Solar-related and terrestrial drivers modulating the northern polar vortex

2021 ◽  
Author(s):  
Antti Salminen ◽  
Timo Asikainen ◽  
Ville Maliniemi ◽  
Kalevi Mursula
Keyword(s):  
Solar Radiation ◽  
Southern Oscillation ◽  
Energetic Electron ◽  
Sunspot Cycle ◽  
Polar Vortex ◽  
Multilinear Regression ◽  
Quasi Biennial Oscillation ◽  
Multilinear Regression Analysis ◽  
Volcanic Aerosols ◽  
Energetic Particle Precipitation

<p>The wintertime stratosphere is dominated by the polar vortex, a strong westerly wind, which surrounds the cold polar region. In the northern hemisphere the polar vortex can vary a lot during the winter and these variations affect the surface weather, e.g., in Europe and North America. Earlier studies have shown that the northern polar vortex is modulated by different terrestrial drivers and two solar-related drivers: electromagnetic radiation and energetic particle precipitation. Solar radiation varies in concert with the sunspot cycle by affecting the upper atmosphere at lower latitudes. Energetic electron precipitation (EEP) is driven by the solar wind and affects the polar stratosphere and mesosphere by forming ozone depleting NOx and HOx compounds. However, it is unclear how the effects of these solar-related and other, terrestrial drivers compare to each other. In this study we examine the effects of two solar-related drivers (solar radiation and EEP) and three terrestrial drivers (Quasi-Biennial Oscillation (QBO), El-Nino Southern Oscillation (ENSO) and volcanic aerosols) on the northern polar vortex. We use a new composite dataset including ERA-40 and ERA-Interim reanalysis of atmospheric variables and the multilinear regression analysis to estimate atmospheric responses to these five drivers in years 1957 – 2017. We confirm the findings of earlier studies that westerly QBO wind, cold ENSO, volcanic aerosols and increased EEP are associated with a stronger polar vortex. Furthermore, we find that EEP produces the strongest and most significant effect on the northern polar vortex among the studied variables. Only in December the effect of QBO is comparable to the EEP effect. We also find that EEP effect is strong and significant in the easterly QBO phase, while in the westerly phase it does not stand out from the effects of other drivers.</p>

scholarly journals Comparing the effects of solar-related and terrestrial drivers on the northern polar vortex

2020 ◽  
Vol 10 ◽  
pp. 56
Author(s):  
Antti Salminen ◽  
Timo Asikainen ◽  
Ville Maliniemi ◽  
Kalevi Mursula
Keyword(s):  
Solar Irradiance ◽  
Southern Oscillation ◽  
Energetic Electron ◽  
Polar Vortex ◽  
Multilinear Regression ◽  
Quasi Biennial Oscillation ◽  
Linear Effect ◽  
Multilinear Regression Analysis ◽  
Volcanic Aerosols ◽  
Almost All

Northern polar vortex experiences significant variability during Arctic winter. Solar activity contributes to this variability via solar irradiance and energetic particle precipitation. Recent studies have found that energetic electron precipitation (EEP) affects the polar vortex by forming ozone depleting NOx compounds. However, it is still unknown how the EEP effect compares to variabilities caused by, e.g., solar irradiance or terrestrial drivers. In this study we examine the effects of EEP, solar irradiance, El-Niño-Southern Oscillation (ENSO), volcanic aerosols and quasi-biennial oscillation (QBO) on the northern wintertime atmosphere. We use geomagnetic Ap-index to quantify EEP activity, sunspot numbers to quantify solar irradiance, Niño 3.4 index for ENSO and aerosol optical depth for the amount of volcanic aerosols. We use a new composite dataset including ERA-40 and ERA-Interim reanalysis of zonal wind and temperature and multilinear regression analysis to estimate atmospheric responses to the above mentioned explaining variables in winter months of 1957–2017. We confirm the earlier results showing that EEP and QBO strengthen the polar vortex. We find here that the EEP effect on polar vortex is stronger and more significant than the effects of the other drivers in almost all winter months in most conditions. During 1957–2017 the considered drivers together explain about 25–35% of polar vortex variability while the EEP effect alone explains about 10–20% of it. Thus, a major part of variability is not due to the linear effect by the studied explaining variables. The positive EEP effect is particularly strong if QBO-wind at 30 hPa has been easterly during the preceding summer, while for a westerly QBO the EEP effect is weaker and less significant.

Solar-related and internal drivers of the northern polar vortex

2020 ◽  
Author(s):  
Antti Salminen ◽  
Timo Asikainen ◽  
Ville Maliniemi ◽  
Kalevi Mursula
Keyword(s):  
Southern Oscillation ◽  
Linear Regression Analysis ◽  
Energetic Electron ◽  
Polar Vortex ◽  
Analysis Data ◽  
Multiple Linear Regression Analysis ◽  
Internal Factors ◽  
Quasi Biennial Oscillation ◽  
Low Latitudes ◽  
Volcanic Aerosols

<p>During the winter, a polar vortex, a strong westerly thermal wind, forms in the polar stratosphere. In the northern hemisphere the polar vortex varies significantly during and between winters. The Sun and the solar wind affect the polar vortex via two separate factors: electromagnetic radiation and energetic particle precipitation. Earlier studies have shown that increased energetic electron precipitation (EEP) decreases ozone in the polar upper atmosphere and strengthens the northern polar vortex, while solar irradiance affects temperature and ozone in the stratosphere directly at low latitudes and indirectly at high latitudes. In addition to the solar-related drivers, the northern polar vortex is also affected by different atmospheric internal factors such as Quasi-Biennial Oscillation (QBO), El-Nino Southern Oscillation (ENSO) and volcanic aerosols. Several studies have shown that the QBO modulates the effects that the solar-related drivers and ENSO cause to the polar vortex. In this study we examine and compare effects of the two solar-related drivers (solar radiation and EEP) and three atmospheric internal factors (QBO, ENSO and volcanic aerosols) on the polar vortex. We use multiple linear regression analysis to estimate the effects of each factor on temperature and zonal wind. We concentrate on the northern wintertime stratosphere and troposphere and examine the period of 1957-2017 using a combination of ERA-40 and ERA-Interim re-analysis data. We also study these effects separately in the two QBO phases. While we confirm that increased EEP is associated with a strengthened polar vortex, in accordance with the earlier studies, we further show that EEP is the largest and most significant factor among those studied affecting  the northern polar vortex variability. We also find that the EEP effect on polar vortex is particularly strong in the easterly phase of QBO while in the westerly phase the EEP effect is weakened and does not stand out from other effects.</p>

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).

Impact of the Quasi-Biennial Oscillation on the boreal winter tropospheric circulation in CMIP5/6 models

2020 ◽  
Author(s):  
Jian Rao ◽  
Chaim Garfinkel ◽  
Ian White ◽  
Chen Schwartz
Keyword(s):  
Pacific Ocean ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Buoyancy Frequency ◽  
Maritime Continent ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Enso Events ◽  
The Pacific ◽  
Biennial Oscillation

<p>Using 17 CMIP5/6 models with a spontaneously-generated quasi-biennial oscillation (QBO)-like phenomenon, this study explores and evaluates three dynamical pathways for impacts of the QBO on the troposphere: (i) the Holtan-Tan (HT) effect on the stratospheric polar vortex and the northern annular mode (NAM), (ii) the subtropical zonal wind downward arching over the Pacific, and (iii) changes in local convection over the Maritime Continent and Indo-Pacific Ocean. More than half of the models can reproduce at least one of the three pathways, but few models can reproduce all of the three routes. Firstly, most models are able to simulate a weakened polar vortex during easterly QBO (EQBO) winters, in agreement with the observed HT effect. However, the weakened polar vortex response during EQBO winters is underestimated or not present at all in other models, and hence the QBO → vortex → tropospheric NAM/AO chain is not simulated. For the second pathway associated with the downward arching of the QBO winds, seven models incorrectly or poorly simulate the extratropical easterly anomaly center over 20–40°N in the Pacific sector during EQBO, and hence the negative relative vorticity anomalies poleward of the easterly center is not resolved in those models, leading to an underestimated or incorrectly modelled height response over North Pacific. However the other ten do capture this effect. The third pathway is only observed in the Indo-Pacific Ocean, where the strong climatological deep convection and the warm pool are situated. Nine models can simulate the convection anomalies associated with the QBO over the Maritime Continent, which is likely caused by the near-tropopause low buoyancy frequency anomalies. No robust relationship between the QBO and El Niño–Southern Oscillation (ENSO) events can be established using the ERA-Interim reanalysis, and nine models consistently confirm little modulation of the ocean basin-wide Walker circulation and ENSO events by the QBO.</p>

scholarly journals Characteristics of tropopause parameters as observed with GPS radio occultation

2014 ◽  
Vol 7 (11) ◽  
pp. 3947-3958 ◽  
Author(s):  
T. Rieckh ◽  
B. Scherllin-Pirscher ◽  
F. Ladstädter ◽  
U. Foelsche
Keyword(s):  
Annual Cycle ◽  
Radio Occultation ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Lapse Rate ◽  
Quasi Biennial Oscillation ◽  
Gps Radio Occultation ◽  
Statistical Measures ◽  
The Mean ◽  
Individual Profiles

Abstract. Characteristics of the lapse rate tropopause are analyzed globally for tropopause altitude and temperature using global positioning system (GPS) radio occultation (RO) data from late 2001 to the end of 2013. RO profiles feature high vertical resolution and excellent quality in the upper troposphere and lower stratosphere, which are key factors for tropopause determination, including multiple ones. RO data provide measurements globally and allow examination of both temporal and spatial tropopause characteristics based entirely on observational measurements. To investigate latitudinal and longitudinal tropopause characteristics, the mean annual cycle, and inter-annual variability, we use tropopauses from individual profiles as well as their statistical measures for zonal bands and 5° × 10° bins. The latitudinal structure of first tropopauses shows the well-known distribution with high (cold) tropical tropopauses and low (warm) extra-tropical tropopauses. In the transition zones (20 to 40° N/S), individual profiles reveal varying tropopause altitudes from less than 7 km to more than 17 km due to variability in the subtropical tropopause break. In this region, we also find multiple tropopauses throughout the year. Longitudinal variability is strongest at northern hemispheric mid latitudes and in the Asian monsoon region. The mean annual cycle features changes in amplitude and phase, depending on latitude. This is caused by different underlying physical processes (such as the Brewer–Dobson circulation – BDC) and atmospheric dynamics (such as the strong polar vortex in the southern hemispheric winter). Inter-annual anomalies of tropopause parameters show signatures of El Niño–Southern Oscillation (ENSO), the quasi–biennial oscillation (QBO), and the varying strength of the polar vortex, including sudden stratospheric warming (SSW) events. These results are in good agreement with previous studies and underpin the high utility of the entire RO record for investigating latitudinal, longitudinal, and temporal tropopause characteristics globally.

scholarly journals Evidence for energetic particle precipitation and quasi-biennial oscillation modulations of the Antarctic NO<sub>2</sub> springtime stratospheric column from OMI observations

2020 ◽  
Vol 20 (11) ◽  
pp. 6259-6271
Author(s):  
Emily M. Gordon ◽  
Annika Seppälä ◽  
Johanna Tamminen
Keyword(s):  
Energetic Particle ◽  
Activity Index ◽  
Polar Vortex ◽  
Late Winter ◽  
Ozone Monitoring Instrument ◽  
Particle Precipitation ◽  
Quasi Biennial Oscillation ◽  
Energetic Particle Precipitation ◽  
The Antarctic ◽  
Biennial Oscillation

Abstract. Observations from the Ozone Monitoring Instrument (OMI) on the Aura satellite are used to study the effect of energetic particle precipitation (EPP, as proxied by the geomagnetic activity index, Ap) on the Antarctic stratospheric NO2 column in late winter–spring (August–December) during the period from 2005 to 2017. We show that the polar (60–90∘ S) stratospheric NO2 column is significantly correlated with EPP throughout the Antarctic spring, until the breakdown of the polar vortex in November. The strongest correlation takes place during years with the easterly phase of the quasi-biennial oscillation (QBO). The QBO modulation may be a combination of different effects: the QBO is known to influence the amount of the primary NOx source (N2O) via transport from the Equator to the polar region; and the QBO phase also affects polar temperatures, which may provide a link to the amount of denitrification occurring in the polar vortex. We find some support for the latter in an analysis of temperature and HNO3 observations from the Microwave Limb Sounder (MLS, on Aura). Our results suggest that once the background effect of the QBO is accounted for, the NOx produced by EPP significantly contributes to the stratospheric NO2 column at the time and altitudes when the ozone hole is present in the Antarctic stratosphere. Based on our findings, and the known role of NOx as a catalyst for ozone loss, we propose that as chlorine activation continues to decrease in the Antarctic stratosphere, the total EPP-NOx needs be accounted for in predictions of Antarctic ozone recovery.

scholarly journals Characteristics of tropopause parameters as observed with GPS radio occultation

2014 ◽  
Vol 7 (5) ◽  
pp. 4693-4727 ◽  
Author(s):  
T. Rieckh ◽  
B. Scherllin-Pirscher ◽  
F. Ladstädter ◽  
U. Foelsche
Keyword(s):  
Annual Cycle ◽  
Radio Occultation ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Lapse Rate ◽  
Monthly Basis ◽  
Quasi Biennial Oscillation ◽  
Gps Radio Occultation ◽  
The Mean ◽  
Individual Profiles

Abstract. Characteristics of the lapse rate tropopause are analyzed globally for tropopause altitude and temperature using Global Positioning System (GPS) Radio Occultation (RO) data from late 2001 to 2012. RO profiles feature high vertical resolution and excellent quality in the upper troposphere and lower stratosphere, which are key factors for tropopause determination, including multiple ones. Furthermore, global coverage is reached on a monthly basis, allowing to examine both temporal and spatial characteristics thoroughly. To investigate latitudinal and longitudinal tropopause characteristics, the mean annual cycle, and inter-annual variability, we use tropopauses from individual profiles as well as their monthly mean and median for 10° zonal bands. The latitudinal structure of first tropopauses shows the well-known distribution with high (cold) tropical tropopauses and low (warm) extratropical tropopauses. In the transition zones (20° N/S to 40° N/S), individual profiles reveal varying tropopause altitudes from 7 km to 17 km due to the influence of the subtropical jets. In this region, we also find multiple tropopauses throughout the year. Longitudinal variability is strongest at northern hemispheric mid latitudes and in the Asian monsoon region. The mean annual cycle features changes in amplitude and phase depending on latitude. This is caused by different underlying physical processes (such as the Brewer-Dobson Circulation) and atmospheric dynamics (such as the very strong polar vortex in southern hemispheric winter). Inter-annual anomalies of tropopause parameters show signatures of El Niño–Southern Oscillation, the Quasi-Biennial Oscillation, and the varying strength of the polar vortex, including sudden stratospheric warming events.

scholarly journals Global distribution of total ozone and lower stratospheric temperature variations

2003 ◽  
Vol 3 (4) ◽  
pp. 3411-3449 ◽  
Author(s):  
W. Steinbrecht ◽  
B. Hassler ◽  
H. Claude ◽  
P. Winkler ◽  
R. S. Stolarski
Keyword(s):  
Solar Cycle ◽  
Total Ozone ◽  
Southern Oscillation ◽  
Linear Trend ◽  
Polar Vortex ◽  
High Latitudes ◽  
Least Squares Regression ◽  
Quasi Biennial Oscillation ◽  
Vortex Strength ◽  
Low Latitudes

Abstract. This study gives an overview of interannual variations of total ozone and 50hPa temperature. It is based on newer and longer records from the 1979 to 2001 Total Ozone Monitoring Spectrometer (TOMS) and Solar Backscatter Ultraviolet (SBUV) instruments, and on US National Center for Environmental Prediction (NCEP) reanalyses. Multiple linear least squares regression is used to quantify various natural and anthropogenic influences. For most influences the total ozone and 50hPa temperature responses look very similar, reflecting a very close coupling. As a rule of thumb, a 10 Dobson Unit (DU) change in total ozone corresponds to a 1K change of 50hPa temperature. Large influences come from the linear trend term, up to −30 DU or −1.5 K/decade, from terms related to polar vortex strength, up to 50 DU or 5 K (typical, minimum to maximum), from tropospheric meteorology, up to 30 DU or 3 K, or from the Quasi-Biennial Oscillation (QBO), up to 25 DU or 2.5 K. The 11-year solar cycle, up to 25 DU or 2.5 K, El Niño/Southern Oscillation (ENSO), up to 10 DU or 1 K, are somewhat smaller influences. Stratospheric aerosol after the 1991 Pinatubo eruption lead to warming up to 3 K at low latitudes and to ozone depletion up to 40 DU at high latitudes. Response to QBO, polar vortex strength, and to a lesser degree to ENSO, exhibit an inverse correlation between low latitudes and higher latitudes. Responses to the solar cycle or 400 hPa temperature, however, have the same sign over most of the globe. Responses are usually zonally symmetric at low and mid-latitudes, but asymmetric at high latitudes. There, solar cycle, QBO or ENSO influence position and strength of the stratospheric anti-cyclones over the Aleutians and south of Australia.

scholarly journals Evolution of the stratospheric polar vortex in the Southern and Northern Hemispheres over the period 1979 – 2020

2021 ◽  
Author(s):  
Audrey Lecouffe ◽  
Sophie Godin-Beekmann ◽  
Andrea Pazmiño ◽  
Alain Hauchecorne
Keyword(s):  
Southern Hemisphere ◽  
Potential Vorticity ◽  
Southern Oscillation ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Geophysical Research ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Antarctic Polar Vortex ◽  
The Antarctic

&lt;p&gt;The stratospheric polar vortex in the Southern Hemisphere plays an important role in the intensity of the stratospheric ozone destruction during austral spring, which started in the late 1970s. The so-called ozone hole has in turn influenced the evolution of weather patterns in the Southern Hemisphere in the last decades (WMO, 2018). The Northern Hemisphere polar vortex is less stable because of larger dynamical activity in winter. It is thus less cold and polar arctic ozone losses are less important. The seasonal and interannual evolution of the polar vortex in both hemispheres has been analyzed using meteorological fields from the European Center for Meteorology Weather Forecasts ERA-Interim reanalyses and the MIMOSA model (Mod&amp;#233;lisation Isentrope du transport M&amp;#233;so-&amp;#233;chelle de l&amp;#8217;Ozone Stratosph&amp;#233;rique par Advection, Hauchecorne et al., 2002). This model provides high spatial resolution potential vorticity (PV) and equivalent latitude fields at several isentropic levels (675K, 550K and 475K) that are used to evaluate the temporal evolution of the polar vortex edge. The edge of the vortex is computed on isentropic surfaces from the wind and gradient of PV as a function of equivalent latitude (e.g. Nash et al, 1996; Godin et al., 2001). On an interannual scale, the signature of some typical forcings driving stratospheric natural variability such as the 11-year solar cycle, the quasi-biennial oscillation (QBO), and El Ni&amp;#241;o Southern Oscillation (ENSO) is evaluated. The study includes analysis of the onset and breakup dates of the polar vortex, which are determined from the wind field along the vortex edge. Several threshold values, such as 15.2m/s, 20m/s and 25m/s following Akiyoshi et al. (2009) are used. Results on the seasonal and interannual evolution of the intensity and position of the vortex edge, as well as the onset and breakup dates of the Southern and Northern polar vortex edge over the 1979 &amp;#8211; 2020 period will be shown.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;ul&gt;&lt;li&gt;Akiyoshi, H., Zhou, L., Yamashita, Y., Sakamoto, K., Yoshiki, M., Nagashima, T., Takahashi, M., Kurokawa, J., Takigawa, M., and Imamura, T. A CCM simulation of the breakup of the Antarctic polar vortex in the years 1980&amp;#8211;2004 under the CCMVal scenarios, Journal ofGeophysical Research: Atmospheres, 114, 2009.&lt;/li&gt; &lt;li&gt;Godin S., V. Bergeret, S. Bekki, C. David, G. Me&amp;#769;gie, Study of the interannual ozone loss and the permeability of the Antarctic Polar Vortex from long-term aerosol and ozone lidar measurements in Dumont d&amp;#8217;Urville (66.4&amp;#9702;S, 140&amp;#9702;E), J. Geophys. Res., 106, 1311-1330, 2001.&lt;/li&gt; &lt;li&gt;Hauchecorne, A., S. Godin, M. Marchand, B. Hesse, and C. Souprayen, Quantification of the transport of chemical constituents from the polar vortex to midlatitudes in the lower stratosphere using the high-resolution advection model MIMOSA and effective diffusivity, J. Geophys. Res., 107 (D20), 8289, doi:10.1029/2001JD000491, 2002.&lt;/li&gt; &lt;li&gt;Nash, E. R., Newman, P. A., Rosenfield, J. E., and Schoeberl, M. R. (1996), An objective determination of the polar vortex using Ertel&amp;#8217;s potential vorticity, Journal of geophysical research, VOL.101(D5), 9471- 9478&lt;/li&gt; &lt;li&gt;World Meteorological Organization, Global Ozone Research and Monitoring Project &amp;#8211; Report No. 58, 2018.&lt;/li&gt; &lt;/ul&gt;

Sign in / Sign up

Export Citation Format

Share Document