StratoBendigo wrote: ↑Sat Jul 20, 2019 4:42 pm
Petros wrote: ↑Fri Jul 19, 2019 7:02 pm
Interesting Crickey/Didg
The lack of sub polar jet under Aus is a very pertinent observation imo.
It makes me wonder if the Indian Ocean surface temp anomalies are having an impact? Ie. Warm central Indian Ocean pushing subtropical jet Southwards.
Hi 'stratobendigo'.
Thanks for joining the conversation
Firstly.,Trying to find information about jetstreams in the SH is very hard .Its always the NH that is mostly found in the literature.
I would expect the dynamics are somewhat similar, except we have a vast expanse of sea in the SH and l believe it makes our jets less prone to massive waves like they get in the NH from temp land and ocean contrasts.
That makes you comment regarding sea surface temps' more intriguing. Surely the ocean temps have a significant role
One quote from credible source
'Why is jet stream so far south?
In the winter the polar jet moves south and becomes stronger because the North Pole gets colder but the equator stays about the same temperature. This increases the temperature contrast and moves the strengthened polar front jet farther south.
https://climate.ncsu.edu/edu/JetStream
From that comment one assumes that the jets being south for winter is a regular event.
Just a point of interest.20th July 2019today.
Today surface temp' gradient from the sth pole to melbourne (using ACC G model)
SOUTH POLE -60DEG C ....10am
melbourne about 10deg c
Temp gradient difference 70deg c
....
Melbourne to the equator
Melbourne 10deg c
Equator at similar longitude 28deg c
temp gradient difference =18deg c
Pole to equator temp' difference -60 .....+28 = 88 deg c
and so we can look at that temp' gradient this summer and see the difference in position of sub tropical jet , l suppose
quote
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