.... in another thread, the impact that events occurring in the
stratosphere have on the troposphere is discussed. A question was
raised as to whether there was recent research on all this. I've used
the search facility here ....

http://www.metoffice.gov.uk/corporat...catalogue.html

using the phrase:- "Sudden Stratospheric Warming"

Search found ... 103 titles.

I have extracted the titles of those which appear to be relevant to
impacts of such events on the troposphe-
[latest first/cut-off 1982]

Dynamical response of low-latitude middle atmosphere to major sudden
stratospheric warming events
Sathishkumar, S.
Journal of Atmospheric and Solar-Terrestrial Physics, VOL. 71 NO. 8/9,
2009

Blocking precursors to stratospheric sudden warming events
Martius, O.
Geophysical Research Letters, VOL. 36 NO. 14, 2009

Planetary wave breaking and tropospheric forcing as seen in the
stratospheric sudden warming of 2006
Coy, L.
Journal of the Atmospheric Sciences, VOL. 66 NO. 2, 2009

Is there a statistical connection between stratospheric sudden warming
and tropospheric blocking events?
Taguchi, M.
Journal of the Atmospheric Sciences, VOL. 65 NO. 4, 2008

Effect of stratospheric sudden warming and vortex intensification on
the tropospheric climate
Kuroda, Y.
Journal of Geophysical Research (Atmospheres), VOL. 113 NO. D15, 2008

The possible influence of stratospheric sudden warming on East Asian
Weather
Deng, S.
Advances in Atmospheric Sciences, VOL. 25 NO. 5, 2008

What kind of stratospheric sudden warming propagates to the
troposphere?
Nakagawa, K.I.
Geophysical Research Letters, VOL. 33 NO. 4, 2006

Influence of stratospheric sudden warming on the equatorial
troposphere
Kodera, K.
Geophysical Research Letters, VOL. 33 NO. 6, 2006

The impact of the stratosphere on the troposphere during the southern
hemisphere stratospheric sudden warming, September 2002
Charlton, A.J.
Quarterly Journal of the Royal Meteorological Society, VOL. 131 NO.
609, 2005

A mechanistic model study of slowly propagating coupled
stratosphere-troposphere variability
Kodera, K.
Journal of Geophysical Research (Atmospheres), VOL. 105 NO. D10, 2000

Tropospheric circulation changes associated with stratospheric sudden
warmings: a case study
Kodera, K.
Journal of Geophysical Research (Atmospheres), VOL. 100 NO. D 6, 1995

The quasi-biennial oscillation and major stratospheric warmings: a
three-dimensional model study
Dameris, M.
Annales Geophysicae, VOL. 8 NO. 2, 1990

Planetary waves modulated by the quasi-biennial oscillation (QBO)
Maillard, A.
Annales Geophysicae, VOL. 8 NO. 7/8, 1990

Sudden stratospheric warming and anomalous U.S. weather
Douglas, D.A.
Monthly Weather Review, VOL. 116 NO. 1, 1988

A numerical test of connections between the stratospheric sudden
warming and the quasi-biennial oscillation
Bridger, A.F.C.
Journal of Geophysical Research (Atmospheres), VOL. 89 NO. D3, 1984

----- artificial cutoff at 1982 ----

And of course, these couplings have been studied by researchers in
Russia, Japan, China and France, to name but four, and to do an
exhaustive search would require looking for works published in those
languages - it has been an 'active' area of research over the last 10
years or so.

A word of caution: don't rely on a 'general' internet search for this
type of subject: you need to interrogate specialised catalogues, such
as this one, or the AMS etc.

Martin.


--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

On Dec 12, 12:16*pm, "Martin Rowley"
wrote:

Martin, you are an absolute star. I really appreciate the effort
involved. I didn't know that catalogue existed and it is now
bookmarked and will provide lots of future reading, as well as a good
hour's initial dipping in. I've cut down much, extracted some main
points from the most recent first and I've added my own summaries
FWIW:

Dynamical response of low-latitude middle atmosphere to major sudden
stratospheric warming events
Sathishkumar, S.
Journal of Atmospheric and Solar-Terrestrial Physics, VOL. 71 NO. 8/9,
2009

The UKMO zonal mean zonal winds at 60°N show a short-term reversal to
westward winds in the entire upper stratosphere and lower mesosphere
and the low-latitude winds (8.75°N) show enhanced eastward flow in the
upper stratosphere and strong westward flow in the lower mesosphere
during the major SSW events at high latitudes. The mesosphere and
lower thermosphere (MLT) zonal winds acquired by medium frequency (MF)
radar at Tirunelveli (8.7°N, 77.8°E) show a change of wind direction
from eastward to westward several days before the onset of SSW events
and these winds decelerate and weak positive (eastward) winds prevail
during the SSW events.

Not really UK based and I'd read about the reversal of stratospheric
winds prior to SSW events.

Blocking precursors to stratospheric sudden warming events
Martius, O.
Geophysical Research Letters, VOL. 36 NO. 14, 2009

The primary causes for the onset of major, midwinter, stratospheric
sudden warming events remain unclear. In this paper, we report that 25
of the 27 events objectively identified in the ERA-40 dataset for the
period 1957–2001 are preceded by blocking patterns in the troposphere.
The spatial characteristics of tropospheric blocks prior to sudden
warming events are strongly correlated with the type of sudden warming
event that follows

Particular patterns of tropospheric blocking may precede SSWs but
there's little in this to help with forecasting UK surface conditions

Planetary wave breaking and tropospheric forcing as seen in the
stratospheric sudden warming of 2006
Coy, L.
Journal of the Atmospheric Sciences, VOL. 66 NO. 2, 2009

Results also show that the anticyclonic development, initiated by the
subtropical wave breaking and associated with the poleward advection
of the low PV values, occurred over a limited altitude range of
approximately 6-10 km. The authors also show that the poleward
advection of this localized low-PV anomaly was associated with changes
in the Eliassen-Palm (EP) flux from equatorward to poleward,
suggesting an important role for Rossby wave reflection in the SSW of
January 2006. Similar upper tropospheric forcing and subtropical wave
breaking were found to occur prior to the major SSW of January 2003.

Doesn't help in specific UK forecasting, except to reinforce what Will
said about SSWs influencing Rossby wave development. I was aware of
that.

Is there a statistical connection between stratospheric sudden warming
and tropospheric blocking events?
Taguchi, M.
Journal of the Atmospheric Sciences, VOL. 65 NO. 4, 2008

[23] This study, based upon the ERA-40 data set, reveals
a clear linkage between major SSW events and blocks, with
the former being almost always preceded by the latter.
Separate composites compiled for displacement and splitting
SSW events indicate that displacement events are
associated with block occurrence in the eastern North
Atlantic, and splitting events associated with either the
occurrence of blocks in the eastern North Pacific or the
contemporaneous occurrence of blocks in the eastern North
Pacific and the North Atlantic.

[25] These results might, at first sight, be difficult to
reconcile with a recent study by Taguchi [2008], who
suggested that there is no statistically significant connection
between SSW events and tropospheric blocks. The apparent
contradiction is, however, easily resolved by noting that
most of the analysis in that study was done using 500 hPa
fields. As we have shown (cf. Figure 2) the wave amplitudes
at that level are very weak, and one needs to look at
200 hPa or above for clear signals to emerge.

I'd read the original 2008 paper by Taguchi. It was one of the main
factors in my holding the views that I expressed earlier. fascinating
to see the progression in the research. An obvious link to
tropospheric blocks and a real possibility for use in future UK
forecasting.

Effect of stratospheric sudden warming and vortex intensification on
the tropospheric climate
Kuroda, Y.
Journal of Geophysical Research (Atmospheres), VOL. 113 NO. D15, 2008

Couldn't find, it, pity.

The possible influence of stratospheric sudden warming on East Asian
Weather
Deng, S.
Advances in Atmospheric Sciences, VOL. 25 NO. 5, 2008

By analyzing the linkage of the Northern Annular Mode (NAM) anomaly to
the East Asian jet and the East Asian trough during Stratospheric
Sudden Warming (SSW), the influence of SSW on East Asian weather is
studied. The results show that the East Asian jet is strengthened and
the East Asian trough is deepened during SSW. With the downward
propagation of SSW, the strengthened East Asian jet and the East Asian
trough would move southward, expand westward and gradually influence
the area of north and northeastern China. This implies that the winter
monsoon tends to be enhanced over East Asia during SSW.

Not UK, but a very interesting summary! I certainly didn't know about
the link to the East Asian winter monsoon.

What kind of stratospheric sudden warming propagates to the
troposphere?
Nakagawa, K.I.
Geophysical Research Letters, VOL. 33 NO. 4, 2006

Requires subscription. Couldn't find it elsewhere.

Influence of stratospheric sudden warming on the equatorial
troposphere
Kodera, K.
Geophysical Research Letters, VOL. 33 NO. 6, 2006

Not enoughy of a UK use.

The impact of the stratosphere on the troposphere during the southern
hemisphere stratospheric sudden warming, September 2002
Charlton, A.J.
Quarterly Journal of the Royal Meteorological Society, VOL. 131 NO.
609, 2005

Stratospheric sudden warmings are the clearest and strongest
manifestation of dynamical coupling in the stratosphere–troposphere
system..............Major midwinter stratospheric sudden warmings are
found to occur with a frequency of approximately six events per
decade, and 46% of warming events lead to a splitting of the
stratospheric polar vortex.

Not a clear link to UK weather, but we have a split polar vortex at
present, which is helping this UK cold event to take place (not to do
with SW, though the stratosphere is beginning to warm). A less than
50% occurrence, but nevertheless possibly significant for future UK
forecasting.

The other articles are pre 1995. I'd rather see some more of the more
recent publications.

Really interesting. I said before; "Research shows tentative links,
but that's all they are. Maybe future research will bring stratosheric
warming more into mainstream forecasting of the onset of colder
conditions in a UK winter. I wouldn't rule it out, but neither would I
go anything like as far as "often"! I also said this, in response to
Will: "I feel the same about events in the stratosphere affecting
surface conditions, Will, as I've said. There are links and I'm
convinced that these affect surface conditions.

I'd still, after scan-reading these papers and fully reading the
abstracts, not go with "fully", however, reading these has widened my
understanding and reinforced my original beliefs that SSWs affect
surface conditions. I still don't, however, feel that SSWs can be used
"often" to forecast surface conditions in the UK, but as I've said
several times and with restraint and politeness in the face of some
pretty fierce and incorrect criticism and questioning, I would be very
interested in finding out more

Thank you again for the link Martin and I hope my summaries are
helpful to others. *))

Following my own advice, I had a look at the AMS site, and came up
with this which I found useful:-

http://ams.confex.com/ams/17Fluid15M...per_153709.htm

[ Unfortunately it needs to load some additional software to read it,
but it's worth persevering! [ I note, BTW, that the TWO board has been
discussing this, so it may not be new to some here. ]

[Summary]
... Conference held in June 2009 (and discussed the event of early
2009/February 16th on)

... Two categories of stratospheric polar vortex anomaly: displacement
(single centre/shunted to one side), and split (two centres, one
usually dominant).

... The split vortex is more likely to propagate influence to
troposphere.

... Both events/SSW - +ve ht anoms polar regions (c.f. -ve AO)

... However, split events (such as the one discussed, and the one we
have currently) have effect over greater number of defined longitude
bands - greatest impact Europe/Asia.

... With the specific event (start~16th Jan, 2009) rapid switch
from -ve temp/ht anoms to +ve temp/ht anoms, propagating downwards
through lower stratosphere/upper troposphere within period of 24-48
hrs, but delayed to lower troposphere to around +96/+120hr.

... Then effect weakened again (at low levels).

And at the end of the presentation, the following slide concluded:-

1. Not all Sudden Stratospheric Warming events descend into the
troposphere.
2. The implied switch (or enhancement) of a -ve Arctic Oscillation
wasn't global or persistent (not sure what 'persistent' meant in this
context).
3. Many other factors were involved!

My reading of it all was that this was another 'tool' in the climate
forecasting armoury, but it wasn't a 'silver bullet' by any means.

For interest, I had a look at the events leading up to our recent
change of type, from the perspective of the 10 mbar level: charts
available on the University of Wyoming site
(http://weather.uwyo.edu/upperair/uamap.html)

And very roughly the sequence at this level was ...

+ Up to the end November '09:
Single vortex / hugging north 'shore' of Asian Russia/Siberia -
drifting slowly east under influence strong jet on southern flank.
High cell western Canada, initially strong, declining. Polar
temperatures this level MS75C or lower, small areas MS80C.

+ Early days December (to ~ 5th)
Single vortex / moving over and/or straddling polar region (heading
for Canada .. see below). Major Aleutian high formed. Strong (at least
190 knots) jet high-arctic Canada from west or NW. Temps broadly
similar across poles.

+ 6th - 9th December
The single vortex drifting across NE Greenland then Baffin Island then
to far N. Hudson Bay BUT, strong trough developing towards Novaya
Zemlya (NZ). Temperatures polar region MS85 or a shade colder -
possibly the coldest of this sequence.

+ 24hr up to end 10th
Split vortex achieved: main centre NW Canada, secondary NZ. Warming
across 'neck' between centres ~+5C
( It was, *very roughly* during this period that our 'local' pattern
changed from an 'Atlantic'/CW or CSW type to an A type, with a
meridional pattern in the central North Atlantic. )

+ Current (13/00Z)
Strongly split vortex / temperature change across pole (relative to
just before split) ~+10C. Marked ridging NE Atlantic region with
temperature change across the Iceland region (at this level) ~+15C.

These increases in temperature (and associated height changes) are
quite modest BTW, and certainly wouldn't be classified as 'major':
cases have been documented where temperatures at this level (10mbar)
go from -80C odd, to around 0C in a very short time!

Martin.


--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

Ideas of a stratospheric influence on tropospheric weather and climate
has been around for quite a while, and is currently undergoing a push
again. If you're interested in Strat-Trop coupling then a good place
to look for current research is on Dave Thompson's Annular Mode
website - there's a repository of papers there.
http://www.atmos.colostate.edu/ao/ResPapers/index.html

"rinceboy" wrote in message
...
Ideas of a stratospheric influence on tropospheric weather and
climate
has been around for quite a while, and is currently undergoing a
push
again. If you're interested in Strat-Trop coupling then a good place
to look for current research is on Dave Thompson's Annular Mode
website - there's a repository of papers there.
http://www.atmos.colostate.edu/ao/ResPapers/index.html


.... that's great, many thanks!

Martin.


--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

On Dec 14, 1:43*pm, "Martin Rowley"
wrote:
"rinceboy" wrote in message

...

Ideas of a stratospheric influence on tropospheric weather and
climate
has been around for quite a while, and is currently undergoing a
push
again. If you're interested in Strat-Trop coupling then a good place
to look for current research is on Dave Thompson's Annular Mode
website - there's a repository of papers there.
http://www.atmos.colostate.edu/ao/ResPapers/index.html

... that's great, many thanks!

Martin.

--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N * Long: 01.88W
NGR: SU 082 023

Excellent, I echo Martin's comments.

This one is very interesting and appears to be the paper that Adam
Scaife was referring to when I emailed him following a Times Article
he'd written linking the very wet weather of the summer of 2007 to La
Nina.

Dear Paul
We are still looking into this link. The main points are likely to be
written up into a journal paper with colleagues but are still being
investigated. In summary we do find a link between summer climate in
northernmost Europe and La Nina. A very similar pattern emerged in
seasonal forecasts for this summer and historical analyses. However,
it is only a contributing factor to the conditions this summer and
does not of course provide a full explanation. Sorry I can't provide
more information as yet, best Adam

(Adam said later that I could use his response on TWO, which is why I
reproduce it here).

The role of the stratosphere in the European climate response to El
Niño
S. Ineson & A. A. Scaife

El Niño/Southern Oscillation (ENSO) is the largest natural interannual
climate signal in the tropics; oscillations between warm El Niño and
cold La Niña phases occur every few years. The effects are felt not
only in the centre of action, the tropical Pacific region, but around
the globe. Observational studies show a clear response in European
climate to ENSO in late winter. However, the underlying mechanisms of
the link are not yet understood. Here we use a general circulation
model of the atmosphere, that has been extended into the upper
atmospheric layers, to provide end-to-end evidence for a global
teleconnection pathway from the Pacific region to Europe via the
stratosphere. We present evidence for an active stratospheric role in
the transition to cold conditions in northern Europe and mild
conditions in southern Europe in late winter during El Niño years. In
our experiments, this mechanism is restricted to years when
stratospheric sudden warmings occur. The response in European surface
climate to the El Niño signal is large enough to be useful for
seasonal forecasting.

Nature Geoscience 2, 32 - 36 (2009)
Published online: 7 December 2008 | doi:10.1038/ngeo381

The possible stratosphere link is very interesting. Not really SSWs,
but it stops me wondering where the research was!

Again, TY.

The possible stratosphere link is very interesting. Not really SSWs,
but it stops me wondering where the research was!

Again, TY.

Well the teleconnection from the Tropical Pacific to Europe in late
winter appears to be facilitated by
a stratospheric pathway - which is dependent on a frequency modulation
of SSW events. There are a few more papers on the ENSO-Stratosphere
pathway
in the literature which show that it is changes in stratospheric
variability (SSWs) which are important for the cold European response.