Sentences with phrase «natural multidecadal oscillation»

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).

[Rob P]- The warming from 1910 - 1940, a time of weak anthropogenic (human - caused) forcing, matches the warm (positive) phase of the Interdecadal Pacific Oscillation (IPO)- the largest natural multidecadal oscillation in the climate system.

Not exact matches

Researchers from the University of California Irvine have shown that a phenomenon known as the Atlantic Multidecadal Oscillation (AMO)-- a natural pattern of variation in North Atlantic sea surface temperatures that switches between a positive and negative phase every 60 - 70 years — can affect an atmospheric circulation pattern, known as the North Atlantic Oscillation (NAO), that influences the temperature and precipitation over the Northern Hemisphere in winter.

Natural changes like the Atlantic Multidecadal Oscillation as well as more familiar shifts like El Niño are responsible for some of the year - to - year fluctuations in the number of hurricanes.

The Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO), and El Niño - Southern Oscillation (ENSO) have all been found to significantly influence changes in surface air temperature and rainfall (climate) on decadal and multi-decadal scales, and these natural ocean oscillations have been robustly connected to changes in solar activity.

NOAA has issued its annual forecast for the hurricane season, along with its now - standard explanation that there is a natural cycle of multidecadal (40 - 60 year) length in the North Atlantic circulation (often referred to as the «Atlantic Multidecadal Oscillation» — see Figure), that is varying the frequency of Atlantic tropical cyclones, and that the present high level of activity is due to a concurrent positive peak in this multidecadal (40 - 60 year) length in the North Atlantic circulation (often referred to as the «Atlantic Multidecadal Oscillation» — see Figure), that is varying the frequency of Atlantic tropical cyclones, and that the present high level of activity is due to a concurrent positive peak in this Multidecadal Oscillation» — see Figure), that is varying the frequency of Atlantic tropical cyclones, and that the present high level of activity is due to a concurrent positive peak in this oOscillation» — see Figure), that is varying the frequency of Atlantic tropical cyclones, and that the present high level of activity is due to a concurrent positive peak in this oscillationoscillation.

In the 1930s, warming was localised to the high latitudes, consistent with this warming being the result of a natural oscillation (the so - called «Atlantic Multidecadal Oscillatioscillation (the so - called «Atlantic Multidecadal OscillationOscillation»).

Another natural climate swing, called the Atlantic Multidecadal Oscillation, also contributes to the intensification of monsoon rainfall.

Specifically, the claim was made that temperatures in Churchill, Manitoba (close to the center of the Western Hudson Bay population of bears) had not risen, and that instead, any multidecadal variations in temperatures affecting the bears were related to the Arctic Oscillation (AO), a mode of natural variability.

There is a natural variable I did not account for in this post, and it is the Atlantic Multidecadal Oscillation, or AMO.

However the natural climate is always changing due to cycles of the sun, ocean oscillations like El Nino and the Atlantic Multidecadal Oscillation that alter the direction and strength of the winds, or natural landscape successions.

This is the type of variability that comes from natural interactions between the ocean and the atmosphere (i.e., that due to phenomena like the El - Nino / Southern Oscillation or perhaps the Atlantic Multidecadal Oscillation).

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.

e.g. there is 1) a mild global cooling from the Holocene Climatic Optimum 2) A millenial scale oscillation of ~ 1500 years per Loehle & Singer above (i.e. an approximately linear rise from the Little Ice Age — or better an accelerating natural warming since the LIA) 3) A 50 - 60 year multidecadal oscillation.

They found that between 5 % and 30 % of the Arctic sea ice decline from 1979 to 2010 could be attributed to the natural cycles of the Atlantic Multidecadal Oscillation (AMO) and Arctic Oscillation (AO), and even less can be attributed to natural cycles since 1953, since these natural cycles tend to average out over longer timeframes (as Vinnikov also found).

In its end of February report, the US National Snow and Ice Data Center (NSIDC) noted that Barents Sea ice was below average for this time of year (see Fig. 1 above, and Fig. 5 below) but suggested this was primarily due to natural variation driven by the Atlantic Multidecadal Oscillation (AMO):

I'm not a climate scientist, but I would have considered it good science to understand the effects of each of the major natural changes that are known to affect global temperatures, including the multidecadal ocean oscillations, long before I started looking at any anthropogenic effects.

The Atlantic multidecadal oscillation (AMO), a 60 - to -80-year natural cycle in sea surface temperature, explained less than 0.1 degrees Celsius [0.2 degrees Fahrenheit] of the rise, according to Trenberth.

Recent analyses show similar northward fish migrations are associated with intruding warm Atlantic waters, driven by natural shifts in the North Atlantic Oscillations and Atlantic Multidecadal Oscillation.

This hemisphere difference is further amplified over European - African longitudes due to both natural (Atlantic Multidecadal Oscillation) and anthropogenic factors (decreased aerosol pollution over Europe following stricter environmental measures)-- both explained in more detail in our Sahel greening article.

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

Natural variables like the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO) are cited as the causes for these variations.

The near - linear rate of anthropogenic warming (predominantly from anthropogenic greenhouse gases) is shown in sources such as: «Deducing Multidecadal Anthropogenic Global Warming Trends Using Multiple Regression Analysis» «The global warming hiatus — a natural product of interactions of a secular warming trend and a multi-decadal oscillation» «The Origin and Limits of the Near Proportionality between Climate Warming and Cumulative CO2 Emissions» «Sensitivity of climate to cumulative carbon emissions due to compensation of ocean heat and carbon uptake» «Return periods of global climate fluctuations and the pause» «Using data to attribute episodes of warming and cooling in instrumental records» «The proportionality of global warming to cumulative carbon emissions» «The sensitivity of the proportionality between temperature change and cumulative CO2 emissions to ocean mixing»

Moreover, 370 years of tropical cyclone data from the Lesser Antilles (the eastern Caribbean island chain that bisects the main development region for landfalling U.S. hurricanes) show no long - term trend in either power or frequency but a 50 - to 70 - year wave pattern associated with the Atlantic Multidecadal Oscillation, a mode of natural climate variability.

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.»

The warming and cooling cycles in the Arctic have nothing at all to do with global warming, but follow the Atlantic Multidecadal Oscillation, a perfectly natural event, which NOAA says has been occurring for at least the last 1000 years.

Judith's point that AO and PO oscillations and multidecadal waves which may go in 60, 80 or 100 year cycles is completely ignored by saying that Natural variation should be ignored over a long time as it reverts to the mean.

This Atlantic Multidecadal Oscillation (AMO) is a natural cycle that has existed for at least the last 1,000 years, but has assuredly been around much longer than that.

What was done, was to take a large number of models that could not reasonably simulate known patterns of natural behaviour (such as ENSO, the Pacific Decadal Oscillation, the Atlantic Multidecadal Oscillation), claim that such models nonetheless accurately depicted natural internal climate variability, and use the fact that these models could not replicate the warming episode from the mid seventies through the mid nineties, to argue that forcing was necessary and that the forcing must have been due to man.

Scientists have dubbed this natural cycle the «Atlantic Multidecadal Oscillation,» or AMO, and since ocean temperatures have been on the upswing for the past decade, so too has hurricane activity.

We show that a harmonic constituent model based on the major astronomical frequencies revealed in the aurora records and deduced from the natural gravitational oscillations of the solar system is able to forecast with a reasonable accuracy the decadal and multidecadal temperature oscillations from 1950 to 2010 using the temperature data before 1950, and vice versa.

This mean that 0.2 — 0.08 = 0.12 deg C per decade warming is due to the multidecadal oscillation, which is natural.

By claiming the multidecadal oscillation does not exist and claiming the warming due to this natural warming from 1970 - 2000 is man made.

Wu et al. (7, 8) pointed out the importance of this mode in the modern global temperature record with a period of 65 y: If it is interpreted as natural and related to the Atlantic Multidecadal Oscillation (AMO)(9 ⇓ ⇓ — 12), then the trend attributed to anthropogenic warming should be significantly reduced after ∼ 1980, when the AMO was in a rising phase.

A debate concerns the nature of these increases with some studies attributing them to a natural climate fluctuation, known as the Atlantic Multidecadal Oscillation (AMO), and others suggesting climate change related to anthropogenic increases in radiative forcing from greenhouse - gases.

This interest in natural variability led to an irony: one of Mann's first papers, a collaboration with Jeffrey Park, provided evidence for the existence of a natural cycle, the Atlantic Multidecadal Oscillation, or AMO.

Whereas each model demonstrates some sort of multidecadal variability (which may or may not be of a reasonable amplitude or associated with the appropriate mechanisms), the ensemble averaging process filters out the simulated natural internal variability since there is no temporal synchronization in the simulated chaotic internal oscillations among the different ensemble members.

That leaves the North Atlantic, but it has another mode of natural variability called the Atlantic Multidecadal Oscillation...... which is why it doesn't cool between the strong El Niños.

Never mind the fact that those same models were unable to reproduce large scale natural climate variability such as the Pacific Decadal Oscillation, the Atlantic Multidecadal Oscillation and ENSO.