Stratosphere Temperature Watch 2015/2016

[KyleHenry]

10 hours ago, bryan629 said:

This is Cohens latest blog..... 

http://www.aer.com/science-research/climate-weather/arctic-oscillation

What i would like to know is this paragraph good news or bad news for the uk 

30–day

I remain confident that a T-S-T coupling event is ongoing and about to enter its final stage.   The strong negative AO state that dominated January (Figure 1) was a tropospheric precursor that initiated a strong burst of vertical energy transfer (and is predicted to be record breaking) from the troposphere into the stratosphere that will peak over the next few days as seen in the vertical wave activity flux (WAFz) plot (Figure 8). Model runs continue to predict that this energy burst will result in record warm temperatures for the polar stratosphere and force an impressive SSW.  As we discussed above, this will result in an almost immediate tropospheric response resulting in Arctic outbreaks for East Asia and especially the Eastern United States.

For the UK it's a no. We are currently and will be in the cool mix but only at the outer edges of what Dr Cohen speaks of.That will be for the next 7 days then the PV reforms. 

There is a reversal at the 10hPa level, but it only persists for approximately 48 hours as shown by charts below. 

Yes to a -AO, yes to record temperatures and yes to the tropospheric response. The fact remains that it is very short lived. 

From my point of view it is a SSW, but only the briefest of SSW. 

 

 

[KyleHenry]

12 hours ago, feb1991blizzard said:

It might do although maybe unlikely, if the mean zonal wind speed at 60N up at 10mb never recovers to above zero for the rest of the stratospheric season, then it would by definition be a final warming.

That is a possibility. This next forecasted MT event is still not confirmed but what has me interested is if it verifies and following Tropospheric response we could find our long lost -NAO,only Spring/Summer as usual.

[feb1991blizzard]

9 hours ago, KyleHenry said:

That is a possibility. This next forecasted MT event is still not confirmed but what has me interested is if it verifies and following Tropospheric response we could find our long lost -NAO,only Spring/Summer as usual.

 

Not sure if this has anything to do with another strong warming starting right up top on the 12z GFS. A -NAO is not out of the question for mid March.

[damianslaw]

10 hours ago, KyleHenry said:

That is a possibility. This next forecasted MT event is still not confirmed but what has me interested is if it verifies and following Tropospheric response we could find our long lost -NAO,only Spring/Summer as usual.

Yes we've seen negative NAO periods in many recent summers, significant and long lasting ones as well. Would not be surprised at all if we see a change to a negative NAO during March, and lasting a while, as there has been a propensity for negative and positive NAO states to be lengthy in duration over recent years..

The Cohen Blog suggests an increased chance of colder conditions back end of winter and into Spring, but yes there is uncertainty. I wouldn't dismiss the chances of the strat warming playing out favourably for a colder pattern as we enter spring.

Edited February 9, 2016 by damianslaw

[Singularity]

Based on these indications for another significant warming late in the month I am getting a nasty feeling that (at least) the first half of 2016 will be remembered as exceedingly unkind to the Arctic sea ice - though I need to check over in the scientific forum whether a negative NAO tends to be bad for the ice extent during the spring. It certainly seems to be so in the summer (2007 and 2012. Need I say more).

 

Anyway, in the UK, I sense that spring may have trouble getting going this year but as yet don't have strong enough signals to expect lying snow either. So I have rather a neutral mood at this point in time!

 

 

[feb1991blizzard]

Very significant displacement warming causing reversal at 1mb and its started to propagate on the 18z.

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2016020918&var=HGT&lev=1mb&hour=384

 

[Interitus]

On 2/8/2016 at 4:03 PM, KyleHenry said:

Second forecasted +MT event in outer range of GFS, will be a swift end to the vortex.

Thought I cleared up this (EA)MT nonsense?

[Cloud 10]

Which ever way you look at it that's a mighty impressive warming over the pole,with a 60C jump in a very short space of time.

 

from..to..

[KyleHenry]

6 hours ago, Interitus said:

Thought I cleared up this (EA)MT nonsense?

MT nonsense? 

East Pacific LP system and Siberian HP. 

It may not evolve as shown in chart below but when NEPAC LP moves position it allows Siberian HP mass to move Eastwards over Kamchatka/ East Russian Highlands creating a + MT event on the down slope. 

 

 

Edited February 10, 2016 by KyleHenry

[knocker]

 

 

[feb1991blizzard]

29 minutes ago, knocker said:

 

 

The next warming is only in the far reaches of FI up top yet, so we have to see what that brings, re- the vortex - the bigger they are, the harder they fall.

[Interitus]

On 2/10/2016 at 2:05 PM, KyleHenry said:

MT nonsense? 

East Pacific LP system and Siberian HP. 

It may not evolve as shown in chart below but when NEPAC LP moves position it allows Siberian HP mass to move Eastwards over Kamchatka/ East Russian Highlands creating a + MT event on the down slope. 

So the +MT is this down slope flow over Kamchatka/East Russian Highlands causing an adiabatic compressional warming which can be seen in the image below? -

On 2/8/2016 at 4:03 PM, KyleHenry said:

 

OK, assuming that it is possible, firstly mountain waves are static waves, essentially occurring fixed above the mountains but it is over 3000 km from Kamchatka to the centre of the warming near Khatanga and the Taymyr area, and it is also in the upwind direction which doesn't make sense for a down slope wind.

Second, where is the air descending from? There has to be uplift to compensate which should be the mountain up slopes, but this would cause cooling and the only area of this is even further away over the north Atlantic.

Thirdly, the waves rely on a stable atmosphere otherwise it would trigger convection and there would be no warm descending wind. The stratosphere pretty much guarantees stability being isothermal in the lower layers and warming with height towards the stratopause, but then the effect of this is that the air parcels oscillate up and down at the Brunt-Vaisala frequency until they return to equilibrium. In other words, wind hits the mountains, the air is forced up away from its stable position so then sinks back down but overshoots below the original height and becomes buoyant and rises again. This repeats a handful of times with the overshooting above and below the stable position becoming less until it settles at the equilibrium height and temperature once more. The rising air motion causes cooling and the sinking air warming, which creates a characteristic rippled temperature pattern, not a single warm swathe.

Fourthly, it might be inferred that the warming is in some way similar to the Fohn effect, but this involves diabatic temperature changes through condensation and precipitation so that the sinking air warms at a greater rate than the rising air cools, thus giving a net temperature gain from latent heat release after passing the mountains. Of course there is not enough water vapour for clouds and precipitation in the stratosphere, and temperature changes are largely adiabatic in the short term. So air rising and descending cools and warms at the same rate and the overall average stays the same.

Fifthly, counter to point 4 above, the waves can cause an amount of lasting warming by mixing air parcels when the waves break. This helps make the upper polar stratosphere generally warmer from mid-winter onwards, when waves break towards the stratopause. This is however usually above the 10 mb level, and the waves are propagated up the edge of the vortex which at its nearest point is unsurprisingly getting on towards 3000 km away like the warming -

 In any case, east Siberia and Kamchatka are under easterly winds from the Aleutian high, there will be a critical layer where mountain waves will not be able to propagate - they will dissipate and not reach the 10 mb level.

Returning to the baroclinic forcing explanation, once again the crossed geopotential contours show a rough depiction of temperature/thickness advection and rising and sinking motions caused by geostrophic shear advection -

 

I'm afraid that the baroclinic forcing has been the accepted explanation for decades, which is why the Berlin uni stratosphere site shows wave heights and temperature amplitudes etc. They don't show EAMT, and it doesn't feature in the literature at all with regards to warmings such as this, it only crops up in forums, blogs and social media.

 

[KyleHenry]

5 hours ago, Interitus said:

So the +MT is this down slope flow over Kamchatka/East Russian Highlands causing an adiabatic compressional warming which can be seen in the image below? -

OK, assuming that it is possible, firstly mountain waves are static waves, essentially occurring fixed above the mountains but it is over 3000 km from Kamchatka to the centre of the warming near Khatanga and the Taymyr area, and it is also in the upwind direction which doesn't make sense for a down slope wind.

Second, where is the air descending from? There has to be uplift to compensate which should be the mountain up slopes, but this would cause cooling and the only area of this is even further away over the north Atlantic.

Thirdly, the waves rely on a stable atmosphere otherwise it would trigger convection and there would be no warm descending wind. The stratosphere pretty much guarantees stability being isothermal in the lower layers and warming with height towards the stratopause, but then the effect of this is that the air parcels oscillate up and down at the Brunt-Vaisala frequency until they return to equilibrium. In other words, wind hits the mountains, the air is forced up away from its stable position so then sinks back down but overshoots below the original height and becomes buoyant and rises again. This repeats a handful of times with the overshooting above and below the stable position becoming less until it settles at the equilibrium height and temperature once more. The rising air motion causes cooling and the sinking air warming, which creates a characteristic rippled temperature pattern, not a single warm swathe.

Fourthly, it might be inferred that the warming is in some way similar to the Fohn effect, but this involves diabatic temperature changes through condensation and precipitation so that the sinking air warms at a greater rate than the rising air cools, thus giving a net temperature gain from latent heat release after passing the mountains. Of course there is not enough water vapour for clouds and precipitation in the stratosphere, and temperature changes are largely adiabatic in the short term. So air rising and descending cools and warms at the same rate and the overall average stays the same.

Fifthly, counter to point 4 above, the waves can cause an amount of lasting warming by mixing air parcels when the waves break. This helps make the upper polar stratosphere generally warmer from mid-winter onwards, when waves break towards the stratopause. This is however usually above the 10 mb level, and the waves are propagated up the edge of the vortex which at its nearest point is unsurprisingly getting on towards 3000 km away like the warming -

 In any case, east Siberia and Kamchatka are under easterly winds from the Aleutian high, there will be a critical layer where mountain waves will not be able to propagate - they will dissipate and not reach the 10 mb level.

Returning to the baroclinic forcing explanation, once again the crossed geopotential contours show a rough depiction of temperature/thickness advection and rising and sinking motions caused by geostrophic shear advection -

 

I'm afraid that the baroclinic forcing has been the accepted explanation for decades, which is why the Berlin uni stratosphere site shows wave heights and temperature amplitudes etc. They don't show EAMT, and it doesn't feature in the literature at all with regards to warmings such as this, it only crops up in forums, blogs and social media.

 

A fair point, to my simplistic post. 

Here is my thoughts from source to completion when I have referred to MT event. 

Winter 2015/16's key factor has been ongoing El Niño. Yes many other factors WQBO, low solar flux, strong PV etc.

+PDO in an El Niño year.Huge oceanic kelvin waves downwelling creating wave trains of moisture and kinetic energy Westwards along the equator towards ENSO region 4.

Rossby wave bands emit from IO when MJO is in phases 2/3/4 from Autumn through WinterWHen the build up of energy is sufficient, it will break out in more numerous waves. 

They must ajoin with wave 1 at crucial timing which is what we saw with brief SSW at the beginning of this month.

I view the Aleutian Low and its moving of position as key in allowing the Eastward movement of Siberian High. 

This eastward movement in my opinion acts as a stepping stone for the kinetic energy to achieve interaction with lower Stratosphere. 

With the PV situated over Greenland, it proves the most logical entry point for that energy to enter. Due to the strength of this seasons PV, O3 ozone was prevented until beginning of Feruary to assist in process. Now look at current Rossby wave dynamics ongoing courtesy of Michael Ventrice at WSI. It allows greater opportunity for kinetic energy to get to 1 hPa level and allow downwelling. 

Not only that the effects of brief SSW, is now pushing Tropospheric air down towards Eastern U.S. 

This tilts PV and could allow another SSW or impressive final warming event. It will require Siberian High pressure to move eastwards and it will require alignment of ongoing waves to propagate next possible SSW. 

It is my hypothetical theory and is open to discussion, bear in mind I am an amateur enthusiast. I hope this is a clearer description of what I mean by + MT/ EAMT event.

[lorenzo]

Some interesting scientific argument around on this Mountain Waves and Mountain Torques debate - I think they remain two separate strands. EAMTs are a lift feature for AAM and a steroidal injection to the overall AAM budget via the torque process.

On occurrence this perturbs the vortex -  I would not say the EAMT is #rubbish.

As ever I openly admit that my understanding of the processes is not as scientific or as experienced as others, however I think there the two tangents here that are creating disconnect  - the Siberian High anomaly and Pacific Low conduit operate, and have been cited in more than one paper, as Stratospheric starter pistols via the EAMT to create pressure on the vortex.

Am not questioning the scientific analysis, that is fully appreciated, always good to be learning more. I just see no value in discrediting torque events. Apples and pears?

 

 

[feb1991blizzard]

The vortex at the top is looking like leading a really charmed life in Early March, a strong warming pushing it from pillar to post on the 18z (the best temp profile at 1mb seen over the pole this winter),  it still cant get right into the heart of it though to rip it apart, hopefully wont be long now and will give us a chance of blocking by mid March.

[kumquat]

On 07/02/2016 at 7:13 AM, Paul123 said:

Measuring (determining) a warming in (by) meter per second is asking for trouble. Sooner or later someone will come up with a more plausible alternative, resulting in even more confusion.

To use one line in space also is far from elegant, when defining a warming for the whole of the polar stratosphere. 

Everwhere on forums, and when talking to people, I notice incomprehension concerning the used method of classification.

This definition should be adjusted sooner or later, I think.

It's distance over time in a given vector (aka velocity). How else could you measure a warming of layers of air in any meaningful way?

You'll need to invoke the calculus if you want to take things further. Good luck simplifying that "when talking to people".

Edited February 14, 2016 by kumquat

[knocker]

I don't know whether this is of interest here

Unusual cold spell in the stratosphere creates conditions for severe ozone depletion in the Arctic

Quote

[10. February 2016] 

Unusual weather development in the Arctic leads to ozone depletion. According to the researchers of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, in the past weeks an extreme cold spell in the Arctic stratosphere has created conditions that might cause severe ozone depletion over the Arctic in March – if the next few weeks will not bring a significant warming.

 

http://www.awi.de/nc/en/about-us/service/press/press-release/ungewoehnliche-kaelteperiode-in-der-stratosphaere-schafft-bedingungen-fuer-starken-ozonabbau-in-der.html

Article

http://www.sciencemag.org/news/2016/02/record-ozone-hole-may-open-over-arctic-spring

 

[Interitus]

On 2/12/2016 at 9:01 PM, lorenzo said:

Some interesting scientific argument around on this Mountain Waves and Mountain Torques debate - I think they remain two separate strands. EAMTs are a lift feature for AAM and a steroidal injection to the overall AAM budget via the torque process.

On occurrence this perturbs the vortex -  I would not say the EAMT is #rubbish.

As ever I openly admit that my understanding of the processes is not as scientific or as experienced as others, however I think there the two tangents here that are creating disconnect  - the Siberian High anomaly and Pacific Low conduit operate, and have been cited in more than one paper, as Stratospheric starter pistols via the EAMT to create pressure on the vortex.

Am not questioning the scientific analysis, that is fully appreciated, always good to be learning more. I just see no value in discrediting torque events. Apples and pears?

 

 

 

At no point have torque events been discredited, the contention was that an chart of classic wave 1 warming ≠ MT

Indeed, I previously mentioned the role of Coriolis and lee cyclogenesis which is at the heart of mountain torque. But then this is back solidly into Rossby/planetary wave territory which may perturb the vortex, not the torque directly.

 

[Nouska]

On ‎2‎/‎3‎/‎2016 at 0:36 PM, sebastiaan1973 said:

 

http://onlinelibrary.wiley.com/doi/10.1002/2013JD021343/abstract

This research is being well reflected in the current solar activity graphs. Although SSN continues to decline the geomagnetic activity of this cycle reached a peak during 2015 - the highest it has been since 2005. How much has this influenced the strength of the stratospheric vortex and reinforced the positive NAO signal?

SSN    Ap     

Quote from abstract ....

Using 13 solar cycles (1869–2009), we study winter surface temperatures and North Atlantic oscillation (NAO) during four different phases of the sunspot cycle: minimum, ascending, maximum, and declining phase. We find significant differences in the temperature patterns between the four cycle phases, which indicates a solar cycle modulation of winter surface temperatures. However, the clearest pattern of the temperature anomalies is not found during sunspot maximum or minimum, but during the declining phase, when the temperature pattern closely resembles the pattern found during positive NAO. Moreover, we find the same pattern during the low sunspot activity cycles of 100 years ago, suggesting that the pattern is largely independent of the overall level of solar activity.

 

[sebastiaan1973]

Hi Nouska, what's opinion. Is the winter of 2017 still in the 'declining phase'?

[chionomaniac]

I reckon that we have another year of the declining phase before we can say that we are in the minimum phase.  And when we are just exiting the minimum on the upward slope looks like a good time for the negative NAO. Will factor this in to the next few winter forecasts. The winter we probably want is with ascending solar just exiting min, eQBO, moderate Modiki EN, -ve AMO and so on.

[Yarmy]

9 minutes ago, chionomaniac said:

I reckon that we have another year of the declining phase before we can say that we are in the minimum phase.  And when we are just exiting the minimum on the upward slope looks like a good time for the negative NAO. Will factor this in to the next few winter forecasts. The winter we probably want is with ascending solar just exiting min, eQBO, moderate Modiki EN, -ve AMO and so on.

 

Mid-2017 before the mean solar flux drops below 80 looking at the predicted values. Last minimum was as we know quite protracted (sub-80 sfu mean between mid-2006 to mid-2010) and there's some evidence that might be the case again so perhaps 2020 or beyond before it bottoms out?

eQBO seems likely for next winter, not that it helped much last winter.

[feb1991blizzard]

The vortex completely destroyed at 1mb, if that could propagate then that could be a very early end to the vortex.

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2016021612&var=HGT&lev=1mb&hour=384

Not far off a technical SSW now.

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2016021612&var=HGT&lev=10mb&hour=384

[snowking]

2 hours ago, chionomaniac said:

I reckon that we have another year of the declining phase before we can say that we are in the minimum phase.  And when we are just exiting the minimum on the upward slope looks like a good time for the negative NAO. Will factor this in to the next few winter forecasts. The winter we probably want is with ascending solar just exiting min, eQBO, moderate Modiki EN, -ve AMO and so on.

I cannot for the life of me find the paper now but I remember reading on a break from work quite a few years ago now a paper by two Japanese scientists on the predictability of grand solar minima based upon cycle length in the directly preceding years. Their observations at the time were that directly preceding the Dalton and Maunder Minimums (n.b. - this is NOT me predicting any such minimum upcoming!) the ~11 year cycles elongated year on year and unexpectedly. Their observations at the time were that the end of Cycle 23 exhibited exactly such behaviour and that the biggest sign of an impending longer solar decline was successive elongated cycled - 23 certainly exhibited this and from the looks of where we have already been/are headed we look to be on course to further elongate the overall cycle length in 24.

The end of this decade is going to be fascinating, if excruciating to wait for

SK

[KyleHenry]

It is only one run so I'm taking dynamics with intrepid caution.

GFS showing wave 1 having different effect on PV. It portrays predicted SSW mark 2 to gain access to 1hPa in Eurasian zone rather than East Asia. 

This if true changes everything for us in Europe by 5th March 2016. More to watch maybe prolonged cold spell with -NAO.

MJO into sector/ high orbit 8 as shown.