Technical Teleconnective Papers

[sebastiaan1973]

Central Pacific El Niño, the “subtropical bridge,†and Eurasian climate

This study contributes to the discussion on possible effects of El Niño on North Atlantic/European regional climates. We use NCEP/NCAR reanalysis data to show how the two different types of El Niños (the central Pacific, or CP, and the east Pacific, or EP) result in remarkably different European winter temperature anomalies, specifically weak warming during EP and significant cooling during CP El Niños, the latter being associated with a negative phase of the winter North Atlantic Oscillation (NAO). Our results diverge from former suggestions addressing the weakened stratospheric polar vortex as the dominant factor contributing to the El Niño/NAO teleconnection. We propose a tropospheric bridge as the mechanism primarily responsible for the establishment of a negative NAO phase and of associated cold European winters. This mechanism includes the subtropical jet (STJ) waveguide being activated only during CP El Niños, when anomalous convective heating occurs near the edge of the Pacific warm pool. Under these conditions the STJ is enhanced by planetary wave flux divergence in the subtropical upper troposphere, providing favorable conditions for the propagation of a wave number 5 disturbance around the subtropical Northern Hemisphere. This wave contributes to weakening of the Azores High and, hence, to the negative NAO phase. As global warming scenarios project an increase in the frequency of CP El Niño events, the distinctive nature of this mechanism implies that the probability of cold European winters may increase as well in future decades.

[lorenzo]

Had to read this abstract a couple of times to get the idea. Interesting to see another study linking ENSO and NAO.

http://onlinelibrary.wiley.com/doi/10.1002/qj.1889/abstract

[jethro]

Another to add to the list:

"Scientists have uncovered evidence for another natural cycle that, like El Niño and La Niña, shifts Pacific Ocean winds and currents and rearranges rainfall and weather patterns around the globe. The newly detected cycle recurs every 100 years, less frequently than the two-to-seven year El Niño-Southern Oscillation. But its existence, if confirmed, offers another fundamental cog to understand the ocean-atmosphere machinery that regulates worldwide rain, droughts, wildfires, floods, landslides, fisheries, and storms."

http://www.whoi.edu/...nus/feature/pco

[sebastiaan1973]

http://icdm2012.csp.escience.cn/dct/attach/Y2xiOmNsYjpwZGY6Mjc0NTE= Nice presentation by Adam Scaife. More can be found here http://icdm2012.csp.escience.cn/dct/page/65537

[lorenzo]

Some excellent data held in this one..

Role of Planetary Wave Reflection on the variability of Tropospheric

Weather and Circulation Pattern

Debashis Nath, Chen WEN, Wei KE

[lorenzo]

The structure and evolution of the Arctic stratospheric polar vortex is assessed

during opposing phases of, primarily, the El Niño–Southern Oscillation (ENSO) and the

Quasiâ€Biennial Oscillation (QBO), but the 11 year solar cycle and winters following

large volcanic eruptions are also examined. The analysis is performed by taking 2â€D

moments of vortex potential vorticity (PV) fields which allow the area and centroid of

the vortex to be calculated throughout the ERAâ€40 reanalysis data set (1958–2002).

Composites of these diagnostics for the different phases of the natural forcings are then

considered. Statistically significant results are found regarding the structure and

evolution of the vortex during, in particular, the ENSO and QBO phases. When compared

with the more traditional zonal mean zonal wind diagnostic at 60°N, the momentâ€based

diagnostics are far more robust and contain more information regarding the state of the

vortex. The study details, for the first time, a comprehensive sequence of events which map

the evolution of the vortex during each of the forcings throughout an extended winter

period.

http://www-atm.physi...ell2011_jgr.pdf

Table extracted from above is useful for analogs for QBO, ENSO, Solar Cycle, SSWs,Volcanic Activity.

Edited October 9, 2012 by lorenzo

[chionomaniac]

Thanks for the latest papers lorenzo.

[lorenzo]

That last one is an excellent read, talk about things being right before your eyes - it was on the Berlin site.. ! Doh !

[chionomaniac]

Transfer of papers from the strat thread regarding MJO / NAO linkage as I think that this thread could be a very useful depository for further reading for years to come.

http://www.ecmwf.int/newsevents/meetings/informal_seminars/abstracts/2012/Brunet.pdf

http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0CEcQFjAH&url=http%3A%2F%2Fwww.wmo.int%2Fpages%2Fprog%2Farep%2Fwwrp%2Fnew%2Fdocuments%2F7_Lin_The_Atlantc.ppt&ei=OQdwUOu6D6TD0QWQtYDwBA&usg=AFQjCNF0FBfpQZB9yTzWqSNo67hOisbG8w&sig2=2PbrAs5WPCtWWr-Ku7QXIA

http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&ved=0CE0QFjAI&url=http%3A%2F%2Fwww.wmo.int%2Fpages%2Fprog%2Farep%2Fwwrp%2Fnew%2Fdocuments%2FLin_PDP_A.ppt&ei=OQdwUOu6D6TD0QWQtYDwBA&usg=AFQjCNFonnr_Dk7fBxA61ZPJRa4qpRbpyA&sig2=v9X7zY1LCk4M301ABb_LLg

[lorenzo]

Will park this one in here, gave it a read through this afternoon and a lot of it is beyond my interpretation as of yet.

Couple of new processes devised Tropospheric and Stratospheric control of the BDC, differing elements of the BDC itself shallow and deep. Resonant Cavity in the Polar Vortex and also touches on Gravity Waves in the Mesosphere, excluded but the subject of a future paper.

Figs 5 and 6 are interesting as factors are altered to highlight upwelling/downwelling and also wave amplitudes.

Very technical !

gerber-JAS-2012.pdf

[Isolated Frost]

Would like to thank everybody that has posted in this thread, as a 15 year old, it's so helpful and some of the papers have been really interesting, bookmark territory. KIU Lorenzo and Chiono especially- superb work and hopefully a very valuable collection to look back on!

[lorenzo]

Variability of the Brewer-Dobson circulation’s meridional and vertical branch using Aura/MLS water vapor.

acpd-12-21291-2012.pdf

Ongoing Interactive discussion here

[Isolated Frost]

Great paper above- really helpful.

Special request here, anyone got any links on the MJO, AAM and Torques areas? Really trying to touch up my knowledge after forgetting some over winter and would love it if anyone could help. Also an explanation of a poleward flux AAM? Really appreciate everything going on here.

[lorenzo]

Will have a dig shortly IF and post up what I can find.

GWO

wb08_final.pdf

MJO

WH04.pdf

Some of the others are too big to upload will look up the links and add them.

Edited October 23, 2012 by lorenzo

[lorenzo]

Couple of other papers to add in looking at Wave 1 and Wave 2 interactions with the Vortex, cannot write PV as this is getting muddled in my head with Potential vorticity now..

A comparative study of the major sudden stratospheric warmings in the Arctic winters 2003/2004–2009/2010

http://www.google.co.uk/url?sa=t&rct=j&q=a%20comparative%20study%20of%20the%20major%20sudden%20stratospheric%20warmings%20in%20the%20arctic%20winters%202003%2F2004%E2%80%932009%2F2010&source=web&cd=2&cad=rja&ved=0CCkQFjAB&url=http%3A%2F%2Fwww.atmos-chem-phys.net%2F12%2F8115%2F2012%2Facp-12-8115-2012.pdf&ei=4NqYUMHjNqLO0QWikoH4CA&usg=AFQjCNGp8jdznVu0Yf8DH-_qYTh1JnGs1A

This is a bulletin from a paper released at SPARC, cannot find the PDF in the public domain yet.

Bancala_SPARC_2012.pdf

[Mark Bayley]

Was reading one of my climate books for a uni module and came across a section on the QBO, which linked to a review paper that i thought might be of interest to some (its quite long at 52 pages)

http://adrem.org.cn/Faculty/GongDY/class2008/QBO.pdf

Unfortunately given its a Geography degree we only look at ENSO and variations in the NAO and AO. Although given i shall be expected to read a number of articles on them i'm hopeful i might be able to contribute a little to this thread!

Abstract

The quasi-biennial oscillation (QBO) dominates the variability of the equatorial stratosphere (∼16–50 km) and is easily seen as downward propagating easterly and westerly wind regimes, with a variable period averaging approximately 28 months. From a fluid dynamical perspective, the QBO is a fascinating example of a coherent, oscillating mean flow that is driven by propagating waves with periods unrelated to that of the resulting oscillation. Although the QBO is a tropical phenomenon, it affects the stratospheric flow from pole to pole by modulating the effects of extratropical waves. Indeed, study of the QBO is inseparable from the study of atmospheric wave motions that drive it and are modulated by it. The QBO affects variability in the mesosphere near 85 km by selectively filtering waves that propagate upward through the equatorial stratosphere, and may also affect the strength of Atlantic hurricanes. The effects of the QBO are not confined to atmospheric dynamics. Chemical constituents, such as ozone, water vapor, and methane, are affected by circulation changes induced by the QBO. There are also substantial QBO signals in many of the shorter-lived chemical constituents. Through modulation of extratropical wave propagation, the QBO has an effect on the breakdown of the wintertime stratospheric polar vortices and the severity of high-latitude ozone depletion. The polar vortex in the stratosphere affects surface weather patterns, providing a mechanism for the QBO to have an effect at the Earth's surface. As more data sources (e.g., wind and temperature measurements from both ground-based systems and satellites) become available, the effects of the QBO can be more precisely assessed. This review covers the current state of knowledge of the tropical QBO, its extratropical dynamical effects, chemical constituent transport, and effects of the QBO in the troposphere (∼0–16 km) and mesosphere (∼50–100 km). It is intended to provide a broad overview of the QBO and its effects to researchers outside the field, as well as a source of information and references for specialists. The history of research on the QBO is discussed only briefly, and the reader is referred to several historical review papers. The basic theory of the QBO is summarized, and tutorial references are provided.

[03jtrickey]

I've got to write three extended essays for my Geography degree...and I can write about pretty much anything. One of my modules was on seasonal prediction so I'm going to attempt something along the lines of "Will improved knowledge of stratosphere-troposphere interactions increase the skill of seasonal forecasts for UK winters?". I've really enjoyed following the stratosphere thread this winter (many thanks to chionomaniac & GP) so I thought I'd do something that's topical and that I'm interested in!

I've just come across a very recent paper published online on 13 January 2013 which may be of interest.

http://www.nature.co...l/ngeo1698.html

"Enhanced seasonal forecast skill following stratospheric sudden warmings

Advances in seasonal forecasting have brought widespread socio-economic benefits. However, seasonal forecast skill in the extratropics is relatively modest1, prompting the seasonal forecasting community to search for additional sources of predictability2, 3. For over a decade it has been suggested that knowledge of the state of the stratosphere can act as a source of enhanced seasonal predictability; long-lived circulation anomalies in the lower stratosphere that follow stratospheric sudden warmings are associated with circulation anomalies in the troposphere that can last up to two months4, 5. Here, we show by performing retrospective ensemble model forecasts that such enhanced predictability can be realized in a dynamical seasonal forecast system with a good representation of the stratosphere. When initialized at the onset date of stratospheric sudden warmings, the model forecasts faithfully reproduce the observed mean tropospheric conditions in the months following the stratospheric sudden warmings. Compared with an equivalent set of forecasts that are not initialized during stratospheric sudden warmings, we document enhanced forecast skill for atmospheric circulation patterns, surface temperatures over northern Russia and eastern Canada and North Atlantic precipitation. We suggest that seasonal forecast systems initialized during stratospheric sudden warmings are likely to yield significantly greater forecast skill in some regions."

Edited January 21, 2013 by 03jtrickey

[iceicebaby]

I've got to write three extended essays for my Geography degree...and I can write about pretty much anything. One of my modules was on seasonal prediction so I'm going to attempt something along the lines of "Will improved knowledge of stratosphere-troposphere interactions increase the skill of seasonal forecasts for UK winters?". I've really enjoyed following the stratosphere thread this winter (many thanks to chionomaniac & GP) so I thought I'd do something that's topical and that I'm interested in!

I've just come across a very recent paper published online on 13 January 2013 which may be of interest.

http://www.nature.co...l/ngeo1698.html

"Enhanced seasonal forecast skill following stratospheric sudden warmings

Advances in seasonal forecasting have brought widespread socio-economic benefits. However, seasonal forecast skill in the extratropics is relatively modest1, prompting the seasonal forecasting community to search for additional sources of predictability2, 3. For over a decade it has been suggested that knowledge of the state of the stratosphere can act as a source of enhanced seasonal predictability; long-lived circulation anomalies in the lower stratosphere that follow stratospheric sudden warmings are associated with circulation anomalies in the troposphere that can last up to two months4, 5. Here, we show by performing retrospective ensemble model forecasts that such enhanced predictability can be realized in a dynamical seasonal forecast system with a good representation of the stratosphere. When initialized at the onset date of stratospheric sudden warmings, the model forecasts faithfully reproduce the observed mean tropospheric conditions in the months following the stratospheric sudden warmings. Compared with an equivalent set of forecasts that are not initialized during stratospheric sudden warmings, we document enhanced forecast skill for atmospheric circulation patterns, surface temperatures over northern Russia and eastern Canada and North Atlantic precipitation. We suggest that seasonal forecast systems initialized during stratospheric sudden warmings are likely to yield significantly greater forecast skill in some regions."

Already seen it around here i think. Anyhow, interesting stuff

[03jtrickey]

Already seen it around here i think. Anyhow, interesting stuff

I can't find reference to it using a forum search, although it may well have been mentioned.

[Interitus]

Rather than link individual work, a welter of interesting papers can be found here - http://wwwoa.ees.hok...-NAM/index.html

There are only a few papers on this page and the urls have a surplus "/people/yamazaki" to delete so be sure to look at the links to the author homepages.

Ogi's and Yamazaki's are in English, but Tachibana's is in Japanese, fortunately the power of google translate leads to his list - http://www.bio.mie-u...chi/papers.html

[Interitus]

There is another wodge of interesting stuff here http://ljp.lasg.ac.cn/dct/page/65558

[sebastiaan1973]

Today I received a suggestion to read the following article. I thought I share this article over here as well.

 

Stratospheric response to Arctic sea ice retreat and associated planetary wave propagation changes

www.tellusa.net/index.php/tellusa/article/download/19375/pdf_1

 

The stratospheric response to the observed Arctic sea ice retreat is analysed based on European Centre for Medium-Range Weather Forecast (ECMWF) Re-Analysis Interim (ERA-Interim) atmospheric data from 19792012. It is shown that changes in August/September sea ice concentration impact on tropospheric and stratospheric geopotential heights in the following winter. During low ice phases a negative tropospheric Arctic Oscillation pattern is found, which is connected to a weakened stratospheric polar vortex and warmer stratospheric temperatures. Furthermore, the analysis reveals enhanced upward EP fluxes due to planetary waves for low ice conditions. Strong stratospheric anomalies in the Atlantic/European region are associated with a weaker polar vortex. Low ice periods are connected with additional tropospheric wave energy excitation in the Pacific/North America region and influence the stratosphere through three-dimensional planetary wavepropagation.

Edited August 9, 2013 by sebastiaan1973

[lorenzo]

New Acronym alert and I wondered when we would see a paper that brought the mesosphere into things.

 

USLM - Upper Stratosphere Lower Mesosphere.

 

http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50289/abstract

 

This work presents a climatology of synoptic-scale disturbances in the upper stratosphere lower mesosphere (USLM) based on 20.5 years of assimilated data analyses from the U. K. Meteorological Office (1991–2012). 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 0^oE and 90^oE 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

 

 

[chionomaniac]

New Acronym alert and I wondered when we would see a paper that brought the mesosphere into things.

 

USLM - Upper Stratosphere Lower Mesosphere.

 

http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50289/abstract

 

This work presents a climatology of synoptic-scale disturbances in the upper stratosphere lower mesosphere (USLM) based on 20.5 years of assimilated data analyses from the U. K. Meteorological Office (1991–2012). 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 0^oE and 90^oE 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

I am not surprised to see that given the way MT's lead to wave breaking sailing to the top of the strat surf zone before breaking into the core of the vortex and disrupting down from then onwards.

[jonboy]

Is there a translation for the last two posts?