scholarly journals The Association Between the North Atlantic Oscillation and the Interannual Variability of the Tropospheric Transport Pathways in Western Europe

2013 ◽  
pp. 127-142 ◽  
Author(s):  
J. A. G. Orza ◽  
M. Cabello ◽  
V. Galiano ◽  
A. T. Vermeulen ◽  
A. F. Stein
Keyword(s):  
North Atlantic Oscillation ◽  
Interannual Variability ◽  
North Atlantic ◽  
Western Europe ◽  
Transport Pathways ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Decadal Relationship between European Blocking and the North Atlantic Oscillation during 1978–2011. Part I: Atlantic Conditions

2015 ◽  
Vol 72 (3) ◽  
pp. 1152-1173 ◽  
Author(s):  
Dehai Luo ◽  
Yao Yao ◽  
Aiguo Dai
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Western Europe ◽  
Storm Track ◽  
Western Atlantic ◽  
Atlantic Sector ◽  
The North ◽  
Nao Index ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract Both the positive and negative phases of the North Atlantic Oscillation (NAO+ and NAO−, respectively) and atmospheric blocking in the Euro-Atlantic sector reflect synoptic variability over the region and thus are intrinsically linked. This study examines their relationship from a decadal change perspective. Since the winter-mean NAO index is defined as a time average of instantaneous NAO indices over the whole winter, it is unclear how the activity of European blocking (EB) events can be related to the variation of the positive mean NAO index. Here, this question is examined by dividing the winter period 1978–2011 into two decadal epochs: 1978–94 (P1) with an increasing and high NAO index and 1995–2011 (P2) with a decreasing and low NAO index. Using atmospheric reanalysis data, it is shown that there are more intense and persistent EB events in eastern Europe during P1 than during P2, while the opposite is true for western Europe. It is further shown that there are more NAO+ (NAO−) events during P1 (P2). The EB events associated with NAO+ events extend more eastward and are associated with stronger Atlantic mean zonal wind and weaker western Atlantic storm track during P1 than during P2, but EB events associated with NAO− events increase in western Europe under opposite Atlantic conditions during P2. Thus, the increase in the number of individual NAO+ (NAO−) events results in more EB events in eastern (western) Europe during P1 (P2). The EB change is also associated with the increased frequency of NAO− to NAO+ (NAO+ to NAO−) transition events.

scholarly journals Intercontinental transport of tropospheric ozone: a study of its seasonal variability across the North Atlantic utilizing tropospheric ozone residuals and its relationship to the North Atlantic Oscillation

2003 ◽  
Vol 3 (6) ◽  
pp. 2053-2066 ◽  
Author(s):  
J. K. Creilson ◽  
J. Fishman ◽  
A. E. Wozniak
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Tropospheric Ozone ◽  
Total Ozone ◽  
Western Europe ◽  
Positive Phase ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
The Impact

Abstract. Using the empirically-corrected tropospheric ozone residual (TOR) technique, which utilizes coincident observations of total ozone from the Total Ozone Mapping Spectrometer (TOMS) and stratospheric ozone profiles from the Solar Backscattered Ultraviolet (SBUV) instruments, the seasonal and regional distribution of tropospheric ozone across the North Atlantic from 1979-2000 is examined. Its relationship to the North Atlantic Oscillation (NAO) is also analyzed as a possible transport mechanism across the North Atlantic. Monthly climatologies of tropospheric ozone for five different regions across the North Atlantic exhibit strong seasonality. The correlation between these monthly climatologies of the TOR and ozonesonde profiles at nearby sites in both eastern North America and western Europe are highly significant (R values of +0.98 and +0.96 respectively) and help to validate the use of satellite retrievals of tropospheric ozone. Distinct springtime interannual variability over North Atlantic Region 5 (eastern North Atlantic-western Europe) is particularly evident and exhibits similar variability to the positive phase of the NAO (R=+0.61, r=<0.01). Positive phases of the NAO are indicative of a stronger Bermuda-Azores high and a stronger Icelandic low and thus faster more zonal flow across the North Atlantic from west to east. This flow regime appears to be causing the transport of tropospheric ozone across the North Atlantic and onto Europe. The consequence of such transport is the impact on a downwind region's ability to meet their ozone attainment goals. This link between the positive phase of the NAO and increased tropospheric ozone over Region 5 could be an important tool for prediction of such pollution outbreaks.

scholarly journals Intercontinental transport of tropospheric ozone: A study of its seasonal variability across the North Atlantic utilizing tropospheric ozone residuals and its relationship to the North Atlantic Oscillation

2003 ◽  
Vol 3 (4) ◽  
pp. 4431-4460 ◽  
Author(s):  
J. K. Creilson ◽  
J. Fishman ◽  
A. E. Wozniak
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Tropospheric Ozone ◽  
Total Ozone ◽  
Western Europe ◽  
Positive Phase ◽  
The North ◽  
The North Atlantic ◽  
Eastern North Atlantic ◽  
The North Atlantic Oscillation

Abstract. Using the empirically-corrected tropospheric ozone residual (TOR) technique, which utilizes coincident observations of total ozone from the Total Ozone Mapping Spectrometer (TOMS) and stratospheric ozone profiles from the Solar Backscattered Ultraviolet (SBUV) instruments, the seasonal and regional distribution of tropospheric ozone across the North Atlantic from 1979–2000 is examined. Its relationship to the North Atlantic Oscillation (NAO) is also analyzed as a possible transport mechanism across the North Atlantic. Monthly climatologies of tropospheric ozone for five different regions across the North Atlantic exhibit strong seasonality. The correlation between these monthly climatologies of the TOR and adjacent ozonesonde profiles in both Region 1 (eastern North America-western North Atlantic) and Region 5 (eastern North Atlantic-western Europe) are highly significant (R values of +0.98 and +0.96, respectively) and help to validate the use of satellite retrievals of tropospheric ozone. Distinct springtime interannual variability over North Atlantic Region 5 (eastern North Atlantic-western Europe) is particularly evident and exhibits similar variability to the positive phase of the NAO (R=+0.61, ρ =<0.01). Positive phases of the NAO are indicative of a stronger Bermuda-Azores high and a stronger Icelandic low and thus faster more zonal flow across the North Atlantic from west to east. This flow regime appears to be causing the transport of tropospheric ozone across the North Atlantic and onto Europe. The consequence of such transport is the impact on a downwind region's ability to meet their ozone attainment goals. This link between the positive phase of the NAO and increased tropospheric ozone over Region 5 could be an important tool for prediction of such pollution outbreaks.

Weather Regime Transitions and the Interannual Variability of the North Atlantic Oscillation. Part I: A Likely Connection

2012 ◽  
Vol 69 (8) ◽  
pp. 2329-2346 ◽  
Author(s):  
Dehai Luo ◽  
Jing Cha ◽  
Steven B. Feldstein
Keyword(s):  
Cluster Analysis ◽  
North Atlantic Oscillation ◽  
Interannual Variability ◽  
North Atlantic ◽  
Weather Regime ◽  
The North ◽  
Nao Index ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
Regime Transitions

Abstract In this study, the relationship between weather regime transitions and the interannual variability of the North Atlantic Oscillation (NAO) in winter during 1978–2008 is examined by using a statistical approach. Four classical weather regimes—the two phases of the NAO (NAO+, NAO−) and the Scandinavian blocking and Atlantic ridge patterns—are obtained with k-means cluster analysis. Observations show that the transition between the NAO+ and NAO− regimes is markedly different between 1978–90 (P1) and 1991–2008 (P2). Within P1 (P2), the frequency of the NAO− to NAO+ (NAO+ to NAO−) transition events is almost twice that of the NAO+ to NAO− (NAO− to NAO+) transition events. On this basis, further cluster analysis performed for two cases with and without NAO transition events indicates that within P1 (P2) the NAO+ (NAO−) anomaly is markedly enhanced as the NAO− to NAO+ (NAO+ to NAO−) transitions take place. Furthermore, the NAO regime transition is found to be more likely to enhance the eastward shift of the NAO+ (NAO−) anomaly. Thus, it is hypothesized that the interannual change in the winter-mean NAO index from P1 to P2 is related to the intraseasonal NAO− to NAO+ (NAO+ to NAO−) transition events during P1 (P2) because of the variation of the NAO pattern in intensity, location, and frequency (number of days). This finding is also seen from calculations of the winter monthly mean NAO index with and without NAO regime transitions.

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.

Sign in / Sign up

Export Citation Format

Share Document