Is there a ‘shape’ to atmospheric circulation during low solar periods?

image

Based on a comment over at Weather Action

I’ve been looking into the 76/77 N hemisphere winter as well. Steven Goddard flagged up the similarities with this past winter & how the shape of the polar vortex was like theshape of the Laurentide ice sheet which sat over NAmerica during the Younger Dryas (including Alaska being ice free). Interestingly there was a tongue of sea extending this year off the coast of Labrador & Newfoundland. The winter that followed in 77/78 was notable indeed. I’m gathering more detail for a post, but it’s made me wonder is this the ‘shape’ of lower solar activity?

Piers Corbyn replied

Your+Steve Goddard’s point about the shape of that great Laurentide ice sheet which sat over N America in ‘the Younger Dryas’ period is very important. Question; was cold distribution in Maunder and Dalton similar or not?

The Maunder period will be difficult to infer due to the sparse records on both sides of the Atlantic but a fair degree of work has been done by the likes of Lamb. Things do improve by the Dalton onwards. This is the start of a few posts to investigate a possible shape

of low solar activity, that is a change in the shape of the upper air circulation.

“The late Prof HH Lamb, a world renowned climatologist, investigated the impact of the Little Ice Age on Scotland for part of his book Climate History and the Modern World. He wrote of arctic ice expanding further south and of reports of Inuit people arriving on Orkney between 1690 and 1728. One was said to have paddled down the River Don in Aberdeen. Snow remained all year round on the tops of mountains, including the Cairngorms…With weather patterns disrupted, fierce were winds battered the land.”

http://news.bbc.co.uk/1/hi/scotland/highlands_and_islands/8010513.stm
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This period was also characterized by an anomalous winter atmospheric circulation over the circum-Atlantic region in the form of a tri-pole pattern.

Reconstructions of winter sea-level pressure (SLP) indicate that over Europe an anomalous low was found over the Balkan area and an anomalous high just south of Iceland (Luterbacher et al.,
2002). Over eastern North America, somewhat east of the Hudson bay, an anomalous low was found extending into the subtropics (Lamb and Johnson, 1959; van der Schrier and Barkmeijer, 2005). This latter low deepens the existing trough in SLP over the Newfoundland- Labrador area.

The Gulf Stream and Atlantic sea-surface temperatures in AD1790–1825

G. van der Schrier* and S. L. Weber

International Journal of Climatology

Volume 30, Issue 12, October 2010

http://onlinelibrary.wiley.com/doi/10.1002/joc.2027/full

The following images reflect mean pressure values (see second image for key).
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Note on images. These are all taken from “On the nature of certain climactic epochs which differed from the modern (1900-39) normal” H.H.Lamb published in 1963 and reproduced in “The Changing Climate. Selected Papers” (1963) Routledge Revivals.

In the next a later post I’ll take a closer look at 1976/7, before returning to earlier periods LIA periods again.

This will be hosted at the WeatherAction News Blog

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One thought on “Is there a ‘shape’ to atmospheric circulation during low solar periods?

  1. Pingback: Today We See Clearly How Super Cold Over Hudson Bay Leads To Ice Ages | WeatherAction News

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