Influence of the upward wave activity flux in the winter 2012/2013 on the Arctic polar vortex

2019 ◽  
Author(s):  
Vladimir V. Zuev ◽  
Ekaterina Savelieva
Keyword(s):  
Polar Vortex ◽  
Wave Activity ◽  
The Arctic ◽  
Wave Activity Flux

Intraseasonal and Interdecadal Jet Shifts in the Northern Hemisphere: The Role of Warm Pool Tropical Convection and Sea Ice

2014 ◽  
Vol 27 (17) ◽  
pp. 6497-6518 ◽  
Author(s):  
Steven B. Feldstein ◽  
Sukyoung Lee
Keyword(s):  
Sea Ice ◽  
Polar Vortex ◽  
Warm Pool ◽  
Wave Activity ◽  
Arctic Sea Ice ◽  
Tropical Convection ◽  
The Arctic ◽  
Stratospheric Polar Vortex ◽  
Arctic Sea ◽  
Wave Activity Flux

Abstract This study uses cluster analysis to investigate the interdecadal poleward shift of the subtropical and eddy-driven jets and its relationship to intraseasonal teleconnections. For this purpose, self-organizing map (SOM) analysis is applied to the ECMWF Interim Re-Analysis (ERA-Interim) zonal-mean zonal wind. The resulting SOM patterns have time scales of 4.8–5.7 days and undergo notable interdecadal trends in their frequency of occurrence. The sum of these trends closely resembles the observed interdecadal trend of the subtropical and eddy-driven jets, indicating that much of the interdecadal climate forcing is manifested through changes in the frequency of intraseasonal teleconnection patterns. Two classes of jet cluster patterns are identified. The first class of SOM pattern is preceded by anomalies in convection over the warm pool followed by changes in the poleward wave activity flux. The second class of patterns is preceded by sea ice and stratospheric polar vortex anomalies; when the Arctic sea ice area is reduced, the subsequent planetary wave anomalies destructively interfere with the climatological stationary waves. This is followed by a decrease in the vertical wave activity flux and a strengthening of the stratospheric polar vortex. An increase in sea ice area leads to the opposite chain of events. Analysis suggests that the positive trend in the Arctic Oscillation (AO) up until the early 1990s might be attributed to increased warm pool tropical convection, while the subsequent reversal in its trend may be due to the influence of tropical convection being overshadowed by the accelerated loss of Arctic sea ice.

scholarly journals The Major Stratospheric Sudden Warming of January 2013: Analyses and Forecasts in the GEOS-5 Data Assimilation System

2015 ◽  
Vol 143 (2) ◽  
pp. 491-510 ◽  
Author(s):  
Lawrence Coy ◽  
Steven Pawson
Keyword(s):  
Data Assimilation ◽  
Polar Vortex ◽  
Wave Activity ◽  
Time Data ◽  
Weather System ◽  
Stratospheric Sudden Warming ◽  
The Pacific ◽  
Data Assimilation System ◽  
Wave Activity Flux ◽  
Assimilation System

Abstract The major stratospheric sudden warming (SSW) of 6 January 2013 is examined using output from the NASA Global Modeling and Assimilation Office (GMAO) Goddard Earth Observing System version 5 (GEOS-5) near-real-time data assimilation system (DAS). GEOS-5 analyses showed that the SSW of January 2013 was a major warming by 1200 UTC 6 January, with a wave-2 vortex-splitting pattern. Upward wave activity flux from the upper troposphere (~23 December 2012) displaced the ~10-hPa polar vortex off the pole in a wave-1 pattern, enabling the poleward advection of subtropical values of Ertel potential vorticity (EPV) into a developing anticyclonic circulation region. While the polar vortex subsequently split (wave-2 pattern) the wave-2 forcing [upward Eliassen–Palm (EP) flux] was smaller than what was found in recent wave-2, SSW events, with most of the forcing located in the Pacific hemisphere. Investigation of a rapidly developing tropospheric weather system over the North Atlantic on 28–29 December 2012 showed strong transient upward wave activity flux from the storm with influences up to 10 hPa; however, the Pacific hemisphere wave forcing remained dominate at this time. Results from the GEOS-5 five-day forecasts showed that the forecasts accurately predicted the major SSW of January 2013. The overall success of the 5-day forecasts provides motivation to produce regular 10-day forecasts with GEOS-5, to better support studies of stratosphere–troposphere interaction.

scholarly journals Analysis of the Arctic polar vortex dynamics during the sudden stratospheric warming in January 2009

2021 ◽  
Vol 67 (2) ◽  
pp. 134-146
Author(s):  
V. V. Zuev ◽  
E. S. Savelieva ◽  
A. V. Pavlinsky
Keyword(s):  
Wind Speed ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Wave Activity ◽  
The Arctic ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Mean Wind Speed ◽  
The Mean ◽  
Middle Stratosphere

The Arctic polar vortex is often affected by wave activity during its life cycle. The planetary Rossby waves propagating from the troposphere to the stratosphere occasionally lead to the displacement or splitting of the polar vortex, accompanied by sudden stratospheric warming (SSW). In January 2009, one of the largest SSWs was observed in the Arctic. In this work, the dynamics of the polar vortex during the 2009 SSW is considered using a new method that allows one to estimate the vortex area, the wind speed at the vortex edge, the mean temperature and ozone mass mixing ratio inside the vortex, based on the fact that the Arctic vortex edge at the 50 and 10 hPa pressure levels is determined by the geopotential values, respectively, 19.5. 104 and 29.5. 104 m2 /s2 , using the ERA5 reanalysis data. The application of this method is justified for the Arctic polar vortex, which is characterized by significant variability, especially during the period of its splitting. The splitting of the polar vortex in 2009 was observed on January 24 and 28, respectively, in the middle and lower stratosphere. About a week after the splitting, the vortices became closer in characteristics to small cyclones, which completely collapsed within 1–3 weeks. The influence of planetary wave activity on the polar vortex does not always lead to its breakdown. Short-term splitting of the polar vortex is sometimes observed for several days after which the polar vortex strengthens again and PSCs form inside the vortex. Such a recovery of the polar vortex is most likely to occur in the winter. Based on the analysis of the dynamics of the Arctic polar vortex for 1979–2020 and using the example of the 2009 SSW, we showed that when the vortex area decreases to less than 10 million km2 and the mean wind speed at the vortex edge decreases below 30 and 45 m/s, respectively, in the lower and middle stratosphere, the polar vortex becomes a small cyclone (with significantly higher temperatures within it), which usually collapses within 3 weeks.

scholarly journals Quasigeostrophic Transient Wave Activity Flux: Updated Climatology and Its Role in Polar Vortex Anomalies

2010 ◽  
Vol 67 (10) ◽  
pp. 3164-3189 ◽  
Author(s):  
Mototaka Nakamura ◽  
Minoru Kadota ◽  
Shozo Yamane
Keyword(s):  
Lower Troposphere ◽  
Polar Vortex ◽  
Wave Activity ◽  
Vertical Flux ◽  
Storm Tracks ◽  
Mean Flow ◽  
Transient Wave ◽  
Upper Troposphere ◽  
Wave Flux ◽  
Wave Activity Flux

Abstract The climatology of transient wave activity flux defined by Plumb has been calculated for each calendar month, for high-frequency (HF) and low-frequency (LF) waves, using the NCAR–NCEP reanalyses for both hemispheres. Wave activity flux of both HF and LF waves shows upward propagation of waves from the lower troposphere into the upper troposphere, then into the lower stratosphere during the summer and at least up to the midstratosphere during other seasons. While the upward flux emanating from the lower troposphere is particularly large in the two storm tracks in the Northern Hemisphere (NH), it is large in most of the extratropics in the Southern Hemisphere (SH). The HF waves radiate equatorward most noticeably in the upper troposphere, whereas the LF waves do not show visible signs of equatorward radiation. The total horizontal flux is generally dominated by the advective flux that represents the eddy enstrophy advection by the mean flow and appears predominantly pseudoeastward. Divergence of the wave activity flux exhibits discernible large-scale characteristics at the lowest level in both hemispheres and in the upper troposphere in the NH. The divergence field indicates acceleration of the pseudoeastward mean flow near the surface in both hemispheres. In the NH, acceleration and deceleration, respectively, of the pseudoeastward mean flow in the storm tracks and downstream of the storm tracks in the upper troposphere are found. Seasonal variations in the wave flux are substantial in the NH but relatively minor in the SH. In the NH, the wave flux fields exhibit generally larger values during the cold months than during warm months. Also, the latitudes at which large wave flux values are seen are higher during warm months, as the jets and storm tracks shift northward from the winter to the summer. Anomalously large vertical flux of both HF and LF wave activity propagating up from the lower troposphere throughout the troposphere and stratosphere in the northern flank of the North Atlantic storm track is found to precede anomalous deceleration in the NH winter polar vortex, while anomalously small vertical flux in the same area precedes anomalous acceleration of the vortex. The accompanying horizontal flux anomalies tend to counteract the action of the anomalous vertical flux. These cases are found to be dissipation of strong anomalies in the polar vortex. The anomalous flux divergence does not prove the active role of the waves in the anomalous change in the polar vortex, however. No signs of the wave flux originating from specific areas preceding anomalous change in the polar vortex are found for the SH.

Stratosphere–Troposphere Coupling and Links with Eurasian Land Surface Variability

2007 ◽  
Vol 20 (21) ◽  
pp. 5335-5343 ◽  
Author(s):  
Judah Cohen ◽  
Mathew Barlow ◽  
Paul J. Kushner ◽  
Kazuyuki Saito
Keyword(s):  
Land Surface ◽  
Planetary Wave ◽  
Vertical Component ◽  
Polar Vortex ◽  
Subsequent Development ◽  
Wave Activity ◽  
The Arctic ◽  
Surface Circulation ◽  
The Arctic Oscillation ◽  
Hemisphere Winter

Abstract A diagnostic of Northern Hemisphere winter extratropical stratosphere–troposphere interactions is presented to facilitate the study of stratosphere–troposphere coupling and to examine what might influence these interactions. The diagnostic is a multivariate EOF combining lower-stratospheric planetary wave activity flux in December with sea level pressure in January. This EOF analysis captures a strong linkage between the vertical component of lower-stratospheric wave activity over Eurasia and the subsequent development of hemisphere-wide surface circulation anomalies, which are strongly related to the Arctic Oscillation. Wintertime stratosphere–troposphere events picked out by this diagnostic often have a precursor in autumn: years with large October snow extent over Eurasia feature strong wintertime upward-propagating planetary wave pulses, a weaker wintertime polar vortex, and high geopotential heights in the wintertime polar troposphere. This provides further evidence for predictability of wintertime circulation based on autumnal snow extent over Eurasia. These results also raise the question of how the atmosphere will respond to a modified snow cover in a changing climate.

scholarly journals The Role of Standing Waves in Driving Persistent Anomalies of Upward Wave Activity Flux

2015 ◽  
Vol 28 (24) ◽  
pp. 9941-9954 ◽  
Author(s):  
Oliver Watt-Meyer ◽  
Paul J. Kushner
Keyword(s):  
Linear Part ◽  
Standing Waves ◽  
Polar Vortex ◽  
Wave Activity ◽  
Stratospheric Polar Vortex ◽  
Interference Phenomenon ◽  
Vortex Strength ◽  
Nonlinear Part ◽  
Persistent Anomalies ◽  
Wave Activity Flux

Abstract Northern Hemisphere stratospheric polar vortex strength variability is known to be largely driven by persistent anomalies in upward wave activity flux. It has also been shown that attenuation and amplification of the stationary wave is the primary way in which wave activity flux varies. This study determines the structure of the wave anomalies that interfere with the climatological wave and drive this variability. Using a recently developed spectral decomposition it is shown that fixed-node standing waves are the primary drivers of the “linear interference” phenomenon. This is particularly true for the low-frequency component of the upward wave activity flux. The linear part of the flux is shown to be more persistent than the total flux and has significant tropospheric standing wave precursors that lead changes in the strength of the stratospheric polar vortex. Evidence is presented that current-generation high-top climate models are able to credibly simulate this variability in wave activity fluxes and the connection to polar vortex strength. Finally, the precursors to displacement and split sudden stratospheric warmings are examined. Displacement events are found to be preceded by about 25 days of anomalously high upward wave activity flux forced by standing waves amplifying the climatology. Split events have more short-lived wave activity flux precursors, which are dominated by the nonlinear part of the flux.

scholarly journals Tropospheric forcing of the boreal polar vortex splitting in January 2003

2010 ◽  
Vol 28 (11) ◽  
pp. 2133-2148 ◽  
Author(s):  
D. H. W. Peters ◽  
P. Vargin ◽  
A. Gabriel ◽  
N. Tsvetkova ◽  
V. Yushkov
Keyword(s):  
Rossby Wave ◽  
Planetary Wave ◽  
Winter Season ◽  
Polar Vortex ◽  
Wave Activity ◽  
The Arctic ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Stratospheric Polar Vortex ◽  
Wave Trains

Abstract. The dynamical evolution of the relatively warm stratospheric winter season 2002–2003 in the Northern Hemisphere was studied and compared with the cold winter 2004–2005 based on NCEP-Reanalyses. Record low temperatures were observed in the lower and middle stratosphere over the Arctic region only at the beginning of the 2002–2003 winter. Six sudden stratospheric warming events, including the major warming event with a splitting of the polar vortex in mid-January 2003, have been identified. This led to a very high vacillation of the zonal mean circulation and a weakening of the stratospheric polar vortex over the whole winter season. An estimate of the mean chemical ozone destruction inside the polar vortex showed a total ozone loss of about 45 DU in winter 2002–2003; that is about 2.5 times smaller than in winter 2004–2005. Embedded in a winter with high wave activity, we found two subtropical Rossby wave trains in the troposphere before the major sudden stratospheric warming event in January 2003. These Rossby waves propagated north-eastwards and maintained two upper tropospheric anticyclones. At the same time, the amplification of an upward propagating planetary wave 2 in the upper troposphere and lower stratosphere was observed, which could be caused primarily by those two wave trains. Furthermore, two extratropical Rossby wave trains over the North Pacific Ocean and North America were identified a couple of days later, which contribute mainly to the vertical planetary wave activity flux just before and during the major warming event. It is shown that these different tropospheric forcing processes caused the major warming event and contributed to the splitting of the polar vortex.

scholarly journals The Diurnal Variation in Stratospheric Ozone from MACC Reanalysis, ERA-Interim, WACCM, and Earth Observation Data: Characteristics and Intercomparison

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 625
Author(s):  
Ansgar Schanz ◽  
Klemens Hocke ◽  
Niklaus Kämpfer ◽  
Simon Chabrillat ◽  
Antje Inness ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Model Systems ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Observation Data ◽  
High Latitudes ◽  
Free Running

In this study, we compare the diurnal variation in stratospheric ozone of the MACC (Monitoring Atmospheric Composition and Climate) reanalysis, ECMWF Reanalysis Interim (ERA-Interim), and the free-running WACCM (Whole Atmosphere Community Climate Model). The diurnal variation of stratospheric ozone results from photochemical and dynamical processes depending on altitude, latitude, and season. MACC reanalysis and WACCM use similar chemistry modules and calculate a similar diurnal cycle in ozone when it is caused by a photochemical variation. The results of the two model systems are confirmed by observations of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) experiment and three selected sites of the Network for Detection of Atmospheric Composition Change (NDACC) at Mauna Loa, Hawaii (tropics), Bern, Switzerland (midlatitudes), and Ny-Ålesund, Svalbard (high latitudes). On the other hand, the ozone product of ERA-Interim shows considerably less diurnal variation due to photochemical variations. The global maxima of diurnal variation occur at high latitudes in summer, e.g., near the Arctic NDACC site at Ny-Ålesund, Svalbard. The local OZORAM radiometer observes this effect in good agreement with MACC reanalysis and WACCM. The sensed diurnal variation at Ny-Ålesund is up to 8% (0.4 ppmv) due to photochemical variations in summer and negligible during the dynamically dominated winter. However, when dynamics play a major role for the diurnal ozone variation as in the lower stratosphere (100–20 hPa), the reanalysis models ERA-Interim and MACC which assimilate data from radiosondes and satellites outperform the free-running WACCM. Such a domain is the Antarctic polar winter where a surprising novel feature of diurnal variation is indicated by MACC reanalysis and ERA-Interim at the edge of the polar vortex. This effect accounts for up to 8% (0.4 ppmv) in both model systems. In summary, MACC reanalysis provides a global description of the diurnal variation of stratospheric ozone caused by dynamics and photochemical variations. This is of high interest for ozone trend analysis and other research which is based on merged satellite data or measurements at different local time.

scholarly journals Seasonal prediction of the boreal winter stratosphere

2021 ◽  
Author(s):  
Alice Portal ◽  
Paolo Ruggieri ◽  
Froila M. Palmeiro ◽  
Javier García-Serrano ◽  
Daniela I. V. Domeisen ◽  
...  
Keyword(s):  
Southern Oscillation ◽  
Polar Vortex ◽  
Seasonal Prediction ◽  
Wave Activity ◽  
Boreal Winter ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Eddy Heat Flux ◽  
Prediction Systems ◽  
Model Database

AbstractThe predictability of the Northern Hemisphere stratosphere and its underlying dynamics are investigated in five state-of-the-art seasonal prediction systems from the Copernicus Climate Change Service (C3S) multi-model database. Special attention is devoted to the connection between the stratospheric polar vortex (SPV) and lower-stratosphere wave activity (LSWA). We find that in winter (December to February) dynamical forecasts initialised on the first of November are considerably more skilful than empirical forecasts based on October anomalies. Moreover, the coupling of the SPV with mid-latitude LSWA (i.e., meridional eddy heat flux) is generally well reproduced by the forecast systems, allowing for the identification of a robust link between the predictability of wave activity above the tropopause and the SPV skill. Our results highlight the importance of November-to-February LSWA, in particular in the Eurasian sector, for forecasts of the winter stratosphere. Finally, the role of potential sources of seasonal stratospheric predictability is considered: we find that the C3S multi-model overestimates the stratospheric response to El Niño–Southern Oscillation (ENSO) and underestimates the influence of the Quasi–Biennial Oscillation (QBO).

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