By WUWT Regular “Just The Facts”
We are pleased to introduce WUWT’s newest addition, the WUWT Northern Polar Vortex Reference Page. We would like to dedicate this page to NBC News and John Holdren, who both seem to need all the help they can get in understanding Polar Vorticity.
“The stratospheric polar vortex is a large-scale region of air that is contained by a strong west-to-east jet stream that circles the polar region. This jet stream is usually referred to as the polar night jet. The polar vortex extends from the tropopause (the dividing line between the stratosphere and troposphere) through the stratosphere and into the mesosphere (above 50 km). Low values of ozone and cold temperatures are associated with the air inside the vortex.” NASA
“Polar vortices are ubiquitous atmospheric structures. In the Solar System, Earth, Mars, Venus, (Jupiter ), Saturn and its moon Titan are known to have well developed vortices in their polar regions at high altitude. These swirling structures are not always present in the atmosphere of a planetary body at all seasons, but they generally form in the winter hemisphere, when the latitudinal equator-to-pole temperature gradients are the strongest. For Earth, Mars, Saturn and Titan, therefore, the axial tilt determines the presence and seasonal variability of their polar vortices. This can be observed, for instance, by looking at the seasonality of the maximum speed of the circumpolar jets (see [6] for examples related to the Earth and Mars). Venus has a negligible axial tilt; therefore one would expect that the seasonality of its polar vortices is absent. Nonetheless, their seasonality seems to be induced by a dynamical phenomenon, linked to the presence of a quasi-bidiurnal oscillation at mid-latitudes, and extending to high latitudes, rather than by the obliquity of its rotation axis. This oscillation is observed in numerical simulations with global climate models, although its signature depends on the model as well as on model initialisation. A quasi-bidiurnal signal seems also to be present in some analysis of spacecraft data from Venus Express (see for instance [1]), although it has still to be understood whether its nature and origin are common to the oscillation observed in numerical simulations.” European Planetary Science Congress (Links and Jupiter added within)
Polar Vortices are “caused when an area of low pressure sits at the rotation pole of a planet. This causes air to spiral down from higher in the atmosphere, like water going down a drain.” Universe Today
“Long-term vortices are a frequent phenomenon in the atmospheres of fast rotating planets, like Jupiter and Saturn, for example. Venus rotates slowly, yet it has permanent vortices in its atmosphere at both poles. What is more, the rotation speed of the atmosphere is much greater than that of the planet. “We’ve known for a long time that the atmosphere of Venus rotates 60 times faster than the planet itself, but we didn’t know why. The difference is huge; that is why it’s called super-rotation. And we’ve no idea how it started or how it keeps going.
“The permanence of the Venus vortices contrasts with the case of the Earth. “On the Earth there are seasonal effects and temperature differences between the continental zones and the oceans that create suitable conditions for the formation and dispersal of polar vortices. On Venus there are no oceans or seasons, and so the polar atmosphere behaves very differently,” says Garate-Lopez.” Phys.org
“The stratospheric polar vortex shows quite a bit of day-to-day variability. This variability is caused by weather systems or large-scale waves that move upward from the troposphere into the stratosphere. In the left image (9 January 2010), we see some undulations along the edge of the polar vortex, but the vortex is generally centered on the North Pole. Two weeks later (center image on 23 January 2010) we see the center of the polar vortex pushed away from the North Pole. On a constant latitude circle, PV values are high in the eastern hemisphere and low in the western hemisphere. This is referred to as a wave-1 pattern (a wave-2 pattern can be seen in the vortex breakup section below). The wave-1 pattern develops in the troposphere and moves upward (propagates) into the stratosphere.
These stratospheric waves are forced by the large-scale mountain systems and the land-sea contrasts between the continents and oceans. During the northern winter, these waves are continuously forming and moving upward into the stratosphere. The waves can “break”, much like the waves on a beach. These wave-breaking events erode the vortex and keep the polar region warmer and ozone amounts higher. Often, parts of the polar vortex are pulled away from the main vortex. The image on the right (28 January 2010) shows this, where a large piece of the polar vortex was pulled away from the main vortex (green colored material at the bottom of the image). A comparison between the middle and right images also shows a slight contraction of the polar vortex because of these waves.”
“The polar vortex is a winter phenomena. It develops as the sun sets over the polar region and temperatures cool. During the spring, the sun rises and the absorption of solar radiation by ozone begins to heat the polar stratosphere. This heating eventually causes the vortex to disappear along with the polar night jet. However, this process is helped along by planetary-scale waves that propagate up from the troposphere. This wave event that drives the vortex breakup (or final warming) acts to also increase the temperature of the polar region and ozone levels. We mark the day of the vortex breakup when the winds around the vortex edge decrease below a particular value (about 15 m s -1on the 460 K potential temperature surface).”NASA
WUWT Northern Polar Vortex Reference Page offers focused view on the Northern Polar Vortex, whereas the WUWT Polar Vortex Reference Page offers a more broad overview of Global, Northern and Southern Polar Vorticity. When time permits, there will also be a WUWT Southern Polar Vortex Reference Page forthcoming. The following are some observation on recent Northern Polar Vortex activity from the WUWT Polar Vortex Reference Page:
Northern Hemisphere Temperature Analysis at 10 hPa/mb – Approximately 31,000 meters (101,700 feet) shows a high level split within the Stratospheric Polar Vortex on January 11th, 2014:
The split is also visible in Ozone Mixing Ratios at 30 hPa/mb – Approximately 23,700 meters (77,800 feet);
50 hPa/mb Height Analysis at Approximately 20,100 meters (66,000 feet):
70 hPa/mb Height Analysis – Approximately 18,000 meters (59,000 feet);
and 100 hPa/mb Height Analysis – Approximately 15,000 meters (49,000 feet):
Northern Hemisphere Area Where Temperature is Below 195K or -78C shows significant warming in the last few days;
The Vertical Cross Section of Geopotential Height Anomalies shows that the Polar Vortex has weakened significantly and the Arctic Oscillation swung to negative:
“The Arctic Oscillation refers to an opposing pattern of pressure between the Arctic and the northern middle latitudes. Overall, if the atmospheric pressure is high in the Arctic, it tends to be low in the northern middle latitudes, such as northern Europe and North America. If atmospheric pressure is low in the middle latitudes it is often high in the Arctic. When pressure is high in the Arctic and low in mid-latitudes, the Arctic Oscillation is in its negative phase. In the positive phase, the pattern is reversed.
Meteorologists and climatologists who study the Arctic pay attention to the Arctic Oscillation, because its phase has an important effect on weather in northern locations. The positive phase of the Arctic Oscillation brings ocean storms farther north, making the weather wetter in Alaska, Scotland, and Scandinavia and drier in the western United States and the Mediterranean. The positive phase also keeps weather warmer than normal in the eastern United States, but makes Greenland colder than normal.
In the negative phase of the Arctic Oscillation the patterns are reversed. A strongly negative phase of the Arctic Oscillation brings warm weather to high latitudes, and cold, stormy weather to the more temperate regions where people live.” NSIDC
In terms of why the Polar Vortex weakened and split, and the Atlantic Oscillation swung negative, there are likely several factors. the first being Planetary Waves, i.e. “The polar stratosphere and mesosphere are dynamically altered throughout the winter months by planetary wave activity and its interaction with the mean flow. An extreme interaction leads to polar vortex breakdown and a complete alteration in temperature from the lower stratosphere through the upper atmosphere. However, there are more regular disturbances where the dynamical interactions can alter the upper stratosphere and mesosphere without modification to the lower stratosphere; here these disturbances will be designated as Upper Stratospheric Lower Mesospheric (USLM) disturbances.” American Geophysical Union, Greer et al.
“The polar winter middle atmosphere is a dynamically active region that is driven primarily by wave activity. Planetary waves intermittently disturbed the region at different levels and the most spectacular type of disturbance is a major Sudden Stratospheric Warming (SSW). However, other types of extreme disturbances occur on a more frequent, intraseasonal basis. One such disturbances are synoptic-scale “weather events” observed in lidar and rocket soundings, soundings from the TIMED/SABER instrument and UK Meteorological Office (MetO) assimilated data. These disturbances are most easily identified near 42 km where temperatures are elevated over baseline conditions by a remarkable 50 K and an associated cooling is observed near 75 km. As these disturbances have a coupled vertical structure extending into the lower mesosphere, they are termed Upper Stratospheric/Lower Mesospheric (USLM) disturbances.”American Meteorological Society Conference, Greer et al. 2013
Recent Planetary Wave activity can be see on this Zonal Wave #1 Amplitude Jan, Feb, March Time Series;
Zonal Wave #2 Amplitude Jan, Feb, March Time Series;
and Zonal Wave #3 Amplitude Jan, Feb, March Time Series:
Another likely factor that weakened and split the Polar Vortex is Eddy Heat, i.e. “strong negative fluxes indicate poleward flux of heat via eddies. Multiple strong poleward episodes will result in a smaller polar vortex, Sudden Stratospheric Warmings and an earlier transition from winter to summer circulations. Relatively small flux amplitudes will result in a more stable polar vortex and will extend the winter circulation well into the Spring” NOAA
Here you can see that 10 day Averaged Eddy Heat Flux Towards The North Pole At 100mb neared a record daily maximum in early January:
A third potential factor in Polar Vortex behavior that has been proposed is that “geomagnetic activity (used as a measure of solar wind parameters)” plays a role in the “variability of large-scale climate patterns and on changes in the global temperature. We have found positive statistically significant correlations between global temperature and the distribution of surface temperature over Eurasia, the East and Equatorial Pacific and over the North Atlantic for the period 1966-2009 correspond to large-scale climate patterns defined by climate indices. We found very similar positive correlations between geomagnetic activity and the distribution of surface temperature in the mentioned regions. As an effect of geomagnetic storms, energetic particles penetrate from the magnetosphere into the region of the stratospheric polar vortex. The increase of temperature and pressure can be observed over northern Canada. The vortex shifts towards Europe, rotates counter-clockwise and the wind blows from the polar region over Greenland southwards. It diverts the warm flow proceeding northward over the Atlantic, eastward along the deep Icelandic low extending as far as the Barents Sea and takes part in warming Eurasia. The strengthened zonal flow from Siberia cools the western Pacific with the impact on the warming of the equatorial and eastern Pacific when also a distinct 1976-78 climate shift occurred. Processes in the Atlantic and Pacific play a significant role and a time delay (wind forcing over the previous 1-4 yr) appears to be the most important for the relocation of the oceanic gyres. Results showing statistically significant relations between time series for geomagnetic activity, for the sum of climate indices and for the global temperature help to verify findings concerning the chain of processes from the magnetosphere to the troposphere.” Studia Geophysica & Geodaetica, Bucha 2012
A Coronal Mass Ejection (CME); hit Earth around January 1st:
Ensemble WSA-ENLIL+Cone Model Evolution Movie for Median CME Input Parameters – Dynamic Pressure:
and the Magnetosphere was rocking and rolling:
However, there is limited evidence to support the influence of Solar activity on Polar Vorticity and in the past Leif has been dismissive of the potential that Solar influences on the upper atmosphere could influence Earth’s climate, i.e.:
Leif Svalgaard says: March 6, 2011 at 12:13 pm
Just The Facts says: March 6, 2011 at 11:03 am
indicate that the causative mechanism behind proton aurora precipitation during high dynamic pressure is connected to the compression of the magnetosphere, which is directly related to the solar wind dynamic pressure. [and other quotes]
“You keep bringing up influences on the upper atmosphere [which are not disputed – but makes for good fill-material that looks like science], but all of these things are either not related to climate at all or, at best, only marginally and unconvincing.
Again, your bar is much too low [to be generous].”
Regardless of the causes, it appears that the result is that an Upper Stratospheric/Lower Mesospheric (USLM) disturbance occurred, i.e. “USLM Disturbance criteria are established, based on stratopause warmings at the 2 hPa level, to create climatologies in both hemispheres that delineate their timing, frequency, and geographic location. USLM disturbances occur on average 2.3 times per winter in the Northern Hemisphere (NH)(November through March) and 1.6 times per winter in the Southern Hemisphere (SH)(May through September), persist on average for 8 days in the NH and only 4 days in the SH, occur most frequently in December (July) in the Northern (Southern) Hemisphere, and are predominantly located in the longitude sector between 0oE and 90oE in both hemispheres. This is the first work to show that all major Sudden Stratospheric Warmings (SSWs) over the 20.5 year data record are preceded by USLM disturbances. One third of USLM disturbances evolve into a major SSW; only 22% of minor SSWs evolve into a major SSW. USLM disturbances and minor SSWs illustrate, at times, similar occurrence statistics, but the minor warming criteria seem to include a more diverse range of dynamical conditions. USLM disturbances are more specific in their dynamical construct with strong baroclinicity being a necessary condition. Potential vorticity analysis indicates that all USLM events occur with planetary wave breaking and that subsequent baroclinic instability may lead to the development of USLM disturbances. A climatology of polar winter stratopause warmings and associated planetary wave breaking”. Greer et al. 2013
“The typical thermal structure of USLM disturbances is dipolar in nature at 2.0 hPa with strong thermal gradients across the polar vortex. From the assimilated data, we find that the geographic preference of the anomalously warm temperatures at 2.0 hPa are located on the East side of the polar low, while there is a related cool pool of air located on the West side. These geographic preferences and observed amplification in temperature help to support the proposed dynamical process of baroclinic instability. Indirect circulations are induced, and to preserve continuity, cells of ageostrophic and vertical motions occur well into the mesosphere, and potentially into the thermosphere. We find that the average frequency of USLM events is 1.63 events per season in the Northern Hemisphere. In addition, the assimilated data indicates that all Sudden Stratospheric Warmings (SSWs) are preceded by USLM events; SSW events occur with a frequency of 0.84 events per season (Northern Hemisphere). USLM disturbances persist from three to ten days and tend to precede SSW events by several days, although there may be multiple USLM disturbances prior to an SSW event occurring. Lastly we exhibit how USLM disturbances differ between the Northern and Southern poles, including differences in frequency and intensity. An open question is whether these frequent USLM polar winter disturbances impact the thermosphere and ionosphere. American Geophysical Union, Greer et al.
“Analysis of planetary wave breaking and EP-flux of individual and composite USLM events indicate an increase in breaking near the 0.1 hPa level, approximately 10 km above the extreme thermal anomaly at the stratopause in the days leading up to the peak of the event. Vertical coupling of the atmosphere during this event is illustrated in the progression of these events and their impact on the thermal structure, zonal mean wind, polar vortex and conditions that have the potential to support a secondary baroclinic instability (including the Charney-Stern criteria for instability the role of baroclinic/barotropic instabilities). In addition, USLM disturbances appear to have front-like behavior analogous to the troposphere. Broader impacts of these disturbances and the dynamics associated with them influence gravity wave generation/propagation, vertical air motion, chemical tracer transport, precondition of the atmosphere for SSWs and the potential to couple with the thermosphere through tides. American Meteorological Society Conference, Greer et al. 2013
The Upper Stratosphere Lower Mesosphere (USLM) Disturbance can be seen on this Jan, Feb, March Zonal Temperature Anomaly Time Series;
and the impact of the USLM can be seen in the rapid increase in 10-hPa/mb Height Temperature Anomalies – Atmospheric Temperature Anomalies At Approximately 31,000 meters (101,700 feet) over East Asia:
You can see more on current Northern Polar Vortex conditions on the new WUWT Northern Polar Vortex Reference Page. I addition, if you have not had the opportunity to review WUWT’s other Reference Pages it is highly recommended:
- Atmosphere Page
- Atmospheric Oscillation Page
- ENSO (El Nino/La Nina Southern Oscillation) Page
- “Extreme Weather” Page
- Geomagnetism Page
- Global Climate Page
- Global Temperature Page
- Ocean Page
- Oceanic Oscillation Page
- Polar Vortex Page
- Paleoclimate Page
- Potential Climatic Variables Page
- WUWT Northern Polar Vortex Reference Page.
- Northern Regional Sea Ice Page
- Sea Ice Page
- Solar Page
- Spencer and Braswell Papers
- Tornado Page
- Tropical Cyclone Page
- US Climatic History Page
- US Weather Page
Please note that WUWT cannot vouch for the accuracy of the data within the Reference Pages, as WUWT is simply an aggregator. All of the data is linked from third party sources. If you have doubts about the accuracy of any of the graphs on the WUWT Reference Pages, or have any suggested additions or improvements to any of the pages, please let us know in comments below.
Robert Clemenzi says:
January 18, 2014 at 2:14 pm
This doesn’t show it (click on earth lower left to change variables): http://earth.nullschool.net
Thanks, JTFW.
Daniel Vogler says: January 18, 2014 at 1:02 pm
National Oceanic & Atmospheric Administration (NOAA) – Earth System Research Laboratory (ESRL) – Click the pic to view at source[/caption]
I would like to see the Reference page include the Mountain Torque events pic as well. here is where to get it. MTs lead to geopotential waves.
Added, i.e. “Vertical and Zonal Integral Of Mountain Torque – 90 Days”
[caption id="" align="alignnone" width="578"]
Also, Wave#3 isnt necessary. It does not play a significant role in SSWs.
Removed
Thank you very much, any other suggested improvements would be most appreciated.
Robert Clemenzi says: January 18, 2014 at 2:14 pm
PhysicalGeography.net – Click the pic to view at source[/caption]
NOAA – National Weather Service – Climate Prediction Center – Click the pic to view at source[/caption]
NOAA – National Weather Service – Climate Prediction Center – Click the pic to view at source[/caption]
NOAA – National Weather Service – Climate Prediction Center – Click the pic to view at source[/caption]
The descriptions above talk of the vortex causing cold air to sink and provide more cold air to the pole. The implication is that this some how makes the pole colder. I don’t understand how this is possible. In general, the stratosphere gets warmer with increasing height, even over the poles. As a result, the sinking air should make the poles warmer.
You are correct that “In general, the stratosphere gets warmer with increasing height”;
[caption id="" align="alignnone" width="578"]
however, “the polar vortex extends from the tropopause (the dividing line between the stratosphere and troposphere) through the stratosphere and into the mesosphere (above 50 km). Low values of ozone and cold temperatures are associated with the air inside the vortex.” NASA
If you review the descending Temperature Analyses in my recent article A Sober Look At The Northern Polar Vortex, it is apparent that air within the Polar Vortex is much colder that the air around it, e.g.:
Starting at 10 hPa/mb – Approximately 31,000 meters (101,700 feet) here we have a Height Analysis showing the low pressure area;
[caption id="" align="alignnone" width="578"]
a Temperature Analysis showing the cold area;
[caption id="" align="alignnone" width="578"]
and Ozone Mixing Ratio map showing the “Ozone Hole” within it:
[caption id="" align="alignnone" width="578"]
In addition, there is the consideration of “potential temperature”. Basically, this means that air gets warmer as it moves toward the surface because of the change in pressure – about 9.8K per kilometer. As a result, air from the mesosphere (0°C at about 50km), if moved to the surface, would be over 450°C!
But there isn’t the same “change in pressure” within the vortex, as the walls of the vortex maintain the low pressure as the cold air descends. However, when the vortex breaks up, the pressures equalize and we get a Sudden Stratospheric Warming, i.e.:
“A stratospheric sudden warming is perhaps one of the most radical changes of weather that is observed on our planet. Within the space of a week, North Pole temperatures can increase by more than 50 K (90°F). For example, on 17 January 2009 the temperature at the North Pole near 30 km was about 200 K. Over a 5-day period, the temperature increased to 260 K (a change of 60 K or 108°F).
These stratospheric sudden warmings are caused by atmospheric waves that originate in the troposphere. The waves are forced by the large-scale mountain systems of the northern hemisphere and the land-sea contrasts between the continents and oceans. The waves are also characterized by their very large scales, typically referred to as planetary-scale waves. The stratospheric wind structure filters the smaller scale waves, only allowing the planetary waves to propagate into the stratosphere. As the waves move upward into the stratosphere they have two effects: first they will often push the polar vortex away from the North Pole—bringing warmer midlatitude air poleward, and second, they produce a downward motion field that also warms the polar region.” NASA
Nice job JTF!
Great posts and exchanges with take aways, thanks all.
One more acronym to add to the ever increasing list too,,,,, USLM 🙂
Daniel Vogler says: January 18, 2014 at 1:24 pm
the Solar influence on the Stratosphere is linked to the type of QBO phase, a decent correlation of SSWs and the QBO phase and solar Flux
http://f1.nwstatic.co.uk/forum/uploads/monthly_01_2014/post-10577-0-14746500-1389168133.jpg
I actually argued the solar – QBO link with Leif a few years ago, but didn’t make any headway.
“The Influence of the Solar Cycle and QBO on the Late-Winter Stratospheric Polar Vortex”
Camp et al. 2006:
“A statistical analysis of 51 years of NCEP–NCAR reanalysis data is conducted to isolate the separate effects of the 11-yr solar cycle (SC) and the equatorial quasi-biennial oscillation (QBO) on the Northern Hemisphere (NH) stratosphere in late winter (February–March). In a four-group [SC maximum (SC-max) versus minimum (SC-min) and east-phase versus west-phase QBO] linear discriminant analysis, the state of the westerly phase QBO (wQBO) during SC-min emerges as a distinct least-perturbed (and coldest) state of the stratospheric polar vortex, statistically well separated from the other perturbed states. Relative to this least-perturbed state, the SC-max and easterly QBO (eQBO) each independently provides perturbation and warming as does the combined perturbation of the SC-max–eQBO. All of these results (except the eQBO perturbation) are significant at the 95% confidence level as confirmed by Monte Carlo tests; the eQBO perturbation is marginally significant at the 90% level. This observational result suggests a conceptual change in understanding the interaction between solar cycle and QBO influences: while previous results imply a more substantial interaction, even to the extent that the warming due to SC-max is reversed to cooling by the eQBO, results suggest that the SC-max and eQBO separately warm the polar stratosphere from the least-perturbed state. While previous authors emphasize the importance of segregating the data according to the phase of the QBO, here the same polar warming by the solar cycle is found regardless of the phase of the QBO.
The polar temperature is positively correlated with the SC, with a statistically significant zonal mean warming of approximately 4.6 K in the 10–50-hPa layer in the mean and 7.2 K from peak to peak. This magnitude of the warming in winter is too large to be explainable by UV radiation alone. The evidence seems to suggest that the polar warming in NH late winter during SC-max is due to the occurrence of sudden stratospheric warmings (SSWs), as noted previously by other authors. This hypothesis is circumstantially substantiated here by the similarity between the meridional pattern and timing of the warming and cooling observed during the SC-max and the known pattern and timing of SSWs, which has the form of large warming over the pole and small cooling over the midlatitudes during mid- and late winter. The eQBO is also known to precondition the polar vortex for the onset of SSWs, and it has been pointed out by previous authors that SSWs can occur during eQBO at all stages of the solar cycle. The additional perturbation due to SC-max does not double the frequency of occurrence of SSWs induced by the eQBO. This explains why the SC-max/eQBO years are not statistically warmer than either the SC-max/wQBO or SC minimum/eQBO years. The difference between two perturbed (warm) states (e.g., SC-max/eQBO versus SC-min/eQBO or SC-max/eQBO versus SC-max/wQBO), is small (about 0.3–0.4 K) and not statistically significant. It is this small difference between perturbed states, both warmer than the least-perturbed state, that in the past has been interpreted either as a reversal of SC-induced warming or as a reversal of QBO-induced warming.”
“The mechanism of QBO’s interaction with the polar stratosphere is better understood, and yet many of the reported observational results have not been explained.Holton and Tan (1980, 1982) discovered what is now called the Holton – Tan effect. They found that in composites, according to the phase of the equatorial QBO at 50 hPa, the polar winter temperature is warmer and the polar vortex is more perturbed by planetary waves when the equatorial QBO is in its easterly phase than in its westerly phase. For a possible mechanism, they cited the work of Tung and Lindzen (1979a) on the effect of the position of the zero-wind line on the stationary planetary waves: As the zero-wind line moves more poleward during eQBO, the westerly waveguide for stationary waves is narrowed and located more poleward. This tends to focus the planetary waves more poleward, making the polar vortex more disturbed and hence warmer. Our understanding of wave – mean flow interaction in the stratosphere has progressed considerably since the late 1970s. Instead of the quasi-linear picture of wave – mean interaction in which the zero-wind line plays a crucial role, it is now understood that the dynamics is highly nonlinear in the stratosphere, and planetary waves break in surf zones (McIntyre and Palmer 1984). Nevertheless, the planetary waves do tend to break more poleward during the QBO easterly phase than during the westerly phase when the waveguide is wider and the wave flux is directed more equatorward. Holton and Tan (1980) divided the winter into early winter (November – December) and late winter (January – March). They found, using 16 years of data, that in early winter wavenumber-1 amplitude at 50 hPa is about 40% greater in eQBO than in wQBO, at the 99% confidence level in a Student’s t test. This positive result was later questioned by Naito and Hirota (1997, hereafter NH97) who found that the Holton – Tan result for 1962/63 – 1977/78 failed to hold in the longer record up to 1993/94. NH97 conjectured that the difference found by Holton and Tan was due to the solar cycle because the period used by them happens to contain two solar minima and one maximum. They therefore suggested that Holton and Tan’s result could not be valid in general, it being applicable only to periods with more solar minima than maxima. Gray et al.(2001)’s findings echo these: For the shorter 26-yr period of 1964 – 90, with a bias toward the solar minimum, the correlation between January – February North Polartemperature in the lower stratosphere with the equatorial QBO wind is 0.4 (the negative sign meaning that the pole is warmer during easterly QBO years), but reduces to 0.25 for the 44 winters from 1955 to 1999, including four full solar cycles. Holton and Tan (1980) also found that during late winter the behavior of wave-number 2 was unexpectedly opposite, being about 60% stronger, in the composite mean, during the wQBO than in the eQBO at 96% confidence level. However, when four more years were added to the sample, they found that the significance level dropped to about 90%.”
Conclusions:
“1) There is a very well separated state of the polar stratosphere, which occurs during the confluence of a solar cycle minimum and westerly QBO; we denote this state as the “
least-perturbed state.” This state is statistically distinguished from all other (perturbed) states at more than the 99% confidence level.
2) Relative to this least-perturbed state, a solar maximum warms the pole by a mean of approximately 4.6 K (7.2 K peak to peak) during the wQBO and also during the eQBO; both results are statistically significant at more than the 95% confidence level. The statistically significant discriminant spatial patterns of the warming take the form of the structure
associated with sudden stratospheric warmings.
3) The above result shows that the solar cycle warms the polar stratosphere by the same amount regardless of the phase of the QBO. It then follows that the stratification of the data according to the phase of the QBO is not necessary in order to see the SC response, except for its necessity in defining the reference state.
4) Relative to the least-perturbed state, easterly QBO also warms the pole by approximately 4 K but at a lower confidence level of 90%. This lowered significance may be due to the fact that the preconditioning of the SSW by a QBO may depend on the equatorial wind at several height layers (Gray et al. 2001; Gray 2003). The spatial structure is also similar to that of the SSW.
5) Statistically significant results are obtained when perturbations are measured relative to the least-perturbed state. Previous confusion over possible reversals of solar cycle warming or of the Holton – Tan QBO mechanism are now seen to arise from the comparison of one perturbed state with another perturbed state. These differences are not statistically significant due to the similarity of each of the perturbations. In Fig. 9, the differences between perturbed states are denoted by dashed arrows. Two group LDAs between the perturbed states (not
shown) show that there is an approximately 0.4-K warming from SC-min/eQBO to SC-max/eQBO (i.e., SC perturbation during eQBO) and an approximately 0.3-K cooling from SC-max/wQBO to SC-max/eQBO (i.e., QBO perturbation during the SC-max). The latter result (the small cooling) has been interpreted as a reversal of the Holton – Tan mechanism; however, both of these results have very low statistical significances and so the signs of the
warming should not be taken seriously.”
“The Influence of the Solar Cycle and QBO on the Late-Winter Stratospheric Polar Vortex, Lu et al.
“SIGNALS OF SOLAR WIND DYNAMIC PRESSURE IN THE NORTHERN ANNULAR MODE AND THE EQUATORIAL STRATOSPHERIC QUASI-BIENNIAL OSCILLATION”
They “report statistically measurable responses of the Northern Annular Mode (NAM) and the equatorial stratospheric Quasi-biennial Oscillation (QBO) to solar wind dynamic pressure. When December to January solar wind dynamic pressure is high, the Northern Hemispheric (NH) circulation response is marked by a stronger polar vortex and weaker sub-tropical jet in the upper to middle stratosphere. As the winter progresses, the Arctic becomes colder and the jet anomalies shift poleward and downward. In spring, the polar stratosphere becomes anomalously warmer. At solar maxima, significant positive correlations are found between December to January solar wind dynamic pressure and the mid- to late winter NAM all the way from the surface to 20 hPa, implying a strengthened polar vortex, reduced Brewer-Dobson circulation and enhanced stratosphere-troposphere coupling. The combined effect of high solar UV irradiance and high solar wind dynamic pressure in the NH mid- to late winter is enhanced westerlies in the extratropics and weaker westerlies in the subtropics, indicating that more planetary waves are refracted towards the equator. At solar minima, there is no correlation in the NH winter but negative correlations between December to January solar wind dynamic pressure and the NAM are found only in the stratosphere during spring. Statistical evidence of a possible modulation of the equatorial stratospheric Quasi-biennial Oscillation (QBO) by the solar wind dynamic pressure is also provided. When solar wind dynamic pressure is high, the QBO at 30-70 hPa is found to be preferably more easterly during July to October. These lower stratospheric easterly anomalies are primarily linked to the high frequency component of solar wind dynamic pressure with periods shorter than 3-years. In annually and seasonally aggregated daily averages, the signature of solar wind dynamic pressure in the equatorial zonal wind is characterized by a vertical three-cell anomaly pattern with westerly anomalies both in the troposphere and the upper stratosphere and easterly anomalies in the lower stratosphere. This anomalous behavior in tropical winds is accompanied by a downward propagation of positive temperature anomalies from the upper stratosphere to the lower stratosphere over a period of a year. These results suggest that the solar wind dynamic pressure exerts a seasonal change of the tropical upwelling which results in a systemic modulation of the annual cycle in the lower stratospheric temperature, which in turn affects the QBO during Austral late winter and spring. These results suggest possible multiple solar inputs. Their combined effect in the stratosphere may cause refraction/redistribution of upward wave propagation and result in projecting the solar wind signals onto the NAM and the QBO. The route by which the effects of solar wind forcing might propagate to the lower atmosphere is yet to be understood.”
“Possible solar wind effect on the northern annular mode and northern hemispheric circulation during winter and spring, Lu et al.
Found “statistically measurable responses of atmospheric circulation to solar wind dynamic pressure are found in the Northern Hemisphere (NH) zonal-mean zonal wind and temperature, and on the Northern Annular Mode (NAM) in winter and spring. When December to January solar wind dynamic pressure (P sw DJ) is high, the circulation response is marked by a stronger polar vortex and weaker sub-tropical jet in the upper to middle stratosphere. As the winter progresses, the Arctic becomes colder and the jet anomalies shift poleward and downward. In spring, the polar stratosphere becomes anomalously warmer. At solar maxima, significant positive correlations are found between P swDJ and the middle to late winter NAM all the way from the surface to 20 hPa, implying a strengthened polar vortex, reduced Brewer–Dobson circulation and enhanced stratosphere-troposphere coupling. The combined effect of high solar UV irradiance and high solar wind dynamic pressure in the NH middle to late winter is enhanced westerlies in the extratropics and weaker westerlies in the subtropics, indicating that more planetary waves are refracted toward the equator. At solar minima, there is no correlation in the NH winter but negative correlations between P swDJ and the NAM are found only in the stratosphere during spring. These results suggest possible multiple solar inputs that may cause refraction/redistribution of upward wave propagation and result in projecting the solar wind signals onto the NAM. The route by which the effects of solar wind forcing might propagate to the lower atmosphere is yet to be understood.”
There appear to be correlations between solar wind dynamic pressure and the NAM and QBO. However, Leif argued that there is no known mechanism whereby ”the effects of solar wind forcing might propagate to the lower atmosphere”. At this point I would argue that Polar Vortex Perturbation is at least plausible.
Chuck L says: January 18, 2014 at 12:08 pm
Kavli Institute for Theoretical Physics – University of California – Click the pic to view at source[/caption]
Can the polar vortex be considered an eddy which detaches from the circumpolar vortex? Thanks.
No, the Stratospheric Polar Vortex and Circumpolar Vortex are separate and distinct phenomena occurring in different locations and altitudes on Earth:
This and this are animations of the current Polar Vortex and this is an animation of what it looks like when a Polar Vortex breaks up. Conversely, this and this are animations of the Circumpolar Vortex.
This image should help to visualize the separation:
[caption id="" align="alignnone" width="410"]
“Even a simplified model of the Earth’s atmosphere that has only two layers at different altitudes reproduces observed features of the general circulation such as jet streams, storm tracks, and trade winds. Colors in the image represent the wind vorticity averaged over the two levels. Image by Brad Marston.” this and KITP
Chuck L says: January 18, 2014 at 12:08 pm
Lyndon State College Atmospheric Sciences – Click the pic to view at source[/caption]
It is also helpful to note that:Planetary Vorticity “is zero at equator, is maximum at pole (one revolution per day)” and “is always positive (cyclonic)”. Lyndon State College Atmospheric Sciences
[caption id="" align="alignnone" width="500"]
“The cold experienced in early January was actually a result of the polar vortex weakening, becoming warmer and therefore releasing its powerful chill beyond its normal reach through the northern climes, NOAA says.”
Funny, that sounds just like my ex. As she becomes warmer, she releases a powerful chill beyond her normal reach. Saying that something is more likely to release a powerful chill when it is warmer may sound like a contradiction, but CO2 is a devious molecule that can do all sorts of magical things. Why it can cause global heat waves or prolonged global cooling depending on its mood. To be truthful, we have absolutely no clue which one will happen next. But right after it happens, we will be quick to say, “I told you so!”
Not only does Saturn have a Polar Vortex, it is inexplicably hexagonal.
It has got to be something like a natural harmonic, but it is a spinning hexagonal storm 20,000 miles in diameter that has been there whenever we’ve looked for the past 30 years. There are signs of it in Voyager photos. But Cassini got a long sustained view of it in it’s Polar Mission phase a couple of years ago. See also Astronomy Pic of the Day Feb. 20, 2013
Very neat JTF. Thanks, it is good info to have.
Sigh! I remember when we just had winter.
You know? It got cold on and off for a few months. ☺ Then we had something called spring and summer, although here in Canuckistan the lines were often blurred and if you did not know the actual date, you might not know what season it really was. And then we had winter again. Now we have the polar vortex. A hex on the vortex. ☺
No PV here in southern Alberta these a past few days. Was 11°C here and sunshine all day.
Thanks again. Good stuff.
CAS
Speaking of “Polar Vortex”, the governor of OH has declared an “energy emergency” and is calling out the National Guard. They can’t get fuel oil and propane to people fast enough so he has suspended regulations that limit “in service” hours for drivers. Here is the order:
http://www.ema.ohio.gov/Documents/Releases/2014/20140118_StateOfEnergyEmergency.pdf
United Kingdom 27 January will be under the polar vortex.
http://losyziemi.pl/wp-content/uploads/2014/01/NH_TMP_10mb_372-530×397.gif
http://losyziemi.pl/niezwykly-taniec-wiru-polarnego-ktory-silnie-reaguje-na-aktywnosc-slonca
http://geo.phys.spbu.ru/materials_of_a_conference_2012/STP2012/Veretenenko_%20et_all_Geocosmos2012proceedings.pdf
In the weak vortex (2010 to 2040) jumping cosmic radiation strongly influence the state of the ozone over the Arctic Circle.
http://cosmicrays.oulu.fi/webform/query.cgi?startday=01&startmonth=01&startyear=2014&starttime=00%3A00&endday=19&endmonth=01&endyear=2014&endtime=00%3A00&resolution=Automatic+choice&picture=on
Ionizing radiation is focused on the polar circle, and increases in the period of low solar activity.
http://terra2.spacenvironment.net/~raps_ops/current_files/rtimg/dose.15km.png
Current polar vortex at the height of 17 km.
http://earth.nullschool.net/jp/#current/wind/isobaric/70hPa/orthographic=-347.07,95.63,319
Good work! Thanks.
one can have “a phenomenon”,” two or more phenomena”, but not “a phenomena [sic].
Mr. Layman here. (Maybe I should change my screen-name to that?)
Thanks.
Have I got this basically right?
1. “Polar Vortex” is nothing new.
2. “Polar Vortex” has not been commonly used to describe winter weather events to the public.
3. “Polar Vortex” is now being used to make what is a normal winter weather event seem “abnormal” or “weird” to the public?
(I realize that 1 and 2 may be asking for more of an opinion than a provable fact.)
DANG!
Typo!
“(I realize that 1 and 2 may be asking for more of an opinion than a provable fact.)”
Should be:
“(I realize that 2 and 3 may be asking for more of an opinion than a provable fact.)”
(Maybe instead of “TYPO!” I should have said “BRAINO)!”?
Thanks for all the information. I am going to bookmark this post and return to it, for there is no way my brain cells can absorb all this information all at once. However it will be a nice, rich feast to peruse from time to time. In around ten years, if I’m still alive, I may start to comprehend the many different layers of weather and how they all interact.
I tend to stick to nice, simple surface maps. Judging from those maps the low pressure areas in the arctic do seem to run along the edge of the ice, especially in the fall when the air over the ice is rapidly getting colder, while the air over the northern tendrils of the Gulf Stream remains close to freezing. I’ve seen 2m temperature isotherm differences as great as sixty degrees (plus thirty as opposed to minus thirty) squished very close together along the Siberian coast. Then, as the seas north of Siberia freeze from east to west, the storms loose their power further and further west. The lows seem to weaken over ice the same way hurricanes weaken over land.
Of course this is all happening down on ground level, and not up where the jet streams cruise.
This is fantastic work and information. Here is what I want everybody to do to appreciate this recent Arctic air mass and the real reason for it better. Go to the link below, which will allow you to access reanalysis data(weather maps) from NOAA going back to 1948.
Put in a starting date of (year)1976 (month)11 (day)26 (cycle) 00
Let’s try an ending date of 1977 02 02
http://www.hpc.ncep.noaa.gov/ncepreanal/
Look how many times the “Polar Vortex” becomes displaced by thousands of miles and on 3 separate occasions in January, 1977, dives into the United States very similar to what we saw earlier this month.
Tell me again what CO2 levels were back in the Winter of 1976/77.
Here’s what’s going on. The weather/climate is following something like a 30 year natural cycle of warming and cooling. It’s blatantly obvious to anybody with open eyes/brains using pattern recognition looking at a global temperature graph going back 120 years.
We finished the warming phase just over a decade ago which meant that by the late 1990’s, those with bad memories and or too lazy or biased to look at the weather/climate during previous cooling and warming periods were making assumptions based on ignorance of the past.
So now that our planet is back in the cooling phase, which correlates well with some oceanic indices like the PDO that flip/reverse in sign every 30 years (but also “may” have a new element involving the sun which makes it more interesting) we have those ignorant of the past, coming up with ignorant statements like this:
“A growing body of evidence suggests that the kind of extreme cold being experienced by much of the United States as we speak is a pattern that we can expect to see with increasing frequency as global warming continues”
John Holden really did say this.
http://www.examiner.com/article/white-house-polar-…
The main reason for this recent extreme cold was similar to the more numerous extreme cold outbreaks of the Winter of 76/77……………and many, many other ones in our history which featured massive blobs of Arctic air and a deep, cutoff upper level low being displaced very far south of their origin.
It had nothing to do with humans, CO2 or global warming.
Gunga Din says: January 19, 2014 at 1:40 pm
memegenerator.net – Click the pic to view at source[/caption]
1. “Polar Vortex” is nothing new.
Correct, the book Living Age from 1853 references the Polar Vortex and Google Scholar brings back 16,100 citations for Polar Vortex”:
http://scholar.google.com/scholar?hl=en&q=%22polar+vortex%22&btnG=&as_sdt=1%2C31&as_sdtp=
2. “Polar Vortex” has not been commonly used to describe winter weather events to the public.
Correct, prior to 2014 the Google Trend for “Polar Vortex” is almost dead:
http://www.google.com/trends/explore#q=polar%20vortex&date=1%2F2004%20121m&cmpt=q
However, it is important to note this January 25, 2011, New York Times article Cold Jumps Arctic ‘Fence,’ Stoking Winter’s Fury and associated NYT blog post Frigid Winters and the Polar Vortex, which both reference the Polar Vortex.
3. “Polar Vortex” is now being used to make what is a normal winter weather event seem “abnormal” or “weird” to the public?
Correct, though a lot of this can be attributed to sensationalism versus an organized disinformation campaign, i.e.:
John Holdren, Jennifer Francis and numerous others are currently disingenuously trying to use the Polar Vortex to explain why warming causes cooling. However, I encourage them, as the warming causes cooling meme is a sure fire loser. All but a brainwashed lemming can see that John, Jennifer and company are contorting themselves to try to cram polar breakouts and freezing temps into the rapidly crumbling Catastrophic Anthropogenic Global Warming Narrative. One does not need to understand the intricacies of Polar Vorticity in order to know when one is being lied to. I expect that when we see the next round of survey results, the Polar Vortex and Ship of Fools memes will result in “Global warming denial” hitting new highs, i.e. Global warming denial hits a six-year high:
“The percentage of Americans who believe global warming is human-caused has also declined, and now stands at 47 percent, a decrease of 7 percent since 2012.”
“The obvious question is, what happened over the last year to produce more climate denial?
According to both Anthony Leiserowitz of Yale and Ed Maibach of George Mason, the leaders of the two research teams, the answer may well lie in the so-called global warming “pause” — the misleading idea that global warming has slowed down or stopped over the the past 15 years or so. This claim was used by climate skeptics, to great effect, in their quest to undermine the release of the U.N. Intergovernmental Panel on Climate Change’s Fifth Assessment Report in September 2013 — precisely during the time period that is in question in the latest study.”
“Nonetheless, widely publicized “pause” claims may well have shaped public opinion. “Beginning in September, and lasting several months, coincident with the release of the IPCC report, there was considerable media attention to the concept of the ‘global warming pause,’” observes Maibach. “It is possible that this simple — albeit erroneous — idea helped to convince many people who were previously undecided to conclude that the climate really isn’t changing.”
“Even more likely, however,” Maibach adds, “is that media coverage of the ‘pause’ reinforced the beliefs of people who had previously concluded that global warming is not happening, making them more certain of their beliefs.”
“Journalists take heed: Your coverage has consequences. All those media outlets who trumpeted the global warming “pause” may now be partly responsible for a documented decrease in Americans’ scientific understanding.”
In summary, I am not concerned with the media’s interpretation, or more commonly misinterpretation, of the Polar Vortex, as it plays into our hands by showing more people how little we really know about Earth’s climate system. This image sums up my perspective on the media’s embrace of the Polar Vortex:
[caption id="attachment_54067" align="alignnone" width="568"]
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Thanks. I can’t always follow the science but I do better with the “PR”.
(Mexican beer caused the Polar Vortex? 😎