Stratosphere Temperature Watch 2015/2016

[Yarmy]

There have been tons of methods proposed for predicting future cycles. 45 separate ones are listed here for cycle 24:

http://users.telenet.be/j.janssens/SC24.html

In fact an official panel sits and makes a prediction:

http://legacy-www.swpc.noaa.gov/SolarCycle/SC24/Oct_2006.html

 It's a multi-million dollar question because insurance companies base their satellite premiums upon it.

Some methods have clearly been more successful than others (Svalgaard was very close). Amusingly, Dikpati who sits upon the panel predicted that SC24 would be one of the largest of the past 100 years:

http://zeenews.india.com/news/space/next-sunspot-cycle-to-be-3050-per-cent-stronger-scientists_280167.html

Oops. 

 

[Nouska]

I reckon De Jager and Duhau came closest as the only team to correctly predict early 2014 as maximum and SSN Rmax=68±17

http://www.sciencedirect.com/science/article/pii/S1364682608003787

A Dalton type is as far as they hypothesise.

I think I would agree with the view that we might need to wait another year but need to see what data looks like pre December 2016- do we even know whether this is a cumulative/residual effect in the declining phase or can it be 'washed out' with a longish period of very low activity?

This research group reckoned there was an even more enhanced positive NAO signature in the declining phase of even numbered solar cycles.

https://core.ac.uk/download/files/79/385447.pdf

[Interitus]

On 2/1/2016 at 8:49 AM, Recretos said:

What else to say. I was trying to be the voice of reason, to prevent euphoria due to misunderstanding of the strat dynamics, and to explain just how each event is different than others, and must be taken with an analytical approach across multiple layers and multiple parameters. For some time I was trying to emphasise just how important the height fields are. The event might be called stratospheric warming, but temperature on its own is not even nearly enough for anything significant. The actual effects and to track them, we must focus on the height fields. That is why the zonal mean zonal wind is also so important because is directly related to the geopotential height field via geostrophicy. 

 

Well geopotential height is directly related to temperature. The temperatures are important, but you need to look at the right ones - 10 mb temperature is a fairly poor determinant of 10 mb wind.

There are a series of papers from the 1970s by Quiroz and others which examine warmings - 'high radiance systems' or 'thermal systems' as they refer to them, using early satellite infrared sensors. They are interesting as the researchers are like detectives, piecing together an understanding of the then recently recognised SSW, using early remote sensing data, and they are relatively easy reading being largely descriptive rather than theoretical. However, though they are still occasionally cited, many good observations are now largely overlooked.

Anyway, of major/minor SSW and wind reversals they say -

Quote

It is useful to distinguish major warmings as those events in which poleward movement of planetary-scale thermal systems results in a reversal of the polar circulation at 10 mb (30 km) or below. Synoptic maps of satellite radiation data show that this condition may be met when systems of high radiance, as measured in the stratospheric channels of the satellite radiometers, move to the pole, displacing the cold air normally associated with the polar vortex.

In minor warmings, which are fairly common in both hemispheres, the trajectory of warm cells tends to retain a basically zonal (eastward) direction, and local warmings may be observed in connection with the passage of a single warm-air system or as a consequence of the superposition of two warm cells. Infrequently, the trajectory may exhibit a strong poleward component, but polar warming in the middle or lower stratosphere is insufficient to reverse the circulation except possibly at very high stratospheric or mesospheric altitudes. Significant distortion or elongation of the polar vortex may occur, however, at lower stratospheric altitudes.

[re: circulation reversals] Note the quasi-isothermal structure in the right side of Fig. 7. [shows roughly equal temperatures with height through much of the stratosphere]. The appearance of this structure in the polar region, which is indicative of warming in the lower stratosphere, is easily detected in the satellite data by the convergence to a common value of radiances measured in the different stratospheric channels. The occurence of a circulation reversal in the polar region depends on the lower stratospheric temperature at this isothermal state, which may or may not exceed the temperature at lower latitudes. It also depends on the depth of the polar vortex at the base of the stratosphere, since sufficient warming must occur not only to reverse the meridional temperature gradient within the stratosphere, but also to compensate hydrostatically for low pressure associated with the tropospheric thermal structure.

http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1975)032<1723%3AACOOAS>2.0.CO%3B2

Using the MERRA data, there is a tendancy towards an isothermal signature but it is a little hit and miss as a diagnostic, but the other key observations of having a sufficient warming in lower levels in the heart of the vortex, and having a reversed meridional temperature gradient which gives an easterly thermal wind shear are very important, which can be seen by taking the difference between the 80°N and 50°N temperatures at 50 mb.

For example, of 2246 days in January and February, there are 177 with a wind reversal @ 10 mb 60°N.

Of these, 175 or 98.9% had a temperature reversal at 50 mb, and the other two days had a temperature reversal the following day.

This compares to 119 days or 67.2% for 10 mb temperature gradient.

The 50 mb temperature reversal doesn't guarantee a SSW, with 266 false positives (11.8%), maximum windspeed 20.21 m/s, but it is pretty much a prerequisite for a 10 mb wind reversal and it is much better than the 534 false positives (23.8%), max speed 47.44 m/s from the 10 mb temperatures.

So applying this to these charts posted previously -

On 2/7/2016 at 11:30 AM, Paul123 said:

 

05/01/13 - wind reversal 06/01/13, one of 50 mb temp two misses, it reversed next day. 10 mb was false positive for 05/01 but reversal next day was correct.

08/02/14 - wind speed 19.06 m/s, 50 mb temp gradient not reversed -3.58, correct. 10 mb reversed 14.11 wrong.

08/01/15 - wind speed 19.32 m/s, 50 mb temp not reversed -11.22, correct. 10 mb reversed 1.08 wrong.

07/02/16 - wind speed 24.91 m/s, 50 mb not reversed -21.57 correct. 10 mb reversed 9.67 wrong.

 

[feb1991blizzard]

GFS 12z run, I'm going for less than 10 m/s but not quite a reversal!

[Nouska]

10 minutes ago, feb1991blizzard said:

GFS 12z run, I'm going for less than 10 m/s but not quite a reversal!

The 65N graph says yes to reversal but not sure where the usual 60N would be.    

The ECM on last frame is getting closer.   

 

[feb1991blizzard]

Just now, Nouska said:

The 65N graph says yes to reversal but not sure where the usual 60N would be.    

The ECM on last frame is getting closer.   

 

Cheers, blimey, I didn't know the ECM was that close, ive been following the hemispheric charts at 1,10 and 30mb the last few days hoping to get agreement at 240 with some of the better GFS runs, strange to have a 65N chart and not a 60N.

[Nouska]

1 hour ago, feb1991blizzard said:

Cheers, blimey, I didn't know the ECM was that close, ive been following the hemispheric charts at 1,10 and 30mb the last few days hoping to get agreement at 240 with some of the better GFS runs, strange to have a 65N chart and not a 60N.

It would be interesting if we did see a technical SSW in early March - according to the Berlin site, last occasion was 1988. There were a couple of occasions in the fifties, sixties and seventies and four in the eighties; all classed as the final warming of that winter.

A mixed bag regarding the corresponding CET figure for March - highest was  1961 with 8.2C then 1959 at 7.3C. 1988 saw 6.4C, 1954 and 1974 tied at 5.8C. The remaining five years '64, '75, '80, '84 and '86 all had a CET in the fours, ranging from 4.3C to 4.9C.

Any significance? probably not, but a bit of trivia does nobody any harm.

[chionomaniac]

2 hours ago, Nouska said:

The 65N graph says yes to reversal but not sure where the usual 60N would be.    

The ECM on last frame is getting closer.   

 

Hi Nouska - I think that the Hannah Attard chart is from the GFS 00Z run - still not bad to acheive a reversal from that forecast displacement. Looks like a reversal at 60ºN as well - but only just, and not the vortex destruction wanted shown just yet.

[Interitus]

36 minutes ago, Nouska said:

It would be interesting if we did see a technical SSW in early March - according to the Berlin site, last occasion was 1988. There were a couple of occasions in the fifties, sixties and seventies and four in the eighties; all classed as the final warming of that winter.

A mixed bag regarding the corresponding CET figure for March - highest was  1961 with 8.2C then 1959 at 7.3C. 1988 saw 6.4C, 1954 and 1974 tied at 5.8C. The remaining five years '64, '75, '80, '84 and '86 all had a CET in the fours, ranging from 4.3C to 4.9C.

Any significance? probably not, but a bit of trivia does nobody any harm.

10 mb 60°N reversals from MERRA data -

22/03/92 FW

29/03/98 FW

20/03/00

12/03/05 FW

24/03/10

27/03/14 FW

28/03/15 FW

Berlin uses different criteria for SSW and uncertain when their list will be updated as Karin Labitzke passed away last year sadly.

[TomDav]

1 hour ago, chionomaniac said:

Hi Nouska - I think that the Hannah Attard chart is from the GFS 00Z run - still not bad to acheive a reversal from that forecast displacement. Looks like a reversal at 60ºN as well - but only just, and not the vortex destruction wanted shown just yet.

Yep GFS 12z was a reversal of -2.2 m/s @ 384hrs (60N)

[Nouska]

1 hour ago, Interitus said:

10 mb 60°N reversals from MERRA data -

Many thanks for the info - I was puzzled by lack of marked SSWs in March, after '88.

Sad news about Karin Labitzke.

[Yarmy]

16 hours ago, Interitus said:

10 mb 60°N reversals from MERRA data -

22/03/92 FW

29/03/98 FW

20/03/00

12/03/05 FW

24/03/10

27/03/14 FW

28/03/15 FW

Berlin uses different criteria for SSW and uncertain when their list will be updated as Karin Labitzke passed away last year sadly.

There's an obituary for Prof. Labitzke here:

http://www.geo.fu-berlin.de/en/met/sharp/news/Obituary_Karin_Labitzke.pdf

"A milestone of stratospheric dynamical research was Karin Labitzke’s finding of a relation between the occurrence of stratospheric warmings, the QBO at the equator and the phase of the 11-year solar cycle. She published her discovery for the first time in 1987, together with her colleague and close friend Harry van Loon from NCAR. While they were initially criticized by a number of colleagues, this relationship has since been convincingly proven to be robust and is nowadays established."  

Her book is here:

http://www.springer.com/gb/book/9783642636370

 

 

[feb1991blizzard]

The 1mb chart on the 18z GFS has just about as -ve a zonal wind as you can get!!!!

[Nouska]

The Combined Influences of Westerly Phase of the Quasi-Biennial Oscillation and 11-year Solar Maximum Conditions on the Northern Hemisphere Extratropical Winter Circulation

https://www.jstage.jst.go.jp/article/jmsj/93/6/93_2015-054/_pdf

 

Quote

The combined influences of the westerly phase of the quasi-biennial oscillation (QBO-W) and solar maximum (Smax) conditions on the Northern Hemisphere extratropical winter circulation are investigated using reanalysis data and Center for Climate System Research/National Institute for Environmental Studies chemistry climate model (CCM) simulations. The composite analysis for the reanalysis data indicates strengthened polar vortex in December followed by weakened polar vortex in February-March for QBO-W during Smax (QBO-W/Smax) conditions. This relationship need not be specific to QBO-W/Smax conditions but may just require strengthened vortex in December, which is more likely under QBO-W/Smax. Both the reanalysis data and CCM simulations suggest that dynamical processes of planetary wave propagation and meridional circulation related to QBO-W around polar vortex in December are similar in character to those related to Smax; furthermore, both processes may work in concert to maintain stronger vortex during QBO-W/Smax. In the reanalysis data, the strengthened polar vortex in December is associated with the development of north-south dipole tropospheric anomaly in the Atlantic sector similar to the North Atlantic oscillation (NAO) during December-January. The structure of the north-south dipole anomaly has zonal wavenumber 1 (WN1) component, where the longitude of anomalous ridge overlaps with that of climatological ridge in the North Atlantic in January. This implies amplification of the WN1 wave and results in the enhancement of the upward WN1 propagation from troposphere into stratosphere in January, leading to the weakened polar vortex in February-March. Although WN2 waves do not play a direct role in forcing the stratospheric vortex evolution, their tropospheric response to QBO-W/Smax conditions appears to be related to the maintenance of the NAO-like anomaly in the high-latitude troposphere in January. These results may provide a possible explanation for the mechanisms underlying the seasonal evolution of wintertime polar vortex anomalies during QBO-W/Smax conditions and the role of troposphere in this evolution.

 

 

[knocker]

 

[feb1991blizzard]

I've thought for a while now that this warming was going to be the end of the PV for the season, its just the nuances and how it affects the troposphere that's up for grabs now I think, just wondering what the experts think will happen wrt any tropospheric blocking patterns and if the lack of posts is due to a lack of any confidence in the model output or whether its just apathy due to the lateness of the SSW or whether we are just playing a game of wait and see?

[Cloud 10]

Reverse zonal winds at 60N 10mb at day 10 from the ECM.

 

 

 

[knocker]

 

[Singularity]

    

A neat sequence here;

+96 shows the stratospheric ridge over the U.S. that is the product of the Jan-Feb warming events, and the effect on the vortex - an elongation and gradual displacement toward Eurasia - but with the new warming event entering the stage in a similar location to the one in late Jan.

+192 shows how this new event is able to deliver a lethal punch, tearing away a classic 'comma' of low heights from the vortex, as opposed to just shoving it back toward the U.S. such as the late Jan event did... much to our displeasure.

+276 illustrates the favourable positioning of the stratospheric ridge on this occasion for tropospheric blocking N and NW of the UK - which is the best so far from today's 12z GFS.

+384 shows the longevity of the event. Currently no further activity is showing up to shake things up again. Its seems unlikely to me that the vortex would recover from there - making this the 'final warming' event of winter 2015/16.

I expect westerlies will be a rare commodity throughout March and perhaps well into April. That doesn't necessarily mean cold the whole way though; once the MJO leaves phase 8/1 in a few weeks time, it's conceivable that we could see the blocking features arrange in favour of a warmer pattern. Or they could remain in a cold setup... who knows. I gather GloSea5 is hinting an an April a bit like 2010 (mid-Atlantic high displaced N. from the Azores) but without the Icelandic ash cloud I expect!

[Interitus]

NASA GEOS model now has first forecast for 10mb 60N wind reversal on 5th March -0.57 ms

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/u60n_10_2015_merra.pdf

[Cloud 10]

Certainly full steam ahead from yesterday's ECM.

 

-60m/s higher up in the strat and downwelling by the look of it.

 

[Duane S.]

14 hours ago, Cloud 10 said:

Certainly full steam ahead from yesterday's ECM.

 

-60m/s higher up in the strat and downwelling by the look of it.

 

I'm surprised this zonal wind chart has not had any more comments made ref. it. Maybe because we are about to enter March and model weariness has taken its toll, but that is a truly staggering chart! The reprocussions should it ( or something similar) verify will be very interesting indeed to observe.

[mountain shadow]

1 hour ago, s4lancia said:

I'm surprised this zonal wind chart has not had any more comments made ref. it. Maybe because we are about to enter March and model weariness has taken its toll, but that is a truly staggering chart! The reprocussions should it ( or something similar) verify will be very interesting indeed to observe.

I think its because even if it were to lead to copious blocking to the NE or NW there is no deep cold to tap into.

 

[Interitus]

Added to the above, lack of comment could be because it will be the start of spring and there may not be high expectation of anything, but also I don't think anyone knows what will happen TBH. It's a question to how this will propagate to the lower levels through the various effects of hydrostatic adjustment, vorticity inversion and vertical wind shear. There is a good chance that 10mb 60N winds will return to a weak westerly for a short while but won't re-strengthen now to any degree and subsequent weak reversals may actually prove more significant, though of course increasingly late in season.

it's interesting in its own right though and the ECM forecast 10mb 60N wind from yesterday of -19 m/s would be the strongest March reversal in the MERRA data if verified. It is at day 10 of course and for example the GEOS forecasts out to 8 days have shown a lot of scatter after about day 6, but interestingly the last couple of runs firmed up as soon as the reversal was in sight, with -9.72 m/s by the 6th at this point even stronger than the ECM -4.2 m/s (not sure exactly same forecast time) -

The action at 10mb level has been quite extreme this season, with the second strongest winds followed by warming breaking some daily records leading to second most rapid weakening of wind speed in January. Of course the wave activity at lower levels was insufficient to force a full SSW at that time. Now once again this forecast SSW seems to be happening a few days earlier than expected, for example from looking at the closest rms difference 30-day vortex 80°N-50°N meridional temperature gradient to 06/03/16 forecast (taken from whole winter period - all six were followed by SSW) -

One other notable thing has been the anomalously low wave 2 activity. The wave 1 has been active and corresponding to the wind speed chart above shows a degree of similarity preceding SSW as might be expected -

But this year has had a lack of wave 2 even compared to these predominantly wave 1 events -

Basically it has flat-lined the whole season and been far lower than one would expect for the wind speeds experienced being more akin to the start or end of season - the analogue winds for the 4 closest last 30 day low wave 2 at this time of year shows that none really approached this year's strength and 3 of the 4 had already had an SSW - this may be something worthy of investigation regarding troposphere influence -

I'll have a look at impacts of March SSW but here are some reversal dates from MERRA to start with for anyone interested - 17/03/80, 04/03/81, 01/03/84, 24/03/85, 19/03/86, 14/03/88, 07/03/89 (strictly speaking continuation of 21/02/89), 22/03/92, 29/03/98, 20/03/00, 12/03/05, 13/03/08, 24/03/10, 27/03/14, 28/03/15

 

 

Edited February 28, 2016 by Interitus

[Recretos]

I made a new animation from the GFS 3D data, showing the actual vortex breakup. it will look better once the breakup period gets within 240h where the temporal resolution is much better.