Sentences with phrase «observed multidecadal»

Can the Atlantic Ocean drive the observed multidecadal variability in Northern Hemisphere mean temperature?

Predictions at longer timescales, such as 10 or 20 yr are also found to be less skillful, given the observed multidecadal variability.

Zhang, R., T. L. Delworth, and I. M. Held, 2007: Can the Atlantic Ocean drive the observed multidecadal variability in Northern Hemisphere mean temperature?

Not exact matches

Delworth, T.L., and M.E. Mann, 2000: Observed and simulated multidecadal variability in the Northern Hemisphere.

«Multidecadal variability of Atlantic tropical cyclone activity is observed to relate to the Atlantic Multidecadal Oscillation (AMO)-- a mode manifesting primarily in sea surface temperature (SST) in the high latitudes of the North Atlantic.

Since the CMIP5 models used by the IPCC on average adequately reproduce observed global warming in the last two and a half decades of the 20th century without any contribution from multidecadal ocean variability, it follows that those models (whose mean TCR is slightly over 1.8 °C) must be substantially too sensitive.

Delworth, T.L., Mann, M.E., Observed and Simulated Multidecadal Variability in the Northern Hemisphere, Climate Dynamics, 16, 661 - 676, 2000.

It presents a significant reinterpretation of the region's recent climate change origins, showing that atmospheric conditions have changed substantially over the last century, that these changes are not likely related to historical anthropogenic and natural radiative forcing, and that dynamical mechanisms of interannual and multidecadal temperature variability can also apply to observed century - long trends.

Ruprich - Robert, Y., F. Castruccio, R. Msadek, S. G. Yeager, T. Delworth, and G. Danabasoglu, 2016: Assessing the climate impacts of the observed Atlantic multidecadal variability using the GFDL CM2.1 and NCAR CESM1 global coupled models.

Assessing the Climate Impacts of the Observed Atlantic Multidecadal Variability Using the GFDL CM2.1 and NCAR CESM1 Global Coupled Models (Journal of Climate)

Researchers observed a natural, regular, multidecadal oscillation between periods of Southern Ocean open - sea convection, which can act a release valve for the ocean's heat, and non-convective periods.

The hypothesis then is that multidecadal climate has only two significant components: the sawtooth, whatever its origins, and warming that can be accounted for 99.98 % by the AHH law as measured by the R2 of its fit to observed global warming (and could be brought even closer to 1 with a good story for MRES).

I should add that anyone who can separate multidecadal climate defined as F3 (HadCRUT3) into the sum of an oscillating component and a concave - downwards trend (the opposite of what I called Observed Global Warming which is concave - upwards) will have the immediate attention of a lot of people.

They do a poor job at simulating the observed modes of natural internal climate variability (e.g. the multidecadal ocean oscillations).

Characterizing and understanding the multidecadal variations of the continental hydrological cycle is a challenging issue given the limitation of observed data sets.

The variations are strongly correlated with the similar decadal fluctuations observed in the Atlantic Multidecadal Oscillation index, and less so with the El Nino Southern Oscillation index.

Zhang, R., T. L. Delworth, R. Sutton, D. L. R. Hodson, K. W. Dixon, I. M. Held, Y. Kushnir, J. Marshall, Y. Ming, R. Msadek, J. Robson, A. J. Rosati, M. F. Ting, and G. A. Vecchi, 2013: Have aerosols caused the observed Atlantic multidecadal variability?

The BEST team found that greenhouse gases and volcanic eruptions could account for most of the observed temperature change, and suggest that the remainder of the variability is fairly consistent with the Atlantic Multidecadal Oscillation (AMO), an ocean cycle, and very little contribution from changes in solar activity (Figure 2).

The above finding reinforces the conclusion of Scafetta (2010b) that the IPCC (2007) GCMs do not reproduce the observed major decadal and multidecadal dynamical patterns observed in the global surface temperature record.

During this period, the rate of this rise has varied on multidecadal time scales making identifying exact reasons behind upswings, such has been observed over the past few decades, difficult.

The decadal variations of the AMOC obtained in that way are shown to precede the observed decadal variations in basin - wide North Atlantic sea surface temperature (SST), known as the Atlantic Multidecadal Oscillation (AMO) which strongly impacts societally important quantities such as Atlantic hurricane activity and Sahel rainfall.

The terrestrial surface is not of uniform heat capacity, so spatial aggregation criteria alone can be responsible for observed amplitudes of multidecadal variation.

Paul Vaughan says: July 26, 2011 at 7:06 am so spatial aggregation criteria alone can be responsible for observed amplitudes of multidecadal variation.

You write, in reference to it: «his choice of ocean heat uptake is based on taking a short term trend over a period in which the observed warming is markedly lower than the longer - term multidecadal value.»

The conclusion is evident, simple and straightforward: all GCMs adopted by the IPCC fail in correctly reproducing the decadal and multidecadal dynamical modulation observed in the global surface temperature record, thus they do not reproduce the observed dynamics of the climate.

Similar decadal and multidecadal cycles have being observed in numerous climatic proxy models for centuries and millennia, as documented in the references of my papers, although the proxy models need to be studied with great care because of the large divergence from the temperature they may present.

1) The IPCC (CMIP3) climate models fail in reproducing observed decadal and multidecadal limate cycles.

Quantitatively, the recurrent multidecadal internal variability, often underestimated in attribution studies, accounts for 40 % of the observed recent 50 - y warming trend.

Superimposed on the secular trend is a natural multidecadal oscillation of an average period of 70 y with significant amplitude of 0.3 — 0.4 °C peak to peak, which can explain many historical episodes of warming and cooling and accounts for 40 % of the observed warming since the mid-20th century and for 50 % of the previously attributed anthropogenic warming trend (55).

The models heavily relied upon by the Intergovernmental Panel on Climate Change (IPCC) had not projected this multidecadal stasis in «global warming»; nor (until trained ex post facto) the fall in TS from 1940 - 1975; nor 50 years» cooling in Antarctica (Doran et al., 2002) and the Arctic (Soon, 2005); nor the absence of ocean warming since 2003 (Lyman et al., 2006; Gouretski & Koltermann, 2007); nor the onset, duration, or intensity of the Madden - Julian intraseasonal oscillation, the Quasi-Biennial Oscillation in the tropical stratosphere, El Nino / La Nina oscillations, the Atlantic Multidecadal Oscillation, or the Pacific Decadal Oscillation that has recently transited from its warming to its cooling phase (oceanic oscillations which, on their own, may account for all of the observed warmings and coolings over the past half - century: Tsoniset al., 2007); nor the magnitude nor duration of multi-century events such as the Mediaeval Warm Period or the Little Ice Age; nor the cessation since 2000 of the previously - observed growth in atmospheric methane concentration (IPCC, 2007); nor the active 2004 hurricane season; nor the inactive subsequent seasons; nor the UK flooding of 2007 (the Met Office had forecast a summer of prolonged droughts only six weeks previously); nor the solar Grand Maximum of the past 70 years, during which the Sun was more active, for longer, than at almost any similar period in the past 11,400 years (Hathaway, 2004; Solankiet al., 2005); nor the consequent surface «global warming» on Mars, Jupiter, Neptune's largest moon, and even distant Pluto; nor the eerily - continuing 2006 solar minimum; nor the consequent, precipitate decline of ~ 0.8 °C in TS from January 2007 to May 2008 that has canceled out almost all of the observed warming of the 2multidecadal stasis in «global warming»; nor (until trained ex post facto) the fall in TS from 1940 - 1975; nor 50 years» cooling in Antarctica (Doran et al., 2002) and the Arctic (Soon, 2005); nor the absence of ocean warming since 2003 (Lyman et al., 2006; Gouretski & Koltermann, 2007); nor the onset, duration, or intensity of the Madden - Julian intraseasonal oscillation, the Quasi-Biennial Oscillation in the tropical stratosphere, El Nino / La Nina oscillations, the Atlantic Multidecadal Oscillation, or the Pacific Decadal Oscillation that has recently transited from its warming to its cooling phase (oceanic oscillations which, on their own, may account for all of the observed warmings and coolings over the past half - century: Tsoniset al., 2007); nor the magnitude nor duration of multi-century events such as the Mediaeval Warm Period or the Little Ice Age; nor the cessation since 2000 of the previously - observed growth in atmospheric methane concentration (IPCC, 2007); nor the active 2004 hurricane season; nor the inactive subsequent seasons; nor the UK flooding of 2007 (the Met Office had forecast a summer of prolonged droughts only six weeks previously); nor the solar Grand Maximum of the past 70 years, during which the Sun was more active, for longer, than at almost any similar period in the past 11,400 years (Hathaway, 2004; Solankiet al., 2005); nor the consequent surface «global warming» on Mars, Jupiter, Neptune's largest moon, and even distant Pluto; nor the eerily - continuing 2006 solar minimum; nor the consequent, precipitate decline of ~ 0.8 °C in TS from January 2007 to May 2008 that has canceled out almost all of the observed warming of the 2Multidecadal Oscillation, or the Pacific Decadal Oscillation that has recently transited from its warming to its cooling phase (oceanic oscillations which, on their own, may account for all of the observed warmings and coolings over the past half - century: Tsoniset al., 2007); nor the magnitude nor duration of multi-century events such as the Mediaeval Warm Period or the Little Ice Age; nor the cessation since 2000 of the previously - observed growth in atmospheric methane concentration (IPCC, 2007); nor the active 2004 hurricane season; nor the inactive subsequent seasons; nor the UK flooding of 2007 (the Met Office had forecast a summer of prolonged droughts only six weeks previously); nor the solar Grand Maximum of the past 70 years, during which the Sun was more active, for longer, than at almost any similar period in the past 11,400 years (Hathaway, 2004; Solankiet al., 2005); nor the consequent surface «global warming» on Mars, Jupiter, Neptune's largest moon, and even distant Pluto; nor the eerily - continuing 2006 solar minimum; nor the consequent, precipitate decline of ~ 0.8 °C in TS from January 2007 to May 2008 that has canceled out almost all of the observed warming of the 20th century.

And finally, attribution studies can't simply rely on model simulations, since model simulations (even if they capture the correct spectrum of variability) won't match the observed realization of the multidecadal modes in terms of timing.

Observed Atlantic major hurricane frequency has exhibited pronounced multidecadal variability since the 1940s.

The observed internal variability so estimated exhibits a pronounced multidecadal mode with a distinctive spatiotemporal signature, which is altogether absent in model simulations.

This model's forced response agrees very well with the observed surface temperatures averaged over the North Atlantic, so in this model one doesn't need to invoke internal multidecadal variability to match these observations.