New paper finds natural ocean oscillations responsible for record cold US winter, not CO2
http://hockeyschtick.blogspot.com/2014/04/new-paper-finds-natural-ocean.html
A new paper published in Environmental Research Letters finds the natural ocean oscillations the Atlantic Multidecadal Oscillation [AMO] and the North Atlantic Oscillation [NAO] may be responsible for the recent resurgence of record cold extreme temperatures in the Eastern US and Europe, and that extreme cold winters in these regions will persist as long as the AMO remains positive. The AMO shifted from negative to positive around the year 2000, along with the “pause” in global warming. A typical AMO cycle lasts ~60-70 years, and thus the current positive phase of the AMO and extreme cold US winters could occur for another ~18 or so years. According to the authors, “Our statistical analyses suggest that the AMO signal precedes the NAO by 10–15 years with an interesting predictability window for decadal forecasting… As in observations, the positive phase of the AMO results in more frequent negative NAO—and blocking episodes in winter that promote the occurrence of cold extreme temperatures over the eastern United States and Europe. Thus, it is plausible that the AMO plays a role in the recent resurgence of severe winter weather in these regions and that wintertime cold extremes will be promoted as long as the AMO remains positive.”
Warmists such as Jennifer Francis have made the silly claim that the record US cold winter was due to man-made global warming causing jet stream blocking, but this paper and many others prove natural cycles are responsible, not CO2.
AMO index with a Fourier analysis showing a cycle length of ~60-70 years. The AMO shifted to the positive phase [above zero] around the beginning of the 20th century, so the positive phase has another ~18 or so years to go.
Wavelet analysis shows predominant periodicity of AMO is ~64 years. How to read wavelet analyses.
Forcing of the wintertime atmospheric circulation by the multidecadal fluctuations of the North Atlantic ocean
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Yannick Peings and Gudrun MagnusdottirTag this article PDF (3.18 MB) View articleThe North Atlantic sea surface temperature exhibits fluctuations on the multidecadal time scale, a phenomenon known as the Atlantic Multidecadal Oscillation (AMO). This letter demonstrates that the multidecadal fluctuations of the wintertime North Atlantic Oscillation (NAO) are tied to the AMO, with an opposite-signed relationship between the polarities of the AMO and the NAO. Our statistical analyses suggest that the AMO signal precedes the NAO by 10–15 years with an interesting predictability window for decadal forecasting. The AMO footprint is also detected in the multidecadal variability of the intraseasonal weather regimes of the North Atlantic sector. This observational evidence is robust over the entire 20th century and it is supported by numerical experiments with an atmospheric global climate model. The simulations suggest that the AMO-related SST anomalies induce the atmospheric anomalies by shifting the atmospheric baroclinic zone over the North Atlantic basin. As in observations, the positive phase of the AMO results in more frequent negative NAO—and blocking episodes in winter that promote the occurrence of cold extreme temperatures over the eastern United States and Europe. Thus, it is plausible that the AMO plays a role in the recent resurgence of severe winter weather in these regions and that wintertime cold extremes will be promoted as long as the AMO remains positive.
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