Wintry questions

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Subfreezing

Wintry questions

Post #1 by Subfreezing » Tue Nov 06, 2012 9:41 pm

Hi, I have a few questions sorry; not sure whether I should post them at once or in separate posts. I’ll list them here:

1) Why, when the Arctic Oscillation (AO) index is quite positive and the North Atlantic Oscillation (NAO) index only weakly negative, have we a “Greenland block” at the moment, which is set to intensify within the next few days?

http://www.metoffice.gov.uk/weather/uk/ ... ssure.html (updates regularly, so may not illustrate my point).

Is this related to the Arctic Dipole anomaly, which is allegedly at a record strength this year?

http://farm9.staticflickr.com/8458/7993 ... 26ce_o.jpg

from http://neven1.typepad.com/blog/2012/10/ ... a-ice.html

2) Is it possible that an Artctic Oscillation index which is extremely negative may actually impede, not encourage, the movement of low pressure systems through to the north of Greenland and down to Europe due to the abundance of high pressure systems over north- eastern Canada, and instead, divert the jet stream over the south of Greenland (and down and across to Europe) to produce cold but not very cold, winters? I ask this because during the winter of 1968/69, the AO and NAO indices were very negative at the same time, yet that winter was not spectacular.

3) To what extent does the Arctic Dipole “replace”, and how, the AO and NAO, as is suggested in the following link?

http://en.wikipedia.org/wiki/Arctic_dipole_anomaly

Thanks to anyone who’s able to answer one of more of these questions!


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