scholarly journals Modulation of northern hemisphere wintertime stationary planetary wave activity: East Asian climate relationships by the Quasi-Biennial Oscillation

2007 ◽  
Vol 112 (D20) ◽  
Author(s):  
Wen Chen ◽  
Tim Li
Keyword(s):  
Northern Hemisphere ◽  
Planetary Wave ◽  
East Asian ◽  
Wave Activity ◽  
Quasi Biennial Oscillation ◽  
East Asian Climate ◽  
Stationary Planetary Wave ◽  
Biennial Oscillation

scholarly journals On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/2016

2018 ◽  
Vol 18 (7) ◽  
pp. 4803-4815 ◽  
Author(s):  
Vivien Matthias ◽  
Manfred Ern
Keyword(s):  
Planetary Wave ◽  
Polar Night ◽  
Quasi Biennial Oscillation ◽  
Model Studies ◽  
Broadband Emission ◽  
Variable Gravity ◽  
Stationary Planetary Wave ◽  
Second Period ◽  
Biennial Oscillation

Abstract. The midwinter 2015/2016 was characterized by an unusually strong polar night jet (PNJ) and extraordinarily large stationary planetary wave (SPW) amplitudes in the subtropical mesosphere. The aim of this study is, therefore, to find the origin of these mesospheric SPWs in the midwinter 2015/2016 study period. The study duration is split into two periods: the first period runs from late December 2015 until early January 2016 (Period I), and the second period from early January until mid-January 2016 (Period II). While the SPW 1 dominates in the subtropical mesosphere in Period I, it is the SPW 2 that dominates in Period II. There are three possibilities explaining how SPWs can occur in the mesosphere: (1) they propagate upward from the stratosphere, (2) they are generated in situ by longitudinally variable gravity wave (GW) drag, or (3) they are generated in situ by barotropic and/or baroclinic instabilities. Using global satellite observations from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) the origin of the mesospheric SPWs is investigated for both time periods. We find that due to the strong PNJ the SPWs were not able to propagate upward into the mesosphere northward of 50∘ N but were deflected upward and equatorward into the subtropical mesosphere. We show that the SPWs observed in the subtropical mesosphere are the same SPWs as in the mid-latitudinal stratosphere. Simultaneously, we find evidence that the mesospheric SPWs in polar latitudes were generated in situ by longitudinally variable GW drag and that there is a mixture of in situ generation by longitudinally variable GW drag and by instabilities at mid-latitudes. Our results, based on observations, show that the abovementioned three mechanisms can act at the same time which confirms earlier model studies. Additionally, the possible contribution from, or impact of, unusually strong SPWs in the subtropical mesosphere to the disruption of the quasi-biennial oscillation (QBO) in the same winter is discussed.

scholarly journals The role of the QBO in the inter-hemispheric coupling of summer mesospheric temperatures

2010 ◽  
Vol 10 (10) ◽  
pp. 23403-23422
Author(s):  
P. J. Espy ◽  
S. Ochoa Fernández ◽  
P. Forkman ◽  
D. Murtagh ◽  
J. Stegman
Keyword(s):  
Time Series ◽  
Planetary Wave ◽  
Wave Activity ◽  
Quasi Biennial Oscillation ◽  
Mesospheric Temperature ◽  
Stratospheric Dynamics ◽  
Time Lagged ◽  
Biennial Oscillation ◽  
Lagged Correlation

Abstract. Inter-hemispheric coupling between the polar summer mesosphere and planetary-wave activity in the extra-tropical winter stratosphere has recently been inferred using Polar Mesospheric Cloud (PMC) properties as a proxy for mesospheric temperature (Karlsson et al., 2007). Here we confirm these results using a ten-year time series of July mesospheric temperatures near 60° N derived from the hydroxyl (OH) nightglow. In addition, we show that the time/lagged correlation between these summer mesospheric temperatures and the ECMWF winter stratospheric temperatures displays a strong Quasi-Biennial Oscillation (QBO). The sign and phase of the correlation is consistent with the QBO modulation of the extra-tropical stratospheric dynamics in the Southern Hemisphere via the Holton-Tan mechanism (Holton and Tan, 1980). This lends strength to the identification of synoptic and planetary waves as the driver of the inter-hemispheric coupling, and results in a strong QBO modulation of the polar summer mesospheric temperatures.

Interdecadal Variations of the East Asian Winter Monsoon and Their Association with Quasi-Stationary Planetary Wave Activity

2009 ◽  
Vol 22 (18) ◽  
pp. 4860-4872 ◽  
Author(s):  
Lin Wang ◽  
Ronghui Huang ◽  
Lei Gu ◽  
Wen Chen ◽  
Lihua Kang
Keyword(s):  
Planetary Wave ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Wave Activity ◽  
Winter Monsoon ◽  
Planetary Waves ◽  
Asian Winter Monsoon ◽  
Zonal Wavenumber ◽  
Propagation Of Waves ◽  
Stationary Planetary Wave

Abstract Interdecadal variations of the East Asian winter monsoon (EAWM) and their association with the quasi-stationary planetary wave activity are analyzed by using the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis dataset and the National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis dataset. It is found that the EAWM experienced a significant weakening around the late 1980s; that is, the EAWM was strong during 1976–87 and became weak after 1988. This leads to an obvious increase in the wintertime surface air temperature as well as a decrease in the frequency of occurrence of cold waves over East Asia. The dynamical process through which the EAWM is weakened is investigated from the perspective of quasi-stationary planetary waves. It is found that both the propagation and amplitude of quasi-stationary planetary waves have experienced obvious interdecadal variations, which are well related to those of the EAWM. Compared to the period 1976–87, the horizontal propagation of quasi-stationary planetary waves after 1988 is enhanced along the low-latitude waveguide in the troposphere, and the upward propagation of waves into the stratosphere is reduced along the polar waveguide. This results in a weakened subtropical jet around 40°N due to the convergence of the Eliassen–Palm flux. The East Asian jet stream is then weakened, leading to the weakening of the EAWM since 1988. In addition, the amplitude of quasi-stationary planetary waves is significantly weakened around 45°N, which is related to the reduced upward propagation of waves from the lower boundary after 1988. This reduced amplitude may weaken both the Siberian high and the Aleutian low, reduce the pressure gradient in between, and then weaken the EAWM. Further analyses indicate that zonal wavenumber 2 plays the dominant role in this process.

scholarly journals The role of the QBO in the inter-hemispheric coupling of summer mesospheric temperatures

2011 ◽  
Vol 11 (2) ◽  
pp. 495-502 ◽  
Author(s):  
P. J. Espy ◽  
S. Ochoa Fernández ◽  
P. Forkman ◽  
D. Murtagh ◽  
J. Stegman
Keyword(s):  
Time Series ◽  
Planetary Wave ◽  
Wave Activity ◽  
Quasi Biennial Oscillation ◽  
Mesospheric Temperature ◽  
Stratospheric Dynamics ◽  
Time Lagged ◽  
Biennial Oscillation ◽  
Lagged Correlation

Abstract. Inter-hemispheric coupling between the polar summer mesosphere and planetary-wave activity in the extra-tropical winter stratosphere has recently been inferred using Polar Mesospheric Cloud (PMC) properties as a proxy for mesospheric temperature (Karlsson et al., 2007). Here we confirm these results using a ten-year time series of July mesospheric temperatures near 60° N derived from the hydroxyl (OH) nightglow. In addition, we show that the time-lagged correlation between these summer mesospheric temperatures and the ECMWF winter stratospheric temperatures displays a strong Quasi-Biennial Oscillation (QBO). The sign and phase of the correlation is consistent with the QBO modulation of the extra-tropical stratospheric dynamics in the Southern Hemisphere via the Holton-Tan mechanism (Holton and Tan, 1980). This lends strength to the identification of synoptic and planetary waves as the driver of the inter-hemispheric coupling, and results in a strong QBO modulation of the polar summer mesospheric temperatures.

scholarly journals The Arctic vortex in March 2011: a dynamical perspective

2011 ◽  
Vol 11 (22) ◽  
pp. 11447-11453 ◽  
Author(s):  
M. M. Hurwitz ◽  
P. A. Newman ◽  
C. I. Garfinkel
Keyword(s):  
Planetary Wave ◽  
La Niña ◽  
The Arctic ◽  
Late Winter ◽  
Quasi Biennial Oscillation ◽  
The North ◽  
La Nina ◽  
Sea Surface Temperature Anomalies ◽  
Biennial Oscillation ◽  
The North Pacific

Abstract. Despite the record ozone loss observed in March 2011, dynamical conditions in the Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving in February preceded cold anomalies in the polar lower stratosphere in March and a relatively late breakup of the Arctic vortex in April. La Niña conditions and the westerly phase of the quasi-biennial oscillation (QBO) were observed in March 2011. Though these conditions are generally associated with a stronger vortex in mid-winter, the respective cold anomalies do not persist through March. Therefore, the La Niña and QBO-westerly conditions cannot explain the observed cold anomalies in March 2011. In contrast, positive sea surface temperature anomalies in the North Pacific may have contributed to the unusually weak tropospheric wave driving and strong Arctic vortex in late winter 2011.

Comparison of Key Characteristics of Remarkable SSW Events in the Southern and Northern Hemisphere

2021 ◽  
Author(s):  
Michal Kozubek ◽  
Peter Krizan
Keyword(s):  
Northern Hemisphere ◽  
Planetary Wave ◽  
Polar Vortex ◽  
Wave Number ◽  
Strong Activity ◽  
Key Characteristics ◽  
Zonal Wave Number ◽  
Show Difference ◽  
Temperature Enhancement ◽  
Stationary Planetary Wave

<p>An exceptionally strong sudden stratospheric warming (SSW) in the Southern Hemisphere (SH) during September 2019 was observed. Because SSW in the SH is very rare, comparison with the only recorded major SH SSW is done. According to World Meteorological Organization (WMO) definition, the SSW in 2019 has to be classified as minor. The cause of SSW in 2002 was very strong activity of stationary planetary wave with zonal wave-number (ZW) 2, which reached its maximum when the polar vortex split into two circulations with polar temperature enhancement by 30 K/week and it penetrated deeply to the lower stratosphere and upper troposphere. On the other hand, the minor SSW in 2019 involved an exceptionally strong wave-1 planetary wave and a large polar temperature enhancement by 50.8 K/week, but it affected mainly the middle and upper stratosphere. The strongest SSW in the Northern Hemisphere was observed in 2009. This study provides comparison of two strongest SSW in the SH and the strongest SSW in the NH to show difference between two hemispheres and possible impact to the lower or higher layers.</p>

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