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Impressive 4 SD DJFM AO Streak Since 2009


bluewave

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We just extended the current 4 SD AO streak to 8 DJFM's in a row. This surpasses the previous 6 year streak from 75-76 to 80-81.

 

Peak DJFM AO values reaching 4SD or more since 1960:

16-17...12/21...+4.600

15-16...12/22...+4.503....1/16...-4.898

14-15...3/8/15..+5.588

13-14...12/15...+4.303

12-13....3/20....-5.588

11-12...12/2....+4.350

10-11...12/18...-5.265

09-10..12/21....-5.821

 

07-08...1/24....+4.598

 

04-05...1/5...+4.703....2/26...-4.337

03-04...1/17...-4.387

 

00-01...1/25....-4.854

 

97-98...1/10...-4.269

 

95-96...12/19...-4.353

 

92-93...1/14...+5.245

91-92...12/17..+4.704

 

89-90...2/26...+5.911

88-89...1/14...+5.582

 

85-86...3/23....+4.253

84-85...1/19.....-6.226

83-84...12/27...+4.460

82-83...1/18....+4.426

 

80-81...3/4.....-4.313

79-80..12/2...+5.040

78-79...1/25...-4.387

77-78...2/5....-5.921...3/20...+4.180

76-77...1/15...-7.433

75-76...2/25..+4.172

 

69-70...3/5....-6.365

68-69...2/13..-5.282

67-68...3/16..+4.917

 

65-66...1/28...-5.130

 

62-63...1/21...-5.010

61-62...3/14...-4.417

 

59-60..1/28...-4.108

 

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Very interesting data. Unfortunately, the not all (and probably most) variables that lead to extreme AO outcomes are not well understood, so it's difficult to be sure whether the current stretch is unusual or within the bounds of internal variability.

It may be plausible that Arctic Amplification might be contributing to a higher likelihood of extremes in recent years, but that remains little more than a hypothesis, especially as the AO's internal variability is high. A number of the above extreme cases coincided with or followed abnormally high Arctic temperatures, but there were exceptions. Such warmth might be a precursor or at least precondition the atmosphere to increase the probability of such extremes. That, too, is little more than a hypothesis.

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10 hours ago, donsutherland1 said:

Very interesting data. Unfortunately, the not all (and probably most) variables that lead to extreme AO outcomes are not well understood, so it's difficult to be sure whether the current stretch is unusual or within the bounds of internal variability.

It may be plausible that Arctic Amplification might be contributing to a higher likelihood of extremes in recent years, but that remains little more than a hypothesis, especially as the AO's internal variability is high. A number of the above extreme cases coincided with or followed abnormally high Arctic temperatures, but there were exceptions. Such warmth might be a precursor or at least precondition the atmosphere to increase the probability of such extremes. That, too, is little more than a hypothesis.

Don, there was a study back in 2009 looking at NAO variability over 218 years using corals. It came to the conclusion that the NAO swings increased with warmer temperatures.

But we will probably need more data and studies to know if what we are experiencing is within the range on internal variability or not.

https://www.whoi.edu/page.do?pid=83537&tid=3622&cid=54686&c=2

Study links swings in North Atlantic Oscillation variability to climate warming

The research team found the variability of the NAO decade-to-decade (multi-decadal scale) has been larger, swinging more wildly, during the late twentieth century than in the early 1800s, suggesting that variability is linked to the mean temperature of the Northern Hemisphere. This confirms variability previously reported in past terrestrial reconstructions. 

“Anthropogenic (human-related) warming does not appear to be altering whether the NAO is in a positive or negative phase at multi-decadal time scales,” said WHOI paleoclimatologist Konrad Hughen. “It does seem to be increasing variability. Clearly, this has implications for the future.”

“As temperatures get warmer, there’s potential for more violent swings of the NAO — the phases becoming even more positive and even more negative,” Hughen added. “If the NAO locks more into these patterns, intense storms will become more intense and droughts will become more severe.” 

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16 hours ago, bluewave said:

Don, there was a study back in 2009 looking at NAO variability over 218 years using corals. It came to the conclusion that the NAO swings increased with warmer temperatures.

But we will probably need more data and studies to know if what we are experiencing is within the range on internal variability or not.

https://www.whoi.edu/page.do?pid=83537&tid=3622&cid=54686&c=2

Study links swings in North Atlantic Oscillation variability to climate warming

The research team found the variability of the NAO decade-to-decade (multi-decadal scale) has been larger, swinging more wildly, during the late twentieth century than in the early 1800s, suggesting that variability is linked to the mean temperature of the Northern Hemisphere. This confirms variability previously reported in past terrestrial reconstructions. 

“Anthropogenic (human-related) warming does not appear to be altering whether the NAO is in a positive or negative phase at multi-decadal time scales,” said WHOI paleoclimatologist Konrad Hughen. “It does seem to be increasing variability. Clearly, this has implications for the future.”

“As temperatures get warmer, there’s potential for more violent swings of the NAO — the phases becoming even more positive and even more negative,” Hughen added. “If the NAO locks more into these patterns, intense storms will become more intense and droughts will become more severe.” 

Thank you very much. I look forward to reading the paper.

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