Exploring the phase-strength asymmetry of the North Atlantic Oscillation using conditional nonlinear optimal perturbation

2015 ◽  
Vol 32 (5) ◽  
pp. 671-679 ◽  
Author(s):  
Zhina Jiang ◽  
Xin Wang ◽  
Donghai Wang
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Conditional Nonlinear Optimal Perturbation ◽  
Optimal Perturbation ◽  
The North ◽  
Strength Asymmetry ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

scholarly journals A Study of the North Atlantic Oscillation Using Conditional Nonlinear Optimal Perturbation

2013 ◽  
Vol 70 (3) ◽  
pp. 855-875 ◽  
Author(s):  
Zhina Jiang ◽  
Mu Mu ◽  
Dehai Luo
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Nonlinear Process ◽  
Dipole Mode ◽  
Conditional Nonlinear Optimal Perturbation ◽  
Global Spectral Model ◽  
Optimal Perturbation ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract The conditional nonlinear optimal perturbation (CNOP) method is used to explore the optimal precursors that trigger the North Atlantic Oscillation (NAO) anomaly pattern with a triangular T21, three-level, quasi-geostrophic global spectral model based on a viewpoint that the NAO is a nonlinear initial-value problem. With a three-dimensional winter climatological flow as the basic state, initially baroclinic localized optimal precursors on the northward flanks of the climatological Atlantic jet undergo wave breaking during their evolution into the NAO-like anomalies. Accompanied with the formation of the NAO, the north–south variability of the zonal mean westerly anomaly has arisen. Analysis reveals that in the evolution of optimal precursors, the role played by the self-interaction of perturbations (viz., the nonlinear process) in the onset of the negative-phase NAO (NAO−) event is stronger than that in the onset of the positive-phase NAO (NAO+) event. Both the perturbation/basic-state interaction and self-interaction of perturbations determine whether the NAO− event occurs, whereas the nonlinearity process in the NAO+ onset only appears to modulate the structure of the perturbation to have a dipole mode over the North Atlantic at the optimization time, and meanwhile cause this dipole mode to become zonally extended. That is to say, the nonlinear process indeed plays an important role during the onset of an NAO event and the CNOP method is a useful tool to identify the dynamics of the onset of NAO teleconnection patterns.

scholarly journals Influence of the North Atlantic oscillation on the atmospheric levels of benzo[a]pyrene over Europe

2021 ◽  
Author(s):  
Pedro Jiménez-Guerrero ◽  
Nuno Ratola
Keyword(s):  
Spatial Pattern ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Transport Model ◽  
Regional Scale ◽  
The South ◽  
Climatic Fluctuations ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractThe atmospheric concentration of persistent organic pollutants (and of polycyclic aromatic hydrocarbons, PAHs, in particular) is closely related to climate change and climatic fluctuations, which are likely to influence contaminant’s transport pathways and transfer processes. Predicting how climate variability alters PAHs concentrations in the atmosphere still poses an exceptional challenge. In this sense, the main objective of this contribution is to assess the relationship between the North Atlantic Oscillation (NAO) index and the mean concentration of benzo[a]pyrene (BaP, the most studied PAH congener) in a domain covering Europe, with an emphasis on the effect of regional-scale processes. A numerical simulation for a present climate period of 30 years was performed using a regional chemistry transport model with a 25 km spatial resolution (horizontal), higher than those commonly applied. The results show an important seasonal behaviour, with a remarkable spatial pattern of difference between the north and the south of the domain. In winter, higher BaP ground levels are found during the NAO+ phase for the Mediterranean basin, while the spatial pattern of this feature (higher BaP levels during NAO+ phases) moves northwards in summer. These results show deviations up to and sometimes over 100% in the BaP mean concentrations, but statistically significant signals (p<0.1) of lower changes (20–40% variations in the signal) are found for the north of the domain in winter and for the south in summer.

Polar motion and the North Atlantic Oscillation

1997 ◽  
Vol 42 (11) ◽  
pp. 927-931 ◽  
Author(s):  
Yonghong Zhou ◽  
Dawei Zheng ◽  
Benjamin Fong Chao
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Polar Motion ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

scholarly journals Global drivers effect in multi-annual variability of runoff

2014 ◽  
Vol 62 (3) ◽  
pp. 169-176 ◽  
Author(s):  
Miriam Fendeková ◽  
Pavla Pekárová ◽  
Marián Fendek ◽  
Ján Pekár ◽  
Peter Škoda
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Coherence Function ◽  
Climatic Conditions ◽  
Base Flow ◽  
Quasi Biennial Oscillation ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
Biennial Oscillation

Abstract Changes in runoff parameters are very important for Slovakia, where stream-flow discharges, being supplied by precipitation and groundwater runoff, are preferentially influenced by climatic conditions. Therefore, teleconnections between runoff parameters, climate parameters and global atmospheric drivers such as North Atlantic Oscillation, Southern Pacific Oscillation, Quasi-biennial oscillation and solar activity were studied in the Nitra River Basin, Slovakia. Research was mostly based on records of 80 years (1931-2010) for discharges and baseflow, and 34 years for groundwater heads. Methods of autocorrelation, spectral analysis, cross-correlation and coherence function were used. Results of auto- correllograms for discharges, groundwater heads and base flow values showed a very distinct 11-year and 21-year periodicity. Spectrogram analysis documented the 11-year, 7.8-year, 3.6-year and 2.4-year periods in the discharge, precipitation and air temperature time series. The same cycles except of 11-years were also identified in the long-term series of the North Atlantic Oscillation and Southern Pacific Oscillation indices. The cycle from approximately 2.3 to 2.4-years is most likely connected with Quasi-biennial oscillation. The close negative correlation between the North Atlantic Oscillation winter index and the hydrological surface and groundwater parameters can be used for their prediction within the same year and also for one year in advance.

scholarly journals Seasonal Predictability of the North Atlantic Oscillation and Zonal Mean Fields Associated with Stratospheric Influence in JMA/MRI-CPS2

SOLA ◽  
2017 ◽  
Vol 13 (0) ◽  
pp. 209-213 ◽  
Author(s):  
Naoaki Saito ◽  
Shuhei Maeda ◽  
Tosiyuki Nakaegawa ◽  
Yuhei Takaya ◽  
Yukiko Imada ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Seasonal Predictability ◽  
The North ◽  
Mean Fields ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

scholarly journals The influence of the North Atlantic Oscillation on diverse renewable generation in Scotland

2017 ◽  
Vol 205 ◽  
pp. 855-867 ◽  
Author(s):  
Andrew N. Commin ◽  
Andrew S. French ◽  
Matteo Marasco ◽  
Jennifer Loxton ◽  
Stuart W. Gibb ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Renewable Generation ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation
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