 °C (1.6 °F) over the past 150 years and (ii) natural variability with both short and long periods.

If you are talking about climate variability on the scale of 100,000 years then it's clearly a feedback.

The models and observations both also indicate that the amplitude of interannual variability about these longer - term trends is quite large, making it foolhardy, at best, to try to estimate the slope of anthropogenic warming from a few years of data (as you seem to advocate).

And, that just coincidently, the rate of the rise has consistently been (when averaged over a few year period to smooth out variability due to seasonal cycles and other factors) equal to about half of the emissions of CO2 that we are putting into the atmosphere?

Based on results from large ensemble simulations with the Community Earth System Model, we show that internal variability alone leads to a prediction uncertainty of about two decades, while scenario uncertainty between the strong (Representative Concentration Pathway (RCP) 8.5) and medium (RCP4.5) forcing scenarios [possible paths for greenhouse gas emissions] adds at least another 5 years.

This period is pointed out by low interannual variability of tree growth and high trees abundance discontinued, however, by several short (50 - 100 years) unfavorable periods, most significant of them dated about 4060 - 3990 BC.

This is the same Ed Cook who admitted in the first dossier that we know «f *** all» about climate variability > 100 years based on dendro.

«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,

The thing is, it's not enough to look at a 10 year period in isolation and I would certainly hesitate to draw conclusions about multidecadal variability based on 10 years of data.

The U.S. military seems interested in climate variations / change on timescales from seasonal to scales out to about 30 years, a period over which natural climate variability could very well swamp anthropogenically forced climate change.

So in the case of climate, we know the variability over the last 10000 years is about 2K (see Muller).

«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.

In most regions, instrumental records of variability typically extend only over about 150 years, so there is limited information to characterise how extreme rare climatic events could be.

Models all produce natural variability, many of which show temperature flatlines over decadal timescales, and given the wide importance of natural variability over < 10 year time scales and uncertain forcings, one can absolutely not claim that this is inconsistent with current thinking about climate.

Data over 140 years is insufficient to make over broad claims about natural variability and it would require a leap of imagination to use this data in and of itself to draw conclusions about cause and effect.

This many - year project has been motivated solely by curiosity about natural variability at this time scale.

It has also been known that a component of the variability seems to have a full period of about 60 years although the evidence has not been strong on any real periodicity or even quasi-periodicity.

In 1990, two years after NASA scientist James E. Hansen issued his now famous warning about climate change during a congressional hearing, Lindzen started taking a publicly contrarian stance when he challenged then - senator Gore by suggesting in the Bulletin of the American Meteorological Society that the case for human - induced global warming was overstated and that natural climate variability could explain things just as easily.

The observed variability around the trend is about + / - 1 ppmv or + / - 2 GtC over the past 50 years, with the 1992 Pinatubo and 1998 El Nino at maximum — and + amplitude.

We were talking about the variability of the CO2 increase over the past 50 years.

Variability is part of the climate system and a 15 - year hiatus, they suggested, was not worth getting excited about.»

Without trying to prejudice this work, but also because of what I almost think I know to be the case, the results of this study will show that we can probably say a fair bit about < 100 year extra-tropical NH temperature variability (at least as far as we believe the proxy estimates), but honestly know f *** - all about what the > 100 year variability was like with any certainty (i.e. we now with certainty that we know f *** - all).

The AMO during the Little Ice Age was characterized by a quasi-periodicity of about 20 years, while the during the Medieval Warm Period the AMO oscillated with a period of about 45 to 65 years... The observed intermittency of these modes over the last 4000 years supports the view that these are internal ocean - atmosphere modes, with little or no external forcing... However, the geographic variability of these periodicities indicated by ice core data is not captured in model simulations.»

And, the overall trend across all the recorded data is the same as its been since the end of the LIA, plus or minus an additional quasi-periodic variability with a cycle time of about 60 years, which also has been in existence since the end of the LIA.

The fact that unforced variability in the climate system can offset anthropogenic forcing changes on a time scale of about 15 years and smaller does not logically imply that unforced variability is also the primary cause of the statistically significant temperature increase since the mid 1970ies.

Now you have talked about 4 years weather data having a meaning (0.25 degree climb in GAT) whereas we all know that natural variability on a seasonal basis at least in Australia can be around 10 degrees C and on a daily basis something around the same as well.

Other years show regional variability, but all have about the same total extent.

Irrespective of what one thinks about aerosol forcing, it would be hard to argue that the rate of net forcing increase and / or over-all radiative imbalance has actually dropped markedly in recent years, so any change in net heat uptake can only be reasonably attributed to a bit of natural variability or observational uncertainty.

The direct climate forcing due to measured solar variability, about 0.2 W / m2, is comparable to the increase in carbon dioxide forcing that occurs in about seven years, using recent CO2 growth rates.

Natural variability in the N.H. during last 130 years accounts for about 0.75 C, which is half of 1.5 C that is attributed to the GHG by the BEST report.

Exactly, but using good numbers not a «hotchpotch assembly» for which it is claimed to be global temperature (there is no such thing, there is global energy content, but that is totally different story) So calculate correlation CET - GT from 1880 using 5 year bin averaging http://www.vukcevic.talktalk.net//CETGNH.htm P.S. your statement on natural variability on decadal scale is grossly misleading, you got about 130 years of good records so you need to look at multi-decadal picture.

I don't consider myself to be an expert by any means but in the few years I have been taking an interest in the subject of climate change I have tried to educate myself as much as possible about the various scientific arguments surrounding the subject, and one thing that has constantly been impressed upon my mind is that when there is a long term trend caused by increasing GHG levels there will periods when it is masked (or accentuated) by short term natural variability.

The SDO mission NASA has just launched will hopefully reveal more, though how much a 5 year mission will tell us about multidecadal variability remains to be seen.

Now forced to explain the warming hiatus, Trenberth has flipped flopped about the PDO's importance writing «One of the things emerging from several lines is that the IPCC has not paid enough attention to natural variability, on several time scales,» «especially El Niños and La Niñas, the Pacific Ocean phenomena that are not yet captured by climate models, and the longer term Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) which have cycle lengths of about 60 years.»

For a long time this has seemed to me to be the most obvious source of global hydrological variability on about a 25 year interval — and these hydrological variabilities are associated with the most significant surface temperature variations in recent times — and seemingly with the MWP and LIA.

They should have, however, emphasized more the fact that they can not tell anything about variability over periods of about 300 years or less.

It takes about 20 years to evaluate because there is so much unforced variability in the system which we can't predict — the chaotic component of the climate system — which is not predictable beyond two weeks, even theoretically.