Cross-equatorial jet streams: what is “normal” behavior?

After the two videos about the “tearing apart” of the Washington Post article, Beckwith seemed to have found more unusual jet stream behavior and made another video: More Mangled Jet Stream Behaviour.

He first lectured that in theory there are four distinct jet streams, two in each hemisphere, but then he claimed that in practice this is not the case (anymore). That is all nice and well, but a first question would be: do those jet streams behave as theory in the first place? These are all working in a complex, coupled and chaotic system that is our climate system, so I would espect that they wouldn’t necessarily follow the ideal path.

A second question would be whether these jet streams behaved as in the theory in the past? If yes, since when did this behavior changed?

He went back to the Earth nullschool app and dialed in on winds at 250 mbar. He found these dates with “mangled” jet stream behavior:

  • December 21, 2015
  • December 9, 2014
  • December 14, 2013.

Then he starts back in 2015 for apparently another round:

  • February 10, 2015
  • February 1, 2014
  • February 5, 2014.

After this, he pointed to some Monsoonal flows (which he now seems to consider as normal behavior). That seemed odd, why didn’t he continue the list of unusual cross-equatorial flows with 2013, as he did in his first round? Was there no mangled jet stream behavior in February 2013?

These were these Monsoonal flows:

  • July 7, 2014
  • June 23, 2015.

There seem to be a pattern here. The monsoonal flows he found happened in June-July. That made sense. He also found two monsoonal flows at the end of June 2016. But strangely enough no mention of such an event in say June or July 2013.

The unusual cross-equatorial flows he mentioned all occurred in December and February. If these are the only instances that he found, then I would be very curious what exactly happens in December and in February that could result in such flows?

He ends with the puzzling conclusion:

In summary: we need to go further back in time to relate this behavior of the jet stream to the sea ice and snow cover loss. Because the Arctic is warming rapidly, so the jets are changing correspondingly.

That is an odd statement. He seemed to be really sure about the link, yet now he says that we have to go further back to establish that relationship. Why didn’t he just do that before all this?

So I thought it would be a good idea to just go to Earth nullschool and go back in time. First I wanted to go back to February 2013 to see whether the jet stream was still mangled and then later to 2012 and so on until I got to “normal” behavior. When I went to February 2013 I got this message:

no data-message

So I went to March 2013: the same, no data. April 2013: still no data. The first date for which there was data is November 1, 2013.

November 1, 2013!

That is a whopping 2.5 year worth of data. He OF COURSE needs to go back further in time. With only 2.5 years of data, how could he ever know what the “normal” state of those jet streams is compared to the instances he now found? Let alone when it changed and how they are related to the Arctic melt.


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