scholarly journals Baroclinic Instability in High Latitudes Induced by Polar Vortex: A Connection to the Arctic Oscillation

2002 ◽  
Vol 59 (1) ◽  
pp. 69-82 ◽  
Author(s):  
H. L. Tanaka ◽  
Hiroki Tokinaga
Keyword(s):  
Arctic Oscillation ◽  
Baroclinic Instability ◽  
Polar Vortex ◽  
The Arctic ◽  
High Latitudes ◽  
The Arctic Oscillation

scholarly journals Volcanic activity sparks the Arctic Oscillation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weizheng Qu ◽  
Fei Huang ◽  
Jinping Zhao ◽  
Ling Du ◽  
Yong Cao
Keyword(s):  
Volcanic Activity ◽  
Volcanic Eruption ◽  
Arctic Oscillation ◽  
Polar Vortex ◽  
Volcanic Eruptions ◽  
The Arctic ◽  
Vortex System ◽  
Significant Fluctuation ◽  
The Arctic Oscillation

AbstractThe parasol effect of volcanic dust and aerosol caused by volcanic eruption results in the deepening and strengthening of the Arctic vortex system, thus stimulating or strengthening the Arctic Oscillation (AO). Three of the strongest AOs in more than a century have been linked to volcanic eruptions. Every significant fluctuation of the AO index (AOI = ΔH_middle latitudes − ΔH_Arctic) for many years has been associated with a volcanic eruption. Volcanic activity occurring at different locations in the Arctic vortex circulation will exert different effects on the polar vortex.

Improvement in Prediction of the Arctic Oscillation with a Realistic Ocean Initial Condition in a CGCM

2015 ◽  
Vol 28 (22) ◽  
pp. 8951-8967 ◽  
Author(s):  
Hae-Jeong Kim ◽  
Joong-Bae Ahn
Keyword(s):  
Arctic Oscillation ◽  
Polar Vortex ◽  
Polar Front ◽  
Forecast Skill ◽  
Sea Surface ◽  
The Arctic ◽  
Initial Condition ◽  
Stratospheric Polar Vortex ◽  
The Arctic Oscillation ◽  
Polar Front Jet

Abstract This study verifies the impact of improved ocean initial conditions on the Arctic Oscillation (AO) forecast skill by assessing the one-month lead predictability of boreal winter AO using the Pusan National University (PNU) coupled general circulation model (CGCM). Hindcast experiments were performed on two versions of the model, one does not use assimilated ocean initial data (V1.0) and one does (V1.1), and the results were comparatively analyzed. The forecast skill of V1.1 was superior to that of V1.0 in terms of the correlation coefficient between the predicted and observed AO indices. In the regression analysis, V1.1 showed more realistic spatial similarities than V1.0 did in predicted sea surface temperature and atmospheric circulation fields. The authors suggest the relative importance of the contribution of the ocean initial condition to the AO forecast skill was because the ocean data assimilation increased the predictability of the AO, to some extent, through the improved interaction between tropical forcing induced by realistic sea surface temperature (SST) and atmospheric circulation. In V1.1, as in the observation, the cold equatorial Pacific SST anomalies generated the weakened tropical convection and Hadley circulation over the Pacific, resulting in a decelerated subtropical jet and accelerated polar front jet in the extratropics. The intensified polar front jet implies a stronger stratospheric polar vortex relevant to the positive AO phase; hence, surface manifestations of the reflected positive AO phase were then induced through the downward propagation of the stratospheric polar vortex. The results suggest that properly assimilated initial ocean conditions might contribute to improve the predictability of global oscillations, such as the AO, through large-scale tropical ocean–atmosphere interaction.

scholarly journals A strong phase reversal of the Arctic Oscillation in midwinter 2015/2016: Role of the stratospheric polar vortex and tropospheric blocking

2016 ◽  
Vol 121 (22) ◽  
pp. 13,443-13,457 ◽  
Author(s):  
Hoffman H. N. Cheung ◽  
Wen Zhou ◽  
Marco Y. T. Leung ◽  
C. M. Shun ◽  
S. M. Lee ◽  
...  
Keyword(s):  
Arctic Oscillation ◽  
Polar Vortex ◽  
The Arctic ◽  
Stratospheric Polar Vortex ◽  
Strong Phase ◽  
Phase Reversal ◽  
The Arctic Oscillation

The Impact of the Stratospheric Polar Vortex Shift on the Arctic Oscillation

2021 ◽  
Vol 34 (10) ◽  
pp. 4129-4143
Author(s):  
Yongjia Lu ◽  
Wenshou Tian ◽  
Jiankai Zhang ◽  
Jinlong Huang ◽  
Ruhua Zhang ◽  
...  
Keyword(s):  
Arctic Oscillation ◽  
Polar Vortex ◽  
The Arctic ◽  
Reanalysis Dataset ◽  
Stratospheric Polar Vortex ◽  
Eurasian Continent ◽  
Time Period ◽  
Action Center ◽  
The Arctic Oscillation ◽  
The Impact

AbstractUsing the ERA-Interim reanalysis dataset for the time period 1979–2016, we analyzed the influence of the stratospheric polar vortex shift on the Arctic Oscillation (AO) in winter (December–March). The results show that a shift in the stratospheric polar vortex toward the Eurasian continent is favorable for the occurrence of the negative phase of the AO. The duration of the AO events accompanied by the stratospheric polar vortex shift toward the Eurasian continent (AO-shift events) is longer than that of the remaining negative AO events (AO-noshift events), and the intensity of AO-shift events is greater than that of AO-noshift events from day 4 to day 15 of the life cycle of the events. The enhancement in the AO intensity during AO-shift events is likely due to downward extension of the stratospheric northern annular mode (NAM) signals and more poleward-propagating planetary waves in the troposphere and lower stratosphere and their convergence in the mid-high latitudes. Furthermore, the polar vortex shift can lead to changes in the intensity of the three action centers in the AO spatial pattern at 500 hPa. In general, during AO-shift events, the three action centers are stronger than those during AO-noshift events. There is an overall westward shift of the Arctic action center during AO-shift events, which may be closely related to the changes of Greenland blocking frequency.

scholarly journals A Numerical Sensitivity Study of the Influence of Siberian Snow on the Northern Annular Mode

2012 ◽  
Vol 25 (2) ◽  
pp. 592-607 ◽  
Author(s):  
Y. Peings ◽  
D. Saint-Martin ◽  
H. Douville
Keyword(s):  
General Circulation ◽  
Arctic Oscillation ◽  
Polar Vortex ◽  
Circulation Model ◽  
Sensitivity Study ◽  
The Arctic ◽  
Annular Mode ◽  
Northern Annular Mode ◽  
Model Free ◽  
The Arctic Oscillation

Abstract The climate version of the general circulation model Action de Recherche Petite Echelle Grande Echelle (ARPEGE-Climat) is used to explore the relationship between the autumn Siberian snow and the subsequent winter northern annular mode by imposing snow anomalies over Siberia. As the model presents some biases in the representation of the polar vortex, a nudging methodology is used to obtain a more realistic but still interactive extratropical stratosphere in the model. Free and nudged sensitivity experiments are compared to discuss the dependence of the results on the northern stratosphere climatology. For each experiment, a positive snow mass anomaly imposed from October to March over Siberia leads to significant impacts on the winter atmospheric circulation in the extratropics. In line with previous studies, the model response resembles the negative phase of the Arctic Oscillation. The well-documented stratospheric pathway between snow and the Arctic Oscillation operates in the nudged experiment, while a more zonal propagation of the signal is found in the free experiment. Thus, the study provides two main findings: it supports the influence of Siberian snow on the winter extratropical circulation and highlights the importance of the northern stratosphere representation in the models to capture this teleconnection. These findings could have important implications for seasonal forecasting, as most of the operational models present biases similar to those of the ARPEGE-Climat model.

scholarly journals The Effect of the Arctic Oscillation on the Predictability of Mid-High Latitude Circulation in December

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhihai Zheng ◽  
Jin Ban ◽  
Yongsheng Li
Keyword(s):  
Sea Ice ◽  
High Latitude ◽  
Arctic Oscillation ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
High Latitudes ◽  
Arctic Sea ◽  
High Predictability ◽  
The Arctic Oscillation ◽  
The Impact

The impact of the Arctic Oscillation (AO) on the predictability of mid-high latitude circulation in December is analysed using a full set of hindcasts generated form the Beijing Climate Center Atmospheric General Circulation Model version 2.2 (BCC_AGCM2.2). The results showed that there is a relationship between the predictability of the model on the Eurasian mid-high latitude circulation and the phase of AO, with the highest predictability in the negative AO phase and the lowest predictability in the normal AO phase. Moreover, the difference of predictability exists at different lead times. The potential sources of the high predictability in the negative AO phase in the BCC_AGCM2.2 model were further diagnosed. It was found that the differences of predictability on the Eurasian mid-high latitude circulation also exist in different Arctic sea ice anomalies, and the model performs well in reproducing the response of Arctic sea ice on the AO. The predictability is higher when sudden stratospheric warming (SSW) events occur, and strong SSW events tend to form a negative AO phase distribution in the Eurasian mid-high latitudes both in the observation and model. In addition, the model captured the blocking over the mid-high latitudes well, it may be related to the relatively long duration of the blocking. Changes in the AO will affect the blocking circulations over the mid-high latitudes, which partly explains the high predictability of the model in negative AO phases from the aspect of the internal atmospheric dynamics.

scholarly journals Volcanic Activity Sparks Arctic Oscillation

2021 ◽  
Author(s):  
Weizheng Qu ◽  
Fei Huang ◽  
Jinping Zhao ◽  
Ling Du ◽  
Yong Cao
Keyword(s):  
Volcanic Activity ◽  
Volcanic Eruption ◽  
Arctic Oscillation ◽  
Polar Vortex ◽  
Volcanic Eruptions ◽  
The Arctic ◽  
Vortex System ◽  
Significant Fluctuation ◽  
The Arctic Oscillation

Abstract The parasol effect of volcanic dust and aerosol caused by volcanic eruption results in the deepening and strengthening of the Arctic vortex system, thus stimulating or strengthening the Arctic Oscillation (AO). Three of the strongest AOs in more than a century have been linked to volcanic eruptions. Every significant fluctuation of the AO index (AOI) for many years has been associated with a volcanic eruption. Volcanic activity occurring at different locations in the Arctic vortex circulation will exert different effects on the polar vortex. Strong volcanic activity above level 5 erupting outside the Arctic vortex circulation can have a certain degree of influence on the Arctic oscillation and only cause small AOI fluctuations.

scholarly journals Beryllium-7 and Lead-210 are Associated with an Increase in the Arctic Oscillation: Evidence from Atmospheric Aerosols in a Remote Tropical Region in East Asia

2021 ◽  
Author(s):  
Xiaoxia Chen ◽  
Wuhui Lin ◽  
Xianwen He ◽  
Liangliang Feng ◽  
Kuo-Ying Wang
Keyword(s):  
East Asia ◽  
High Latitude ◽  
Arctic Oscillation ◽  
Meteorological Data ◽  
Large Fraction ◽  
The Arctic ◽  
Tropical Region ◽  
Monitoring Site ◽  
High Latitudes ◽  
The Arctic Oscillation

AbstractThe Arctic Oscillation (AO) accounts for a large fraction of recent decadal climate trends in Northern Hemisphere (NH) high latitudes. In East Asia, an elevated AO index (AOI) was associated with warmer temperatures in middle- to high-latitude regions, colder temperatures over low-latitude regions, and elevated ozone intrusion from the stratosphere. Elevated beryllium-7 (7Be) is produced in the stratosphere. Few studies have discussed the relationship between 7Be and the AO. Here, we identify the AO signature in 7Be and lead (Pb)-210 observed at a tropical ambient monitoring site in Nanning (22.8°N, 108.5°E) during the December 2014–December 2017 period. Our results show that the 7Be and 210Pb concentrations are positively and significantly correlated with the AOI (P < 0.01). These results show that elevated 7Be and 210Pb are associated with an increase in the AOI, reflecting air masses originating from NH high latitudes and vertically from the high-latitude upper troposphere and lower stratosphere regions to tropical latitudes in East Asia. These results have been verified with ozonesonde data without seasonality and with two meteorological data sets. Our results are also confirmed by observational data over the Pacific regions. We conclude that the AO exerts impacts over the tropical regions in East Asia, and 7Be can be used as a tracer to track the impacts of the AO.

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.

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