Stratosphere Temperature Watch

[chionomaniac]

Having compared the forecast for the next few days to last winter, I am convinced that the strength of the forecast stratospheric warming event is very significant. If we were in the middle of the stratospheric winter, I am sure that we could be looking at a possible SSW. However we are not, and therefore we are likely to see a sharp exit from the stratospheric winter in the form of a dramatic final warming. I cannot help but feel that the sudden reversal of zonal winds forecast will have some kind of effect on the troposphere, and still believe that the current tropospheric pattern will be shifted somewhat by dramatic stratospheric changes. Furthermore I also believe that the stronger any change in the stratosphere, the quicker the effect is felt in the troposphere. So, I expect to see a rather rapid turnaround in the strength of the polar vortex around the middle of the month with more emphasis on polar height rises than we have seen all year. Whether this occurs in an area that will shift our pattern of mid latitude height rises remains to be seen, but I would expect to see some changes with cooler conditions ensuing before the underlying low angular momentum state reasserts itself as May progresses.

c

[knocker]

Given the very cold stratosphere this winter this is not that surprising but worthwhile keeping an eye on UV values in the mid latitudes.

Recent observations from satellites and ground stations suggest that atmospheric ozone levels for March in the Arctic were approaching the lowest levels in the modern instrumental era. What those readings mean for the remainder of the year is unclear. But what they mean for the long-term is that the recovery from human-induced ozone depletion is an uneven climb.

These maps of ozone concentrations over the Arctic come from the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite. The left image shows March 19, 2010, and the right shows the same date in 2011. March 2010 had relatively high ozone, while March 2011 has low levels. The large animation file (linked below the images) shows the dynamics of the ozone layer from January 1 to March 23 in both years.

In mid-March, scientists from Germany’s Alfred Wegener Institute announced that Arctic ozone levels had been cut in half in the waning weeks of winter, according to a network of 30 ozone sounding stations spread around the region. Data from OMI (shown above) also confirmed a depletion. OMI is a spectrometer that measures the amount of sunlight scattered by Earth’s atmosphere and surface, allowing scientists to assess how much ozone is present at various altitudes, particularly the stratosphere.

Ozone is destroyed when chlorine- or bromine-based compounds—especially chlorofluorocarbons (CFCs) —break into their free atoms and combine with the oxygen. That process is amplified when the stratosphere is especially cold, which it has been in recent weeks.

“This depletion is not necessarily a big surprise,†said Paul Newman, an atmospheric scientist and ozone expert at NASA's Goddard Space Flight Center. “The ozone layer remains vulnerable to large depletions because total stratospheric chlorine levels are still high, in spite of the regulation of ozone-depleting substances by the Montreal Protocol. Chlorine levels are declining slowly because ozone-depleting substances have extremely long lifetimes.â€

The concentration of ozone in the Arctic atmosphere varies greatly from year-to-year, and ozone “holes†do not form consistently like they do in Antarctica. “Last winter, we had very high lower stratospheric temperatures and ozone levels were very high; this year is just the opposite,†Newman said. “The real question is: Why is this year so dynamically quiet and cold in the stratosphere? That’s a big question with no good answer.â€

Scientists will be watching in coming months for possible increases in the intensity of ultraviolet radiation (UV) in the Arctic and mid-latitudes, since ozone is Earth’s natural sunscreen. “We need to wait and see if this will actually happen,†Newman said. “It’s something to look at but it is not catastrophic.â€

On a global scale, the ozone layer is still on a long-term course for recovery. But for decades to come, there remains a risk of major ozone losses on yearly or regional scales.

Courtesy NASA’s Earth Observatory

NASA image by Rob Simmon, with data courtesy of Ozone Hole Watch. Caption by Mike Carlowicz and Kristyn Ecochard.

[chionomaniac]

That is quite a dramatic difference ws

[MR EXTREMES]

That is quite a dramatic difference ws

although my thoughts are if a strat warming event happens could well go in favour of mid lat blocking!

there for possibility of or if and when eastern europe heats up shiftingg very warm air to our parts also blocking becoming more favourate over the uk!

like in winter we get homegrown heat so not a bad thing with a bbq summer possible

[chionomaniac]

The latest ECM outlook suggests a very mean zonal negative wind heading right down towards the troposphere. Mean negative zonal winds are forecast to be -20m/s at the 10 hPA level!!

With the vortex being very much displaced towards the Siberian land mass the opportunity for a northerly is very much increased. And with the MJO forecasts aligning well I am becoming more convinced that a change is on the way.

http://www.cpc.ncep.noaa.gov/products/people/wd52qz/mjoindex/index/diagram_40days_forecast_GEFS_membera.gif

c

[MR EXTREMES]

The latest ECM outlook suggests a very mean zonal negative wind heading right down towards the troposphere. Mean negative zonal winds are forecast to be -20m/s at the 10 hPA level!!

With the vortex being very much displaced towards the Siberian land mass the opportunity for a northerly is very much increased. And with the MJO forecasts aligning well I am becoming more convinced that a change is on the way.

http://www.cpc.ncep....EFS_membera.gif

c

thanks for your info first real warming event for sometime could this be coupled with a weakening la nina?

be intresting to see what does happen and i would not rule out if this northley happens it could well be a pretty cold one as models are suggesting some very cold air around them parts.

[chionomaniac]

Normally at the end of the stratospheric winter, we see the polar vortex gradually lose strength until the westerly mean zonal winds are gradually replaced by weak easterly mean zonal winds. By definition (Polvani et al 2007) a SSW will not be considered to have occurred unless there is another spell of mean zonal westerly winds for a period of at least 10 days following the easterly mean zonal winds. If this does not occur then the warming will be classified as a final warming.

It would appear that the warming forecast in the stratosphere is likely to be a final warming as it is extremely unlikely that there will be a period of westerly winds following the sharp reversal of mean zonal winds forecast. In fact this warming has all the hallmarks of a dramatic SSW - it is just that the timing is out. In fact I would go as far to suggest that this could have a new name of its own - a Sudden Stratospheric Final Warming! I feel that there should be a distinction between what is forecast and what normally occurs.

The latest forecast suggets a far greater reversal of mean zonal winds than would normally be seen at the end of the srtratospheric winter.

All in all this does make me believe that there will be pronounced tropospheric effects as the vortex gets completely displaced to the Eurasion land mass.

As ever it is the placement of the residual energies left after such a displacement that will influence what we observe in our neck of the woods.

c

[summer blizzard]

Normally at the end of the stratospheric winter, we see the polar vortex gradually lose strength until the westerly mean zonal winds are gradually replaced by weak easterly mean zonal winds. By definition (Polvani et al 2007) a SSW will not be considered to have occurred unless there is another spell of mean zonal westerly winds for a period of at least 10 days following the easterly mean zonal winds. If this does not occur then the warming will be classified as a final warming.

It would appear that the warming forecast in the stratosphere is likely to be a final warming as it is extremely unlikely that there will be a period of westerly winds following the sharp reversal of mean zonal winds forecast. In fact this warming has all the hallmarks of a dramatic SSW - it is just that the timing is out. In fact I would go as far to suggest that this could have a new name of its own - a Sudden Stratospheric Final Warming! I feel that there should be a distinction between what is forecast and what normally occurs.

The latest forecast suggets a far greater reversal of mean zonal winds than would normally be seen at the end of the srtratospheric winter.

All in all this does make me believe that there will be pronounced tropospheric effects as the vortex gets completely displaced to the Eurasion land mass.

As ever it is the placement of the residual energies left after such a displacement that will influence what we observe in our neck of the woods.

c

Given the greater effect of this final warming, perhaps there is a correlation between a later final warming giving a bigger bounce (using the analogy of an elastic band).

[chionomaniac]

Given the greater effect of this final warming, perhaps there is a correlation between a later final warming giving a bigger bounce (using the analogy of an elastic band).

I would say not usually. 1982 is the most similar analog year to what is forecast this April.

[picog]

Temperature has finally made it above 'normal' at the 30HPa level for the second time this year! Is this the actual breaking up of the vortex?

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

[cooling climate]

Impressive warming at 30mb

[damianslaw]

Impressive warming at 30mb

I've read about the time lag involved with strat warming i.e. 20 days on average. With this in mind it looks like the effects of the current warmign won't be felt until late in the month. Do you think this warmign will finally help to trigger a weakening of the polar vortex. The vortex has been remarkable in its persistance, it should have long ago weakened, but it hasn't - surely only a matter of time that it weakens now?

[damianslaw]

Any strat temp updates - its been a while. Last forecast was major warming and with time lag we would see the effects by the end of this month - so a cooling trend on the cards maybe.. hints of northern blocking being shown in ECM and UKMO by the end of the month in line with strat warming development and weakened polar vortex. Opinions please.......

[Weather-history]

What happens during the summer, say if its unusually cold or unusually warm at that level?

[summer blizzard]

What happens during the summer, say if its unusually cold or unusually warm at that level?

Essentially the same as during winter although with the Jet Stream further north. In that regard, persistant warmth in the stratosphere is very conserning for summer in the UK.

Also exceptionally strange given that the statosphere will begin to cool again during July.

May be bad for summer ice melt although a potential thermal gradiant may heighten the hurricane season.

[Weather-history]

Essentially the same as during winter although with the Jet Stream further north. In that regard, persistant warmth in the stratosphere is very conserning for summer in the UK.

Also exceptionally strange given that the statosphere will begin to cool again during July.

May be bad for summer ice melt although a potential thermal gradiant may heighten the hurricane season.

Since very early April, the 30hpa level above the North Pole has been above average, temperature wise more or less.

[picog]

Since very early April, the 30hpa level above the North Pole has been above average, temperature wise more or less.

Temperature at 30Hpa has been on target for the past week or so.

[picog]

Strat temperatures remain at average for the time of year, and following the curve nicely.

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

[chionomaniac]

Strat temperatures remain at average for the time of year, and following the curve nicely.

http://ds.data.jma.g...e/pole30_n.html

It would be unusual to see anything other at this time of year. Any variance from the mean temperature is very small - but this changes significantly during the autumn. The time of interest for the winter will come from mid October onwards.

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/t60_90n_30_2011.pdf

[Weather-history]

Well the chart says we are still above the norm

[summer blizzard]

Well the chart says we are still above the norm

Very nice to see and probably explains why we are doing so well on the snow front this year (Siberia is above average).

It should also be noted that June and August were the 4th most -AO on record and the summer as a whole was the third most -AO summer on record.

It shall certainly be interesting to see the effect once the Polar Vortex really gets going.

[ZONE 51]

http://www.met.reading.ac.uk/Data/CurrentWeather/wcd/blog/a-cold-stratospheric-spring/

very interesting.

i was thinking about the rare december freeze 2010 and if it occurs again this winter then just how much more extreme it would be.

some unusual goings on-and the data records being broken show this-quite often it seems, this is not normal atmospheric behaviour when we look at the many years of normal winters.

[chionomaniac]

I tend not to look at the stratospheric temperature directly over the north Pole as I do not think that this gives a true accurate picture. I prefer to look at the average temperature from 60 degrees north as I feel that this gives a clearer picture. As one can see from the following link the average stratospheric Arctic temperature is rapidly cooling in line with what is expected.

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t60_90n_30_2011_merra.pdf

Of note is that Nasa have upgraded their modeling of this data so it will be interesting to see whether this is responsible for any variance this winter.

[summer blizzard]

I tend not to look at the stratospheric temperature directly over the north Pole as I do not think that this gives a true accurate picture. I prefer to look at the average temperature from 60 degrees north as I feel that this gives a clearer picture. As one can see from the following link the average stratospheric Arctic temperature is rapidly cooling in line with what is expected.

http://acdb-ext.gsfc..._2011_merra.pdf

Of note is that Nasa have upgraded their modeling of this data so it will be interesting to see whether this is responsible for any variance this winter.

Do we have the winter of 2009/2010 to look at?

[chionomaniac]

Do we have the winter of 2009/2010 to look at?

Any winter can be checked from 78-79 on this site

http://acdb-ext.gsfc.nasa.gov/Data_services/met/ann_data.html