Sentences with phrase «century scale variability»

These linear discriminants, which consist of an RASST anomaly field and a time series that describes the projection of that anomaly in the annual mean RASST field, maximize the ratio of inter-decadal to inter-annual variability, in keeping with our desire to understand the decadal - to - century scale variability in the global mean surface temperatures (see SI Text and Figs.

Not exact matches

The other problem is that the scale of the difference is masked more readily by variability, events such as Krakatoa, and the needs of statistics to hit significance levels... TBH I haven't done the math, but we shouldn't be surprised if we now achieve in a year, in emissions terms, what would have taken most of the nineteenth century to manage.

The blue colour on the left - hand side shows the natural variability periods, the yellow = early 20th century, red = late 20th century, and the grey and black denote data from SODA and HadlSST (scaled with NCEP / NCAR SAT) respectively.

«It is odd to me to think of century - scale hydroclimate variability in terms of «extremes», a term typically reserved in climate science for timescales of hours to years.»

Furthermore, since the end of the 19th century, we find an increasing variance in multidecadal hydroclimatic winter and spring, and this coincides with an increase in the multidecadal North Atlantic Oscillation (NAO) variability, suggesting a significant influence of large - scale atmospheric circulation patterns.

She goes so far as to say (in her post responding to Gavin's post, but responding to something else) «I do regard the emerging realization of the importance of natural variability to be an existential threat to the mainstream theory of climate variations on decadal to century time scales.»

If the influence of solar variability has been greatly underestimated, and the greater century - scale climate variability shown in some reconstructions is a) correct and b) due to that solar variability, then the climate sensitivity could be the same (or less) then indicated by other reconstructions.

A key result is a reconstruction showing more century - scale variability in mean Northern Hemisphere temperatures than is shown in previous reconstructions.

Much was made of the possibility that this reconstruction might indicate greater sensitivity than other previously published reconstrucitons, because of the greater century - scale variability.

The previous message mentioned CENTURY TIME SCALES, not INTERANNUAL variability.

But there remains far too much natural variability in the frequency and potency of rare and powerful storms — on time scales from decades to centuries — to go beyond pointing to this event being consistent with what's projected on a human - heated planet.

This simply arises from chance, and the fact that there are very few realizations of the century - scale variability present in the two short forcing series.

I did a simple calculation on a time scale of several centuries, and only the Sun has such long range variability.

Long - term natural variability has implications for the modeling of future climate changes, on the scale of decades to centuries.

The suggested synchroneity of tropical and North Atlantic centennial to millennial variability (de Menocal et al., 2000; Mayewski et al., 2004; Y.J. Wang et al., 2005) is not common to the SH (Masson et al., 2000; Holmgren et al., 2003), suggesting that millennial scale variability can not account for the observed 20th - century warming trend.

Forest (2006) states: «It is not possible to estimate the true climate system variability on century time - scales from observations and therefore, climate models are run with fixed boundary conditions for thousands of years to obtain estimates of the climate variability.»

«Our analysis shows warming underway by 1800, large variations up and down throughout the 19th century, and that variability on the 3 - 15 year scale has been dramatically decreasing over the past two centuries.»

The study by Macias & Johnson (2008) provides not only evidence for the link between decadal - scale changes in the teleconnection patterns (e.g. the Pacific Decadal Oscillation (PDO) index) and the increased fire frequency in the late twentieth century but also an explanation of why the pattern of fire variability and fire - climate relationships changes at different time scales from centennial / decadal to interannual.....

It very quickly became evident the the Pacific state shifted at these 20 to 30 year intervals in ways that summed to variability at millennial scales — and that the millennial peak in the 20th century was likely to pass this century.

Therefore, the processes of accumulation and ablation are the physical link between glaciers and climate, which explains why these ice bodies are such valuable tracers of climate variability on the scale of decades and centuries.

The IPCC treats natural internal variability as «noise»; we argue that it is the fundamental climate signal on decadal to century time scales, with external forcing projecting onto these modes.

natural internal variability can be pretty large on decadal to century time scales, and minimization of this variability by the hockey team has been very damaging to the science and the identification and intepretation of natural variability.

Noteworthy in the reconstructions are the post-1976 warm / wet period, unprecedented in the 1,425 - year record both in amplitude and duration, anomalous and prolonged late 20th century warmth, that while never exceeded, was nearly equaled in magnitude for brief intervals in the past, and substantial decadal - scale variability within the Medieval Warm Period and Little Ice Age intervals.

It is assumed above that natural variability in the future will resemble that of the past (on a century scale).

rw (05:22:03): «The motions of the massive oceans where heat is moved between deep layers and the surface provides variability on time scales from years to centuries.

This suggests that natural variability overwhelms the forced response in the observations» — Stenni et al., 2017 http://www.clim-past-discuss.net/cp-2017-40/cp-2017-40.pdf «No continent - scale warming of Antarctic temperature is evident in the last century.

''... worked with two sediment cores they extracted from the seabed of the eastern Norwegian Sea, developing a 1000 - year proxy temperature record «based on measurements of δ18O in Neogloboquadrina pachyderma, a planktonic foraminifer that calcifies at relatively shallow depths within the Atlantic waters of the eastern Norwegian Sea during late summer,» which they compared with the temporal histories of various proxies of concomitant solar activity... This work revealed, as the seven scientists describe it, that «the lowest isotope values (highest temperatures) of the last millennium are seen ~ 1100 - 1300 A.D., during the Medieval Climate Anomaly, and again after ~ 1950 A.D.» In between these two warm intervals, of course, were the colder temperatures of the Little Ice Age, when oscillatory thermal minima occurred at the times of the Dalton, Maunder, Sporer and Wolf solar minima, such that the δ18O proxy record of near - surface water temperature was found to be «robustly and near - synchronously correlated with various proxies of solar variability spanning the last millennium,» with decade - to century - scale temperature variability of 1 to 2 °C magnitude.»

«We use geochemical data from a sediment core in the shallow - silled and intermittently dysoxic Kau Bay in Halmahera (Indonesia, lat 1 ° N, long 127.5 ° E) to reconstruct century - scale climate variability within the Western Pacific Warm Pool over the past ~ 3500 yr.

Downcore variations in bulk sedimentary δ15N appear to reflect century - scale variability in basin ventilation, attributed to changes in oceanographic conditions related to century - scale fluctuations in El Niño Southern Oscillation (ENSO).

Comparison with the literature shows that the CSSR draft misleads by omission in not mentioning both the strong decadal ‐ scale variability of GMSL rates during the 20th century and the fact that the most recent values of the rate are statistically indistinguishable from those during the first half of the 20th century.

The climate exhibits significant long term variability on the scale of centuries to millennia.

The relationships between the NAO and deep water production are discussed by R. Dickson, «Observations of DecCen climate variability in convection and water mass formation in the northern hemisphere,» in the CLIVAR Villefranche workshop summary at http://www.dkrz.de/clivar/villesum.html. More generally, see the Climate Research Committee, National Research Council, Natural Climate Variability on Decade - to - Century Time Scales (National Academy Pvariability in convection and water mass formation in the northern hemisphere,» in the CLIVAR Villefranche workshop summary at http://www.dkrz.de/clivar/villesum.html. More generally, see the Climate Research Committee, National Research Council, Natural Climate Variability on Decade - to - Century Time Scales (National Academy PVariability on Decade - to - Century Time Scales (National Academy Press 1995).

The absolute most that can be said is that it's possible that the role of natural variability amplifying warming post-1975 has been * slightly * under - stated, but on a century scale this means nothing.

On short time scales (decade to centuries), there is no satisfactory way of sorting out forced climate variability from natural internal climate variability unless you have a really good climate model that can adequately handle the natural internal variability on the range of time scales from years to millennia.

The petition reads in part: «Studies of a variety of natural processes, including ocean cycles and solar variability, indicate that they can account for variations in the Earth's climate on the time scale of decades and centuries.

Robert R. Dickson, «The local, regional, and global significance of exchanges through the Denmark Strait and Irminger Sea,» in Natural Climate Variability of Decade - to - Century Time Scales (National Academy Press 1995), pp. 305 - 317.

The motions of the massive oceans where heat is moved between deep layers and the surface provides variability on time scales from years to centuries.

Given that the past 30 — 50 years is a relatively short period for evaluating long - term trends, the SST trends themselves could be viewed as a manifestation of large - scale modes of multidecadal Pacific variability (e.g. Zhang et al. 1997; Deser et al. 2004) or as part of the century scale positive SST trends associated with climate change (e.g. Deser et al. 2010); it is likely that both multidecadal climate variability and climate change have contributed to the SST trend pattern evident in Fig. 9 and used to force the model.

I co-edited and contributed to the 2003 American Geophysical Union Monograph: The North Atlantic Oscillation: significance and environmental impact and was one of the authors of the 1995 National Academies report on Climate Variability on Decade - to - Century Time Scales.

See for example these National Research Council reports: «Natural Climate Variability on Decade - to - Century Timescales (NAP, 1995)» and «Decade - to - Century - Scale Climate Variability and Change (NAP, 1998).

«Pooled all of the Holocene global temperature anomalies into a single histogram, showing the distribution of global temperature anomalies during the Holocene, including the decadal - to century scale high - frequency variability...»

You can do as Lovejoy (2014, Clim Dyn) did, which is to derive a natural variability of global surface temperature from solar and volcanic forcing which is 0.2 C for decades to century time scales.

The possibility that natural variability explains the century - scale observed rise in atmospheric CO2 can easily be dismissed based on simple accounting (anthropogenic emissions are larger than the rise itself, and thus account for over 100 % of the observed rise).

The «changing system» could be internal variability of the system, which would have a zero - sum game over the longer - term (century scale), or some external forcing on the system, which could bring about very long - term changes to the climate lasting thousands or tens of thousands of years.

A long time - scale is needed because significant multidecadal variability appears in numerous tide gauge records during the 20th century.

«Differing amplitudes resulting from borehole and tree ring climate proxies suggest that longer time scale (multidecadal and century) variability is more faithfully captured by borehole results, while the same information can be irretrievably lost in tree ring records...»

I could see the climat itself having some sort of variability on that timescale, but then the century and millenial scale story doesn't seem to make sense.

Different approaches have been used to compute the mean rate of 20th century global mean sea level (GMSL) rise from the available tide gauge data: computing average rates from only very long, nearly continuous records; using more numerous but shorter records and filters to separate nonlinear trends from decadal - scale quasi-periodic variability; neural network methods; computing regional sea level for specific basins then averaging; or projecting tide gauge records onto empirical orthogonal functions (EOFs) computed from modern altimetry or EOFs from ocean models.

The mean state of ENSO, its global patterns of influence, amplitude of interannual variability, and frequency of extreme events show considerable multidecadal and century - scale variability over the past several centuries.»

Figure 2: Eight records of local temperature variability on multi-centennial scales throughout the course of the Holocene, and an average of these (thick dark line) over the past 12,000 years, plotted with respect to the mid 20th century average temperature.