QUASI-STATIONARY PLANETARY WAVES IN MID-LATITUDE STRATOSPHERE–MESOSPHERE IN WINTER 2011-2020

The 10-year climatology (2011–2020) of quasi-stationary planetary waves in the mid-latitude stratosphere and mesosphere (40–50N, up to 90 km) has been analyzed. Longitude–altitude sections of geopotential height and ozone have been obtained using the Aura MLS satellite data. It is found that stationary wave 1 propagates into the mesosphere from the North American High and Icelandic Low, which are adjacent surface pressure anomalies in the structure of stationary wave 2. Unexpectedly, the strongest pressure anomaly in the Aleutian Low region does not contribute to the stationary wave 1 formation in the mesosphere. The vertical phase transformations of stationary waves in geopotential height and ozone show inconsistencies that should be studied separately.

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The Icelandic Low as a Predictor of the Gulf Stream North Wall Position

Journal of Physical Oceanography ◽

10.1175/jpo-d-14-0244.1 ◽

2016 ◽

Vol 46 (3) ◽

pp. 817-826 ◽

Cited By ~ 15

Author(s):

Alejandra Sanchez-Franks ◽

Sultan Hameed ◽

Robert E. Wilson

Keyword(s):

Gulf Stream ◽

Southern Oscillation ◽

Time Lags ◽

Grand Banks ◽

The North ◽

Cape Hatteras ◽

Pressure Anomaly ◽

Icelandic Low ◽

North Wall ◽

Wall Position

AbstractThe Gulf Stream’s north wall east of Cape Hatteras marks the abrupt change in velocity and water properties between the slope sea to the north and the Gulf Stream itself. An index of the north wall position constructed by Taylor and Stephens, called Gulf Stream north wall (GSNW), is analyzed in terms of interannual changes in the Icelandic low (IL) pressure anomaly and longitudinal displacement. Sea surface temperature (SST) composites suggest that when IL pressure is anomalously low, there are lower temperatures in the Labrador Sea and south of the Grand Banks. Two years later, warm SST anomalies are seen over the Northern Recirculation Gyre and a northward shift in the GSNW occurs. Similar changes in SSTs occur during winters in which the IL is anomalously west, resulting in a northward displacement of the GSNW 3 years later. Although time lags of 2 and 3 years between the IL and the GSNW are used in the calculations, it is shown that lags with respect to each atmospheric variable are statistically significant at the 5% level over a range of years. Utilizing the appropriate time lags between the GSNW index and the IL pressure and longitude, as well as the Southern Oscillation index, a regression prediction scheme is developed for forecasting the GSNW with a lead time of 1 year. This scheme, which uses only prior information, was used to forecast the GSNW from 1994 to 2015. The correlation between the observed and forecasted values for 1994–2014 was 0.60, significant at the 1% level. The predicted value for 2015 indicates a small northward shift of the GSNW from its 2014 position.

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Dynamics of Eddy-Driven Low-Frequency Dipole Modes. Part III: Meridional Displacement of Westerly Jet Anomalies during Two Phases of NAO

Journal of the Atmospheric Sciences ◽

10.1175/jas3998.1 ◽

2007 ◽

Vol 64 (9) ◽

pp. 3232-3248 ◽

Cited By ~ 36

Author(s):

Dehai Luo ◽

Tingting Gong ◽

Yina Diao

Keyword(s):

Theoretical Model ◽

Storm Track ◽

Low Frequency ◽

Stationary Wave ◽

Negative Phase ◽

Stationary Waves ◽

The North ◽

Westerly Jet ◽

Two Phases ◽

The North Atlantic Oscillation

Abstract In this paper, the north–south variability of westerly jet anomalies during the two phases of the North Atlantic Oscillation (NAO) is examined in a theoretical model. It is found that the north–south variability of the zonal mean westerly anomaly results from the interaction between the eddy-driven anomalous stationary waves with a dipole meridional structure (NAO anomalies) and topographically induced climatological stationary waves with a monopole structure, which is dependent upon the phase of the NAO. The westerly jet anomaly tends to shift northward during the positive NAO phase but southward during the negative phase. Synoptic-scale eddies tend to maintain westerly jet anomalies through the excitation of NAO anomalies, but the climatological stationary wave and its position relative to the eddy-driven anomalous stationary wave appear to dominate the north–south shift of westerly jet anomalies. On the other hand, it is shown that when the climatological stationary wave ridge is located downstream of the eddy-driven anomalous stationary wave, the storm track modulated by the NAO pattern splits into two branches for the negative phase, in which the northern branch is generally stronger than the southern one. However, the southern one can be dominant as the relative position between anomalous and climatological stationary waves is within a moderate range. The storm track for the positive phase tends to drift northeastward when there is a phase difference between the NAO anomaly and climatological stationary wave ridge downstream. Thus, it appears that the relationship between the NAO jets and storm tracks can be clearly seen from the present theoretical model.

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Dynamics of an Interhemispheric Teleconnection across the Critical Latitude through a Southerly Duct during Boreal Winter*

Journal of Climate ◽

10.1175/jcli-d-14-00425.1 ◽

2015 ◽

Vol 28 (19) ◽

pp. 7437-7456 ◽

Cited By ~ 29

Author(s):

Sen Zhao ◽

Jianping Li ◽

Yanjie Li

Keyword(s):

Indian Ocean ◽

South Asia ◽

Southern Africa ◽

Western Indian Ocean ◽

Wave Theory ◽

Stationary Wave ◽

Boreal Winter ◽

Stationary Waves ◽

The North ◽

Critical Latitude

Abstract In this study, an interhemispheric teleconnection pattern across the critical latitude from southern Africa through South Asia to the North Pacific was revealed in boreal winter monthly averaged 250-hPa streamfunction fields obtained from both the 40-yr ECMWF Re-Analysis (ERA-40) and the NCEP–NCAR reanalysis data from 1957/58 to 2001/02. Classical Rossby wave theory for zonally varying flow in which the effects of the basic-state meridional wind are ignored predicts that stationary Rossby waves cannot propagate across easterlies. To elucidate the underlying mechanisms responsible for this interhemispheric teleconnection, the theoretical basis for stationary wave propagation across the critical latitude is considered, taking into account meridional ambient flow. The theoretical results suggest that the southerly flow over East Africa, the western Indian Ocean, and South Asia creates a path for the northward propagation of stationary waves across the critical latitude. Stationary wavenumber and group velocity analysis, ray tracing, and simple model experiments applied to nearly realistic boreal winter mean flows confirm that disturbances excited in southern Africa and the western Indian Ocean can propagate across the critical latitude to South Asia through the southerly duct and then continue downstream along the North African–Asian subtropical jet.

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The quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-6511-2014 ◽

2014 ◽

Vol 14 (13) ◽

pp. 6511-6522 ◽

Cited By ~ 12

Author(s):

D. Scheiben ◽

B. Tschanz ◽

K. Hocke ◽

N. Kämpfer ◽

S. Ka ◽

...

Keyword(s):

Water Vapor ◽

Satellite Data ◽

North Atlantic Ocean ◽

Polar Vortex ◽

Wave Activity ◽

Planetary Waves ◽

Boreal Winter ◽

The North ◽

Latitude Circle ◽

Microwave Radiometers

Abstract. This study investigates the characteristics of the quasi 16-day wave in the mesosphere during boreal winter 2011/2012 using observations of water vapor from ground-based microwave radiometers and satellite data. The ground-based microwave radiometers are located in Seoul (South Korea, 37° N), Bern (Switzerland, 47° N) and Sodankylä (Finland, 67° N). The quasi 16-day wave is observed in the mesosphere at all three locations, while the dominant period increases with latitude from 15 days at Seoul to 20 days at Sodankylä. The observed evolution of the quasi 16-day wave confirms that the wave activity is strongly decreased during a sudden stratospheric warming that occurred in mid-January 2012. Using satellite data from the Microwave Limb Sounder on the Aura satellite, we examine the zonal characteristics of the quasi 16-day wave and conclude that the observed waves above the midlatitudinal stations Seoul and Bern are eastward-propagating s = −1 planetary waves with periods of 15 to 16 days, while the observed oscillation above the polar station Sodankylä is a standing wave with a period of approximately 20 days. The strongest relative wave amplitudes in water vapor during the investigated time period are approximately 15%. The wave activity varies strongly along a latitude circle. The activity of the quasi 16-day wave in mesospheric water vapor during boreal winter 2011/2012 is strongest over northern Europe, the North Atlantic Ocean and northwestern Canada. The region of highest wave activity seems to be related to the position of the polar vortex. We conclude that the classic approach to characterize planetary waves zonally averaged along a latitude circle is not sufficient to explain the local observations because of the strong longitudinal dependence of the wave activity.

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Zonal asymmetries in middle atmospheric ozone and water vapour derived from Odin satellite data 2001–2010

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-9865-2011 ◽

2011 ◽

Vol 11 (18) ◽

pp. 9865-9885 ◽

Cited By ~ 20

Author(s):

A. Gabriel ◽

H. Körnich ◽

S. Lossow ◽

D. H. W. Peters ◽

J. Urban ◽

...

Keyword(s):

Water Vapour ◽

Satellite Data ◽

Stationary Wave ◽

Atmospheric Ozone ◽

Mixing Processes ◽

Linear Solution ◽

Mean Values ◽

Double Peak Structure ◽

The North ◽

Wave Patterns

Abstract. Stationary wave patterns in middle atmospheric ozone (O3) and water vapour (H2O) are an important factor in the atmospheric circulation, but there is a strong gap in diagnosing and understanding their configuration and origin. Based on Odin satellite data from 2001 to 2010 we investigate the stationary wave patterns in O3 and H2O as indicated by the seasonal long-term means of the zonally asymmetric components O3* = O3-[O3] and H2O* = H2O-[H2O] ([O3], [H2O]: zonal means). At mid- and polar latitudes we find a pronounced wave one pattern in both constituents. In the Northern Hemisphere, the wave patterns increase during autumn, maintain their strength during winter and decay during spring, with maximum amplitudes of about 10–20 % of the zonal mean values. During winter, the wave one in O3* shows a maximum over the North Pacific/Aleutians and a minimum over the North Atlantic/Northern Europe and a double-peak structure with enhanced amplitude in the lower and in the upper stratosphere. The wave one in H2O* extends from the lower stratosphere to the upper mesosphere with a westward shift in phase with increasing height including a jump in phase at upper stratosphere altitudes. In the Southern Hemisphere, similar wave patterns occur mainly during southern spring. By comparing the observed wave patterns in O3* and H2O* with a linear solution of a steady-state transport equation for a zonally asymmetric tracer component we find that these wave patterns are primarily due to zonally asymmetric transport by geostrophically balanced winds, which are derived from observed temperature profiles. In addition temperature-dependent photochemistry contributes substantially to the spatial structure of the wave pattern in O3* . Further influences, e.g., zonal asymmetries in eddy mixing processes, are discussed.

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The Mechanisms that Determine the Response of the Northern Hemisphere’s Stationary Waves to North American Ice Sheets

Journal of Climate ◽

10.1175/jcli-d-18-0586.1 ◽

2019 ◽

Vol 32 (13) ◽

pp. 3917-3940 ◽

Cited By ~ 4

Author(s):

William H. G. Roberts ◽

Camille Li ◽

Paul J. Valdes

Keyword(s):

Ocean Circulation ◽

Ice Sheets ◽

Ice Sheet ◽

Stationary Wave ◽

Ocean Dynamics ◽

Stationary Waves ◽

Last Deglaciation ◽

The North ◽

Underlying Mechanisms ◽

Abrupt Shifts

Abstract Stationary waves describe the persistent meanders in the west–east flow of the extratropical atmosphere. Here, changes in stationary waves caused by ice sheets over North America are examined and the underlying mechanisms are discussed. Three experiment sets are presented showing the stationary wave response to the albedo or topography of ice sheets, as well as the albedo and topography in combination, as the forcings evolve from 21 to 6 ka. It is found that although the wintertime stationary waves have the largest amplitude, changes due to an ice sheet are equally large in summer and winter. In summer, ice sheet albedo is the dominant cause of changes: topography alone gives an opposite response to realistic ice sheets including albedo and topography. In winter, over the Atlantic, stationary wave changes are due to the ice sheet topography; over the Pacific, they are due to the persistence of summertime changes, mediated by changes in the ocean circulation. It is found that the response of stationary waves over the last deglaciation echoes the above conclusions, with no evidence of abrupt shifts in atmospheric circulation. The response linearly weakens as the albedo and height decrease from 21 to 10 ka. As potential applications, the seasonal cycle over Greenland is shown to be sensitive primarily to changes in summer climate caused by the stationary waves; the annual mean circulation over the North Pacific is found to result from summertime, albedo-forced, stationary wave effects persisting throughout the year because of ocean dynamics.

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Stationary Waves and Upward Troposphere-Stratosphere Coupling in S2S Models

10.5194/wcd-2021-58 ◽

2021 ◽

Author(s):

Chen Schwartz ◽

Chaim I. Garfinkel ◽

Priyanka Yadav ◽

Wen Chen ◽

Daniela Domeisen

Keyword(s):

North Atlantic ◽

Strong Relationship ◽

Stationary Wave ◽

Northwest Pacific ◽

Stationary Waves ◽

Western North America ◽

Model Errors ◽

The North ◽

The North Atlantic ◽

The Waves

Abstract. The simulated Northern Hemisphere stationary wave (SW) field is investigated in 11 subseasonal-to-seasonal (S2S) models. It is shown that while most models considered can well-simulate the stationary wavenumbers 1 and 2 during the first two weeks of integration, they diverge from observations following week 3. Those models with a poor resolution in the stratosphere struggle to simulate the waves, both in the troposphere and the stratosphere, even during the first two weeks, and biases extend from the troposphere all the way up to the stratosphere. Focusing on the tropospheric regions where SWs peak in amplitude reveals that the models generally do a better job in simulating the Northwest Pacific stationary trough, while certain models struggle to simulate the stationary ridges both in Western North America and the North Atlantic. In addition, a strong relationship is found between regional biases in the stationary height field and model errors in simulated upward propagation of planetary waves into the stratosphere. In the stratosphere, biases mostly are in wave-2 in those models with high stratospheric resolution, whereas in those models with low resolution in the stratosphere, a wave-1 bias is evident, which leads to a strong bias in the stratospheric mean zonal circulation due to the predominance of wave-1 there. Finally, biases in both amplitude and location of mean tropical convection and the subsequent subtropical downwelling, are identified as possible contributors to biases in the regional SW field in the troposphere.

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Instability of Northeast Siberian ice sheet during glacials

10.5194/cp-2018-79 ◽

2018 ◽

Author(s):

Zhongshi Zhang ◽

Qing Yan ◽

Elizabeth J. Farmer ◽

Camille Li ◽

Gilles Ramstein ◽

...

Keyword(s):

North America ◽

Ice Sheets ◽

Ice Sheet ◽

Stationary Wave ◽

Wave Pattern ◽

Ocean Dynamics ◽

Stationary Waves ◽

Surface Warming ◽

The North ◽

East Siberian Sea

Abstract. It has been widely believed that Northeast (NE) Siberia remained ice-free during most Pleistocene Northern Hemisphere (NH) glaciations, while ice sheets extended gradually across North America and Northwest (NW) Eurasia. However, recent fieldwork has provided robust evidence of ice sheets occupying the shallow continental shelf of the East Siberian Sea during several Pleistocene glaciations. The debate surrounding the existence and history of this enigmatic NE Siberian ice sheet highlights fundamental gaps in our current understanding of the mechanisms of glacial climate evolution. Here, we combine climate and ice sheet simulations to demonstrate how ice-vegetation-atmosphere-ocean dynamics can lead to two ice sheet configurations: the well-known Laurentide-Eurasian configuration with large ice sheets over North America and NW Eurasia, and a circum-Arctic configuration with large ice sheets over NE Siberia and the Canadian Rockies. Compared to the Laurentide-Eurasian configuration, formation of the circum-Arctic configuration can occur with an atmospheric stationary wave pattern similar to today's. Once the circum-Arctic configuration is established, it amplifies atmospheric stationary waves, leading to surface warming in the North Pacific, ablation of the NE Siberian ice sheet, and ultimately a swing to the Laurentide-Eurasian configuration. Our simulations highlight the complexity of glacial climates, and may hint towards potential mechanisms for interglacial-glacial transitions.

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Drift of large tabular icebergs in response to atmospheric surface pressure gradients, an observational study

Antarctic Science ◽

10.1017/s0954102010000027 ◽

2010 ◽

Vol 22 (2) ◽

pp. 199-208 ◽

Cited By ~ 4

Author(s):

Ian D. Turnbull

Keyword(s):

Surface Pressure ◽

Ocean Current ◽

Pressure Gradients ◽

Limited Region ◽

North West ◽

The North ◽

Global Positioning ◽

Parking Lot ◽

Pressure Anomaly ◽

Pressure Regime

AbstractWhile ocean current and winds certainly play a major role in guiding the trajectories of free-floating icebergs, the direct effect of atmospheric surface pressure gradients can also have an important influence on the trajectories of large icebergs whose horizontal dimensions are sufficiently great to span synoptic systems. This effect is examined as a way of understanding why icebergs B15A, B15J, B15K, and C16 became “trapped” in a limited region immediately north of Ross Island for a period of several years, without being grounded. This limited region is otherwise flushed annually by summer surface winds and currents; thus the delay of the northward drift of the large icebergs (particularly B15A and B15J) defied expectation. The best explanation for this unexpected iceberg behaviour is that the large volcanic massifs on Ross Island create a quasi-permanent surface pressure anomaly patterned as a dipole, with high pressure in the area upwind of the island (an area appropriately called Windless Bight), and low pressure in the downwind area of the iceberg parking lot. The surface pressure regime experienced by two icebergs B15A and B15K is estimated using Automatic Weather Station observations and Global Positioning System receivers deployed on their surfaces to explain why they remained trapped. Breakdown of the atmospheric pressure gradients allowed them to eventually escape from the region to the north-west.

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Quasi-stationary planetary waves in late winter Antarctic stratosphere temperature as a possible indicator of spring total ozone

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-28945-2011 ◽

2011 ◽

Vol 11 (10) ◽

pp. 28945-28967

Author(s):

V. O. Kravchenko ◽

O. M. Evtushevsky ◽

A. V. Grytsai ◽

A. R. Klekociuk ◽

G. P. Milinevsky ◽

...

Keyword(s):

Total Ozone ◽

Large Scale ◽

Stationary Wave ◽

Planetary Waves ◽

Ozone Hole ◽

Late Winter ◽

Stationary Waves ◽

Wave Effects ◽

Antarctic Ozone ◽

Highly Correlated

Abstract. Stratospheric preconditions for the annual Antarctic ozone hole are analysed using the amplitude of quasi-stationary planetary waves in temperature as a predictor of total ozone column behaviour. It is found that the quasi-stationary wave amplitude in August is highly correlated with September–November total ozone over Antarctica with correlation coefficient as high as 0.83 indicating that quasi-stationary wave effects in late winter have a persisting influence on the evolution of the ozone hole during the following three months. Correlation maxima are found in both the lower and middle stratosphere. They are likely manifestations of wave activity influence on chemical ozone depletion and large-scale ozone transport, respectively. Both correlation maxima indicate that spring total ozone tends to increase in the case of amplified activity of quasi-stationary waves in late winter.

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