Decadal changes in the link between El Niño and springtime North Atlantic oscillation and European-North African rainfall

2003 ◽  
Vol 23 (11) ◽  
pp. 1293-1311 ◽  
Author(s):  
Peter Knippertz ◽  
Uwe Ulbrich ◽  
Filipa Marques ◽  
João Corte-Real
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
North African ◽  
African Rainfall ◽  
European North

scholarly journals Simulated coordinated impacts of the previous autumn North Atlantic Oscillation (NAO) and winter El Niño on winter aerosol concentrations over eastern China

2019 ◽  
Vol 19 (16) ◽  
pp. 10787-10800 ◽  
Author(s):  
Juan Feng ◽  
Jianping Li ◽  
Hong Liao ◽  
Jianlei Zhu
Keyword(s):  
North Atlantic Oscillation ◽  
South China ◽  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
Eastern China ◽  
Central China ◽  
Boreal Winter ◽  
The Impact ◽  
Previous Autumn

Abstract. The high aerosol concentration (AC) over eastern China has attracted attention from both science and society. Based on the simulations of a chemical transport model using a fixed emissions level, the possible impact of the previous autumn North Atlantic Oscillation (NAO) combined with the simultaneous El Niño–Southern Oscillation (ENSO) on the boreal winter AC over eastern China is investigated. We find that the NAO only manifests its negative impacts on the AC during its negative phase over central China, and a significant positive influence on the distribution of AC is observed over south China only during the warm events of ENSO. The impact of the previous NAO on the AC occurs via an anomalous sea surface temperature tripole pattern by which a teleconnection wave train is induced that results in anomalous convergence over central China. In contrast, the occurrence of ENSO events may induce an anomalous shift in the western Pacific subtropical high and result in anomalous southwesterlies over south China. The anomalous circulations associated with a negative NAO and El Niño are not favorable for the transport of AC and correspond to worsening air conditions over central and south China. The results highlight the fact that the combined effects of tropical and extratropical systems play a considerable role in affecting the boreal winter AC over eastern China.

scholarly journals Association between stroke occurrence and changes in atmospheric circulation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jone Vencloviene ◽  
Ricardas Radisauskas ◽  
Daina Kranciukaite-Butylkiniene ◽  
Abdonas Tamosiunas ◽  
Vidmantas Vaiciulis ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
El Niño ◽  
Arctic Oscillation ◽  
El Nino ◽  
Teleconnection Pattern ◽  
East Atlantic ◽  
Negatively Associated ◽  
The Impact

Abstract Background The impact of weather on morbidity from stroke has been analysed in previous studies. As the risk of stroke was mostly associated with changing weather, the changes in the daily stroke occurrence may be associated with changes in atmospheric circulation. The aim of our study was to detect and evaluate the association between daily numbers of ischaemic strokes (ISs) and haemorrhagic strokes (HSs) and the teleconnection pattern. Methods The study was performed in Kaunas, Lithuania, from 2000 to 2010. The daily numbers of ISs, subarachnoid haemorrhages (SAHs), and intracerebral haemorrhages (ICHs) were obtained from the Kaunas Stroke Register. We evaluated the association between these types of stroke and the teleconnection pattern by applying Poisson regression and adjusting for the linear trend, month, and other weather variables. Results During the study period, we analysed 4038 cases (2226 men and 1812 women) of stroke. Of these, 3245 (80.4%) cases were ISs, 533 (13.2%) cases were ICHs, and 260 (6.4%) cases were SAHs. An increased risk of SAH was associated with a change in mean daily atmospheric pressure over 3.9 hPa (RR = 1.49, 95% CI 1.14–1.96), and a stronger El Niño event had a protective effect against SAHs (RR = 0.34, 95% CI 0.16–0.69). The risk of HS was positively associated with East Atlantic/West Russia indices (RR = 1.13, 95% CI 1.04–1.23). The risk of IS was negatively associated with the Arctic Oscillation index on the same day and on the previous day (RR = 0.97, p < 0.033). During November–March, the risk of HS was associated with a positive North Atlantic Oscillation (NAO) (RR = 1.29, 95% CI 1.03–1.62), and the risk of IS was negatively associated with the NAO index (RR = 0.92, 95% CI 0.85–0.99). Conclusions The results of our study provide new evidence that the North Atlantic Oscillation, Arctic Oscillation, East Atlantic/West Russia, and El Niño-Southern Oscillation pattern may affect the risk of stroke. The impact of these teleconnections is not identical for various types of stroke. Emergency services should be aware that specific weather conditions are more likely to prompt calls for more severe strokes.

scholarly journals Association Between Stroke Occurrence And Changes In Atmospheric Circulation 

2020 ◽  
Author(s):  
Jone Vencloviene ◽  
Ricardas Radisauskas ◽  
Daina Kranciukaite-Butylkiniene ◽  
Abdonas Tamosiunas ◽  
Vidmantas Vaiciulis ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
El Niño ◽  
Arctic Oscillation ◽  
El Nino ◽  
Teleconnection Pattern ◽  
East Atlantic ◽  
Negatively Associated ◽  
The Impact

Abstract Background: The impact of weather on morbidity from stroke has been analysed in previous studies. As the risk of stroke was mostly associated with changing weather, the changes in the daily stroke occurrence may be associated with changes in atmospheric circulation. The aim of our study was to detect and evaluate the association between daily numbers of ischaemic strokes (ISs) and haemorrhagic strokes (HSs) and the teleconnection pattern.. Methods: The study was performed in Kaunas, Lithuania, from 2000 to 2010. The daily numbers of ISs, subarachnoid haemorrhages (SAHs), and intracerebral haemorrhages (ICHs) were obtained from the Kaunas Stroke Register. We evaluated the association between these types of stroke and the teleconnection pattern by applying Poisson regression and adjusting for the linear trend, month, and other weather variables. Results: During the study period, we analysed 4,038 cases (2,226 men and 1,812 women) of stroke. Of these, 3,245 (80.4%) cases were ISs, 533 (13.2%) cases were ICHs, and 260 (6.4%) cases were SAHs. An increased risk of SAH was associated with a change in mean daily atmospheric pressure over 3.9 hPa (RR=1.49, 95% CI 1.14-1.96), and a stronger El Niño event had a protective effect against SAHs (RR=0.34, 95% CI 0.16-0.69). The risk of HS was positively associated with East Atlantic/West Russia indices (RR=1.13, 95% CI 1.04-1.23). The risk of IS was negatively associated with the Arctic Oscillation index on the same day and on the previous day (RR=0.97, p<0.033). During November-March, the risk of HS was associated with a positive North Atlantic Oscillation (NAO) (RR=1.29, 95% CI 1.03-1.62), and the risk of IS was negatively associated with the NAO index (RR=0.92, 95% CI 0.85-0.99). Conclusions: The results of our study provide new evidence that the North Atlantic Oscillation, Arctic Oscillation, East Atlantic/West Russia, and El Niño-Southern Oscillation pattern may affect the risk of stroke. The impact of these teleconnections is not identical for various types of stroke. Emergency services should be aware that specific weather conditions are more likely to prompt calls for more severe strokes.

scholarly journals Pattern Recognition Methods to Separate Forced Responses from Internal Variability in Climate Model Ensembles and Observations

2020 ◽  
Vol 33 (20) ◽  
pp. 8693-8719 ◽  
Author(s):  
Robert C. J. Wills ◽  
David S. Battisti ◽  
Kyle C. Armour ◽  
Tapio Schneider ◽  
Clara Deser
Keyword(s):  
Climate Change ◽  
Pattern Recognition ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
El Niño ◽  
Climate Model ◽  
El Nino ◽  
Internal Variability ◽  
Forced Response ◽  
Large Ensembles

AbstractEnsembles of climate model simulations are commonly used to separate externally forced climate change from internal variability. However, much of the information gained from running large ensembles is lost in traditional methods of data reduction such as linear trend analysis or large-scale spatial averaging. This paper demonstrates how a pattern recognition method (signal-to-noise-maximizing pattern filtering) extracts patterns of externally forced climate change from large ensembles and identifies the forced climate response with up to 10 times fewer ensemble members than simple ensemble averaging. It is particularly effective at filtering out spatially coherent modes of internal variability (e.g., El Niño, North Atlantic Oscillation), which would otherwise alias into estimates of regional responses to forcing. This method is used to identify forced climate responses within the 40-member Community Earth System Model (CESM) large ensemble, including an El Niño–like response to volcanic eruptions and forced trends in the North Atlantic Oscillation. The ensemble-based estimate of the forced response is used to test statistical methods for isolating the forced response from a single realization (i.e., individual ensemble members). Low-frequency pattern filtering is found to skillfully identify the forced response within individual ensemble members and is applied to the HadCRUT4 reconstruction of observed temperatures, whereby it identifies slow components of observed temperature changes that are consistent with the expected effects of anthropogenic greenhouse gas and aerosol forcing.

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